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Honeywell CHRONOTHERM T8621A User's Manual

1. T8621A C D INSTALLATION HOT L2 SYSTEM TRANSFORMER A 8 4 AN lt lt OPERATION OMIT SWITCH WI ELECTRIC L HEAT 1 NON ELECTRIC E Hw SYSTEM HEAT 2 HEATING SWITCH CHANGEOVER RELAY HEAT THERMOSTAT lt lt t 8 T LOGIC CIRCUIT OFF lt COOLING CHANGEOVER RELAY H COOL 1 COOL 2 COMPRESSOR K CONTACTOR lt SUBBASE Z CONTROL CIRCUIT FAN SWITCH o FAN RELAY AUTO ON RO NI A POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED A FAN OPERATION SWITCH MAY BE IN EITHER POSITION Refer to Figs 8 14 for typical hookups of subbase and thermostat ADJUSTING CYCLE RATE To customize the thermostat cycling performance to various types of heating equipment cycle rate adjustment screws are provided on the back of the thermostat to provide optimum room temperature control NOTE Most applications will not require a change in A A DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION NOMINAL 24 VAC POWER MUST BE PRESENT BETWEEN R AND C FOR THERMOSTAT OPERATION NOTE THERMOSTAT DOES NOT PROVIDE MINIMUM OFF TIME IN 15 HEATING M1546A cycle rate The room air temperature will normally vary slightly from the comfort temperature setting with the cycling of the fur nace or air conditioner The cooling cycle rate is factory set
2. radiant heat from sun or appliances concealed pipes and chimneys unheated uncooled areas behind the thermostat such as an outside wall IMPORTANT The T8621 requires on additional conduc tor io transformer common to provide continuous 24V power for thermostat operation WHEN INSTALLING THIS PRODUCT Read these instructions carefully Failure to fol low them could damage the product or cause a hazardous condition 2 Check the ratings given on the product to make sure the product is suitable for your application 3 Installer must be a trained experienced service technician 4 Allow thermostat to warm to room temperature be fore operating 5 After installation is complete check out product operation as provided in these instructions Thermostat with Remote Mounted Sensor Install thermostat in an area that is accessible for setting and adjusting the temperature and settings 7 68 0058 1 18621A C D INSTALLATION Install remote temperature sensor in an area with good air circulation at average temperature Do not install the sensor where it may be affected by drafts or dead spots behind doors in corners or under cabinets hot or cold air from ducts radiant heat from sun or appliances concealed pipes and chimneys unheated uncooled areas behind the sensor such as an outside wall IF REPLACING AN EXISTING THERMOSTAT Turn off thermostat power at furnace or boiler
3. SETTING ture setting Press and release to cancel manual PROGRAM control CANCELING PROGRAM p Press and hold until the desired time GHS SETTINGS PERIOD period shows on the display WON a m The thermostat requires time and tem perature settings in MORNING time p q Press and hold until the desired day inna Bus period for each day but any of the DAY shows on the display EEG 7 others can be canceled Each time pe riod for each day must be canceled separately Press and release to cancel the time and PERIOD temperature settings for that time pe wen HEAT riod Both the heating and cooling tem peratures will be canceled Use the copy function to cancel the RUN Press and release to return to normal program from other days but remem operation a ber that all the programs will be copied not just the cancellation 26 CHECKING THE PROGRAM TIMES AND TEMPERATURES If desired check all the stored set tings without affecting the perma nent program CHECKING THE CURRENT TEMPERATURE SETTING Press a single key to compare actual room temperature to the setting at any time Iz lt RUN PROGRAM PRESENT SETTING T8621A C D OPERATING THE THERMOSTAT Press and hold until the desired period shows on the display The start time and temperature setting will appear on the display Press and release to display the next day time and temperature f
4. BAT Homeowner will have 20 30 seconds to install new batteries after removing old batteries from back of thermo stat After 20 30 seconds it will be necessary to reprogram REPL BAT indication will disappear when thermostat is mounted back on the subbase IMPORTANT For proper thermostat operation always replace dead batteries with new alkaline batteries If batteries are completely dead the display will go blank when the thermostat is removed from the subbase After replacing the batteries reprogramming will be necessary 16 Fig 16 Battery placement PLACEMENT NOTE CORRECT PLUS AND MINUS DIRECTION 12 289 POWER OUTAGES Backup batteries will hold the programming and keep the display on during most power outages Once the power is restored the system will resume normal operation If the display goes off when power is lost either the backup batteries need to be replaced or are not installed When power is restored the display will flash 1 00 PM asa reminder to reprogram MOUNTING THE THERMOSTAT With system switch set to OFF hang the thermostat on the tabs at the top of the subbase Fig 17A Swing down andpress on lower edge until thermostat snaps in place Fig 17B Open cover and tighten the captive mounting screws Fig 17C SETTING DAY AND TIME Restore 24V power to the thermostat When power is applied to the thermostat the display will read 1 00 PM and room temperature It will go off fora fe
5. 26 Checking the Program Times and Temperatures sseseeseseeeeeneeneeneenenee nennen trennen 27 Checking the Current Temperature Setting nn eene nennen 27 Op ration teni epe p Ee C ah PORTE ee rho eH e gie ee PRO e re e NEK 28 ADAPTIVE INTELLIGENT RECOVERY M Operation enne nene een rennen enne nn teens 28 What to Expect During Recovery from Energy Savings in Heating 2 28 Thermal Performance with T8062 beers teet nicer ie t tmt tere e t dee a eee 28 Mi imum Off Timing e eon oie epe ipe eget e te UE P RR PE E aus 28 Troubleshooting er e REL ac EUG bete ee eh GG SN a aga tt iu te bc ie 29 GloSsaty een t bec hades s ERU etes ibt e ee Ee vetu te i ee Mad He ai e 30 This equipment is a Class B digital apparatus which complies with Canadian Radio Interference Regulations CRC c 1374 31 68 0058 1 Honeywell Home and Building Control Honeywell Inc 1985 Douglas Drive North Golden Valley MN 55422 Printed in U S A Home and Building Control Honeywell Limited Honey well Limit e 740 Ellesmere Road Scarborough Ontario 2V9
6. 5 1 0 3 F 24 HEAT C 12 COOL AUTO 2 or OFF 5 C 24 COOL AUTO or OFF 6 C 12 HEAT 7 C 24 HEAT e Programming the Thermostat STEP 1 SET Press and release The display shows ENTER THE DAY AND TIME DAY TIME 1 00 PM Mon This thermostat can be programmed lt Press and hold until the current day either wall or in hand See page 8 to DAY appears in the display T find out how to remove the thermostat from the subbase TIME Alwayspressthe keys with fingertip or similar blunt tool Sharp instruments like a pen or pencil point can damage the keyboard NOTE Check the glossary page 30 for definitions of unfamiliar Words appears in the display Be sure AM or Press and hold until the current time PM appears as desired BACK m d This completes setting the current day and time Go on to Step 2 19 68 0058 1 T8621A C D PROGRAMMING THE THERMOSTAT STEP 2 SET THE PROGRAM TIMES AND TEMPERATURES FOR ONE DAY Choose a day to program first Monday is used in the examples Start by pro gramming the MORNING time and temperatures The thermostat requires a MORNING program every day Set additional programs as desired Program the MIDDAY time and heat ing temperature if desired NOTE It is possible to cancel any pe riod showing on the display except MORNING by pushing the CAN CEL PERIOD key To move to the next period while programming simply press the PERIOD key again
7. A two transformer system may require turning off two switches or disconnects Remove any existing wallplate or subbase from wall Toavoid miswiring later label or write down each wire color with the letter or number on the wiring terminal as the wire is removed IF NEW INSTALLATION Run cable to a hole at the selected wall location for the thermostat and pull about 3 in 76 mm of wire through the opening Color coded 18 gauge thermostat cable with at least one conductor for each wiring terminal is recom mended Good service practice recommends selecting cable with one or two more conductors than the immediate appli cation requires If using thermostat model with remote temperature sens ing run 3 wire 18 gauge thermostat cable from the thermo stat location to the sensor location 200 ft 61 m maximum Route cable away from sources of electrical noise MOUNTING SUBBASE IMPORTANT Set the system switch to the OFF position before mounting NOTE The subbase does not require leveling for proper operation but for appearance only Fig 4 Removing thermostat from subbase Remove thermostat from subbase Fig 4 The subbase mounts directly onto the wall with the screws and anchors included If dry wall construction plastic anchors mustbe used use the subbaseas a template and with a pencil mark the two mounting screw positions Fig 5 Use 3 16 in bit to drill holes for anchors Gently tap anchors into holes u
8. In severe weather a conventional thermostat with a heat anticipator tends to turn off the thermostat too soon so the effective control point is somewhat below the setpoint In very cold weather the difference between setpoint and effective control point may be 5 or 6 F 2 or 3 C with a conventional thermostat This phenomenon is called droop Proportional plus integral action eliminates droop by adjusting the on time of the stage that is cycling longer or shorter until the control point matches the setpoint The T8621 maintains space temperature within one degree of setpoint when the temperature has stabilized after an energy savings period This zero droop performance of the T8621 provides improved occupant comfort and energy savings Occu pants do not need to continually adjust thermostat settings to maintain desired temperature even during severe weather MINIMUM OFF TIMING A minimum off timer in the T8621 ensures that the compressor will not come on again for at least five minutes after it turns off The minimum off timer is triggered when the compressor goes off and when the system switch is moved If the compress or turns off when the setpoint is changed or the CHANGE TO LAST PERIOD key is pressed then the minimum off timer is triggered The minimum off timer operates during only cooling T8621A C D TROUBLESHOOTING Troubleshooting SYMPTOM POSSIBLE CAUSE ACTION ROOM TEMPERATURE DISPLA
9. Press and release Note that the display shows MORNING and the preprogram med time and temperature If the display reads COOL press and release to switch to HEAT Press and hold until MONDAY or the desired day appears in the display Press and hold until the display shows the time that the temperature should be at the comfort setting Press and hold until the display shows the desired heating temperature If the display flashes while holding down TEMPERATURE WARMER or COOLER the setting limit has been reached If thermostat is an auto changeover model the heating tempera ture must be at least 3 degrees below the air conditioning temperature For ex ample if the cooling setting is 75 F the maximum heating setting is 72 F To set a higher heating temperature first raise the cooling setting Press and release The display shows MIDDAY but no time or temperature Press and hold until the display shows the time to start the energy saving pe riod Press and hold until the display shows the desired temperature 20 re Cree MON HEAT MORNING J 7t AM JALU LI OG MON HEAT MORNING J t Yt AM 719 Cree MON HEAT MORNING TTO AM r tL MON HEAT MORNING FOAM CLO MON HEAT MORNING o SET PT MON HEAT MIDDAY F 10 Ft Tt LL MON HEAT MIDDAY T8621A C D PROGRAMMIN
10. 1 LOGIC AUTO N PR BN FAN RELAY RA Li 89 HOT L2 COOLING A TRANSFORMER A POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED A FOR SINGLE TRANSFORMER SYSTEM JUMPER R AND RC A NOMINAL 24 Vac POWER MUST BE PRESENT BETWEEN R AND C FOR THERMOSTAT OPERATION 11 A APPLICABLE ONLY ON T8621D MODEL WITH REMOTE SENSOR A RECOMMENDED INTERCONNECT CABLE 18 GAUGE THERMOSTAT CABLE 200 ft 61 m MAXIMUM LENGTH ROUTE INTERCONNECT CABLE AWAY FROM SOURCES OF ELECTRICAL NOISE A DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION M1031E 68 0058 1 T8621A C D INSTALLATION Fig 11 T8621D 2 stage heat 2 stage cool thermostat with HEAT OFF COOL system and AUTO ON fan switching auto fan on heat and cool convertible to auto fan on cool only L1 HOT 12 A HEATING TRANSFORMER Y R A A lt lt POWER Z SUPPLY SN HIGH LIMIT OPERATION LIMIT STAGE 1 ELECTRIC elt HEAT RELAY HEAT 1 NON ELECTRIC A SYSTEM HEAT 2 STAGE 2 lt SWITCH HEAT RELAY HEAT THERMOSTAT lt amp LOGIC CIRCUIT OFF HEATING DAMPER OR COOL CHANGEOVER RELAY COOLING DAMPER OR CHANGEOVER RELAY moed STAGE 2 COOLING RELAY Hao Eel COOL coole STAGE 1 LING RELAY lt SUBBASE COOLING CONTROL Q CIRCUIT FAN lt SWITCH_ FAN RELAY AUTO e A
11. Blank TO CHECK 12 See note A E ACH PERIOD POSITION OFF 08 Blank PERIOD thm 13 Microprocessor mask zd no and revision no 09 Blank 14 Blank DAY TIME HEAT or 14 Iststage heating and AUTO DAY TIME SYSTEM LED on 14 2nd stage heating DAY TIME also on 14 2nd stage heating off DAY TIME 14 Ist stage heating and DAYTIME SYSTEM LED off NOTE If single stage heating system press key twice instead of 4 times once to turn heating and SYSTEM LED on second time to turn off OFF 10 Blank TEMP RUN 11 Normal operating display END SELF TEST N Forelectric heatfan operation The fan will operate with the heating system when fan switch is in AUTO HEAT displayed when system switch is in HEAT COOL when in COOL HEAT and COOL when in AUTO neither when in OFF Also a four digit code is displayed with each digit explained below T8621A C D CHECKOUT e PROGRAMMING THE THERMOSTAT Cycle Rate Setting Third Manual or Auto System Switch cph at 50 on time for stage Digit Changeover Position First 1 on 1 heat models stage 0 Manual HEAT or OFF a 2on net models 1 Aute HEAT or OFF i 3 3 Auto AUTO 5 4 Manual COOL 2 3 Auto COOL 3 6 Second Stages of Fourth Clock System Switch Digit Heat Cool Digit Degrees hrs Position 0 2 1 0 F 12 COOL AUTO 1 2 or OFF 2 1 1 1 F 24 COOL AUTO pa or 4 0 2
12. and cannot be adjusted The heating cycle rate be adjusted by turning one or both cycle rate adjustment screws located on the back of the thermostat In multistage heat systems the cycle rate adjustment applies to the highest stage of heat only Screws should be backed out about one half to one turn or be turned in until tight See Fig 15 68 0058 1 T8621A C D INSTALLATION Fig 15 Cycle rate adjustment gg apni SYSTEM GRAVITY OUT 1 2 OUT 1 2 AIRAWATER TO 1 TURN TO 1 TURN HOT WATER GAS OIL IN IN WARM AIR FACTORY SETTING OUT 1 2 TO 1 TURN A SCREWS 2A 2B AVAILABLE ON SOME MODELS ONLY M311A FAN OPERATION OPTION SWITCH SUPER TRADELINE models include a fan operation option switch on the subbase visible before the thermostat is mounted on the subbase The switch should be in electric heat position forelectric heating systems that do not have indepen dent fan control INSTALLING BATTERIES Three AAA alkaline batteries are included to provide backup to prevent program loss in case of power outage Install batteries in back of thermostat as shown in Fig 16 Withoutbattery backup the program will remain about 30 seconds in event of power loss IMPORTANT When batteries are first installed the display will flash 1 00 PM and 32 The temperature will stay at 32 F until the thermostat is powered from the system wiring When the batteries are low the display will flash
13. the following test as a check of all thermostat functions If thermostat does not respond as indicated thermostat must be replaced 1 Press AHEAD and BACK keys at the same time While holding keys down all segments of the display should be on see Fig 18 Fig 18 All segments on display 710 SET ROOM SUN MON TUE WED THU FRI SAT TEMPORARY MORNING MIDDAY EVENING NIGHT COOL ONHEAT ON M 525A ZUZI AM ELI LI Py s t LI 2 Set the system switch to OFF Press and release AHEAD and BACK and PRESENT SETTING keys at the same time to enter self test 3 Press each key as listed below and look for re sponses listed as key is held down and released System Press Look For This Response Switch This Key Position Key Down Key Released OFF CHANGE 03 Blank PERIOD 07 Blank PERIOD 15 Blank SETTING COOL or 15 15 stage cooling AUTO SETTING fan and SYSTEM with fan LED on in AUTO 15 ue kg cooling 15 2nd stage cooling SETTING off PRESENT 15 Ist stage cooling fan and SYSTEM LED off NOTE If single stage cooling system press key twice instead of 4 times once to turn cooling fan and SYS TEM LED on second time to turn off 18 System Press Look For This Response Switch This Key Position Key Down Key Released OFF 06 Blank COOLER 02 Blank 05 Blank AHEAD 04 Blank 01 Blank FROM 00
14. 40 A1238 C E1001 E1007 12464 E1050 A1261 E1126 1345 C G1009 G10258 B1004 B1038 B1079 A1005 1013 C1003 D1002 E1001 E1050 E1126 G1009 G10255 B1000 B1034 B1075 C1004 C1012 10204 C1038 C1087 C1350 C C1368 C1392 1400 C1566 C B1000 B1034 B1075 D1003 D1011 D1276 D1300 D1383 C Subbase 0412 A1006 A1113 C1004 D1003 E1002 G1000 B1005 B1070 B1146 A1006 A1113 C1004 D1003 E1002 G1000 B1005 B1070 B1146 A1006 1113 C1004 D1003 E1002 61000 B1005 B1070 B1146 A1006 A1113 C1004 D1003 E1002 G1000 B1005 B1070 1146 continued TABLE 3 18621 THERMOSTATS RECOMMENDED TO REPLACE T874 T872 OR T870 MODELS Continued T8621A C D SELECTION APPLICATION INSTALLATION Thermostat Subbase asa IJ Stages Included Thermostat Subbase Thermostat Subbase Thermostat Subbase Heat Cool T8621 T874 Q674 872 0672 T870 Q412 0 2 D7006 E1008 D1008 E1002 D1002 E1006 D1003 D7014 1016 01040 1010 G1009 E1014 G1000 D7097 E1107 G1005 1150 61025 E1030 G10218 G10708 2 0 C7008 F1007 D1008 F1001 D1002 F1005 D1003 7016 C F1015 D1040 1019 G1009 F1054 G1000 F1114 61005 F1100 C G10255 F1120 G10218 G1070 Disregard unused second st
15. 44 mm deep See Fig 1 for subbase dimen sions and Fig 2 for sensor dimensions TYPICAL KEYPAD See Fig 3 ACCESSORIES TG586A Locking Cover TG512 Versaguard Universal Thermostat Guard REPLACEMENT PARTS 202905AA Remote Temperature Sensor Assembly Includes sensor screws anchors and instructions See EHEu 2fordimensions C Fig 1 T8621 Subbase mounting dimensions in in mm 31 32 50 1 lt M5181A 35 83 3 43 121 gt 7 179 68 0058 1 T8621A C D SPECIFICATIONS SELECTION APPLICATION Fig 2 202905AA Remote Temperature Sensor dimensions in in mm FRONT SIDE BACK 32 50 51 2 a St 432 104 Honeywell M5244 Fig 3 Typical thermostat keypad SYSTEM Honeywell TEMPERATURE PRESENT PROGRAM SETTING X SET PRESENT DAY TIME PERIOD fee 5 gangs TEMP HEAT COOL PERIOD A PERIOD e e e HEAT OFF COOL M5360 T8621A C D SELECTION APPLICATION Selection A pplication The T
16. 8621 Thermostat uses the latest microelectronic design and control technology to provide home and building owners with the highest level of comfort available and optimal energy savings in a package that is easy to use and easy to live with The following section is a guide to selection and applica tion of the best thermostat to meet individual needs PROGRAMMING Does the thermostat selected accommodate the customer s daily schedule lifestyle or work schedule Refer to choices below ee a oe ee Daily Temperature Device Programming Selection 7 day each 4 heat and 4 cool day different 5 1 1 Mon Fri 4 heat and 4 cool Sat Sun Model not currently available to control multistage equipment IF NEW CONSTRUCTION APPLICATION CONSIDER Equipment type see manufacturer s specifications Staging required System switching required Fan switching required Contol wiring number of conductors required to operate equipment and thermostat IMPORTANT The T8621 requires an additional conduc tor to transformer common to provide continuous 24V power for thermostat operation IF RETROFIT REPLACEMENT APPLICATION CONSIDER Equipment requirements Staging heat stages cool stages System switching manual HEAT OFF COOL automatic HEAT AUTO COOL OFF Emer gency heat for heat pump application not provided T8621 Fan switching does fan come on automatically from thermo
17. AN 3 F DISPLAY FLASHES DURING PROGRAMMING HAS BEEN LOST REPROGRAM ACCORDING PROGRAMMING INSTRUCTIONS OPERATION BECAUSE OUTAGE MAKE SURE BATTERIES ARE INSTALLED 5234 29 68 0058 1 T8621A C D GLOSSARY Comfort temperature The temperature desired when active and occupying the building Energy saving temperature The lower heating or higher cooling temperature that allows savings on heating and cooling costs when asleep or away Also called the setback heating or setup cooling temperature Preprogrammed schedule This is the schedule programmed into the thermostat at the factory It sets a night program that provides energy savings when owner sets no program or if personal program is lost for any reason The program which is the same for all days of the week is Start Temperature Period Time Heating Cooling MORNING 6 00 AM 70 F 78 F MIDDAY No program EVENING No program NIGHT 10 00 PM 60 78 Program The times and temperatures owner sets to define the comfort and energy saving periods for each day schedule Recovery The time when the thermostat operates the heating or air conditioning equipment to return the building from the energy saving temperature to the comfort temperature The thermostat starts the recovery period early so the building will be at the comfort setting by the time the owner has chosen S
18. AT DOES NOT PROVIDE MINIMUM OFF TIME IN CABLE 200 ft 61 m MAXIMUM LENGTH ROUTE INTERCONNECT HEATING CABLE AWAY FROM SOURCES OF ELECTRICAL NOISE M1547C 13 68 0058 1 T8621A C D INSTALLATION Fig 13 T8621C D single stage heat pump with cooling changeover HEAT AUTO COOL OFF system and AUTO ON fan switching L1 HOT L2 A A SYSTEM 4 TRANSFORMER YL R lt lt HIGH LIMIT HIGH i LIMIT H COOLING wi L CHANGE SYSTEM SWITCH 2 lt HH 4 LOGIC CIRCUIT AUTO COMPRESSOR Z COOL CONTACTOR OFF 4 FAN RELAY RCUIT POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED ADD RELAY SPDT TO ACCOMMODATE COOLING CHANGEOVER gt gt tm APPLICABLE ONLY ON T8621D MODELS WITH REMOTE SENSOR A 202905 REMOTE L SENSOR LJ A RECOMMENDED INTERCONNECT CABLE 18 GAUGE THERMOSTAT CABLE 200 ft 61 m MAXIMUM LENGTH ROUTE INTERCONNECT CABLE AWAY FROM SOURCES OF ELECTRICAL NOISE A T8621D ONLY DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION NOTE SET CYCLE RATE TO HOT WATER SETTING 3 cph THERMOSTAT DOES NOT PROVIDE MINIMUM OFF TIME IN HEATING M1548C 14 Fig 14 T8621D single stage heat pump HEAT OFF COOL system and AUTO ON fan switching L1
19. ERCONNECT 1032 ee 68 0058 1 T8621A C D INSTALLATION Fig 9 T8621C 2 stage heat 1 stage cool thermostat with HEAT AUTO COOL OFF system and AUTO ON fan switching HEATING TRANSFORMER L1 HOT L2 HIGH LIMIT HIGH ME HEAT 1 HEAT RELAY 1 SYSTEM SWITCH THERMOSTAT LOGIC CIRCUIT Op 5 Z Z Z gt E HEAT RELAY 2 NH COOLING COOL CONTACTOR 019 2 EN FAN SWITCH FAN RELAY AUTO E ON A L1 HOT L2 COOLING A TRANSFORMER N POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD NOMINAL 24 Vac POWER MUST BE PRESENT BETWEEN R AND C FOR PROTECTION AS REQUIRED L THERMOSTAT OPERATION N FOR SINGLE TRANSFORMER SYSTEM JUMPER R AND RC N DENOTES THERMOSTAT SUBBASE INTERCONNECTION 5233 10 T8621A C D INSTALLATION Fig 10 T8621D 2 stage heat 2 stage cool thermostat with HEAT AUTO COOL OFF system and AUTO ON fan switching HEATING TRANSFORMER A L1 A 1 AS HOT lt LIMIT d A c lt VV HIGH LIMIT HEAT 1 HEAT RELAY 1 HEAT 2 SYSTEM SWITCH A Z r1 2 THERMOSTAT LOGIC CIRCUIT P lt an JJ COOL 2 BH e COOLING COOL 1 CONTACTOR 2 COOLING ux SUBBASE SWITCH CONTACTOR
20. G THE THERMOSTAT Program the EVENING time and tem p Press and release The display shows 9 perature if desired PERIOD EVENING but no time or temperature MON HEAT EVENING Press and hold until the display meri rne Iom DOLI shows the time the temperature should MONTES HEAT be at the comfort setting BACK Press and hold until the display shows CDM um the desired heating temperature won eat EVENING ag Program the NIGHT time and tempera Press and release The display shows ture if desired PERIOD NIGHT and the preprogrammed time and temperature Press and hold until the display shows the time to start the energy saving period Press and hold until the display shows the desired heating temperature 00 gt 2 E Q 22 E Set the cooling temperatures for all the SET Press and release The display shows TES periods programmed The program times HEAT COOL COOL the preprogrammed cooling won coo are the same for both heating and cool temperature and the programmed start ing Only the cooling temperatures need time for NIGHT to be programmed if programming has been completed for heating If you Bt Press and hold until the display shows change program times for cooling you WARMER the desired cooling temperature for are also changing the times for heating NIGHT COOLER i d If the display blinks while holding d
21. Honeywell T8621A C D Chronotherm III Fuel Saver Thermostats The T8621A C D Chronotherm III Program mable Fuel Saver Thermostats provide auto matic control of single or multistage heating cooling systems and offer users the highest standard of comfort and convenience available with energy savings Full seven day program capability different sched ules may be selected for every day W Can be programmed in hand with batteries in stalled or on wallto provide up to fourtemperature settings per day B Large digital clock liquid crystal display indi cates continuous time day current period and room temperature Adaptive Intelligent Recovery brings room temperature to programmed temperature at pro grammed time maximizing comfort and energy savings Temperature control program maintains tempera ture within 1 F of setpoint B Temporary program override available by using WARMER and COOLER keys SKIP next period key CHANGE to last period key B HOLD TEMP key provided for indefinite pro gram override vacation holiday Installer self test and time delay override save installation time B SYSTEM light emitting diode LED indicates system is energized Models available with automatic or manual heat cool changeover Batteries included provide power to maintain clock and memory during power failures Switching subbase with wiring terminals included W Powered dire
22. O ON AUTO HEAT AUTO COOL OFF jJ HEAT AUTO COOL OFF e HEAT AUTO COOL OFF TT HEAT AUTO COOL OFF Now read on to learn about the operating flexibility T8621A C D PROGRAMMING THE THERMOSTAT e OPERATING THE THERMOSTAT that makes this thermostat the smart choice TEMPORARILY CHANGING THE PROGRAM These features allow customizing the program for those times when someone comes home early is working late or planning to be out for the evening Changes made with these keys are ac tive for one program period and then are canceled To keep the current temperature through the next program period To go back to the temperature of the pre vious program period To temporarily raise or lower the tem perature for the current period only To change back REPROGRAMMING THE THERMOSTAT If schedule changes or a different tem perature is wanted update any setting without affecting the rest of the pro gram CHANGE TO LAST PERIOD This completes the programming of the thermostat If it was removed from the wall to program replace it following the proce dure on page 17 Operating the Thermostat Press and release The name of the period to be skipped will flash in the display until the start time of the skipped period During the skipped period the display will flash temporary to show that the programmed temperature for this period
23. S FOR CORRECT INCORRECTLY ON BASE gt MOUNTING PRESENT SETTING APPEARS NORMAL OPERATION THERMOSTAT TURNS ON INACCURATE gt THERMOSTAT IS IN RECOVERY MODE HEATING COOLING EARLY TO MEET TEMPERATURE SETTING AT PROGRAMMED TIMES RECOVERY CAN BE ENDED BY PUSHING WARMER COOLER KEYS ROOM TEMPERATURE DISPLAY THERMOSTAT HAS SEPARATE THERMOSTAT IS CONTROLLED BY TEMPERATURE APPEARS INACCURATE REMOTE MOUNTED SENSOR SENSED AT REMOTE SENSOR LOCATION lt CHECK TEMPERATURE AT REMOTE SENSOR LOCATION lt MAKE SURE WIRING FROM THERMOSTAT LOCATION TO REMOTE SENSOR LOCATION IS IN GOOD CONDITION REPROGRAM THERMOSTAT TO MAKE PERMANENT CHANGE IN PROGRAM WARMER COOLER KEYS ARE TEMPORARY UNLESS PERIOD KEY IS PRESSED FIRST THERMOSTAT TEMPERATURE NEEDS TO BE ADJUSTED ON A REGULAR gt BASIS WARMER COOLER KEYS BEING USED TO ADJUST TEMPERATURE PROGRAM IS LOST DUE TO POWER OUTAGE OR DISPLAY GOES BLANK WHEN POWER IS TURNED OFF BATTERIES ARE INCORRECTLY INSTALLED REMOVE AND REPLACE PER MARKINGS ON THERMOSTAT BATTERIES ARE DEAD _ REPLACE BATTERIES DISPLAY FLASHES WHILE CHECK PROGRAMMING INSTRUCTIONS FOR CORRECT PROGRAMMING IMPROPER PROGRAM SEQUENCE PROGRAM SEQUENCE AUTOMATIC THERMOSTAT HEATING OR COOLING TEMPERATURE GAN SET HEATING AND COOLING TEMPERATURES 3 F OR NOT BE SET CLOSER TH
24. XZ COOLING TRANSFORMER A L1 Ho N POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD amp FOR ELECTRIC HEAT APPLICATIONS AUTO FAN OPERATES WITH W1 PROTECTION AS REQUIRED AND Y1 USE ONLY ONE TRANSFORMER JUMPER R AND RC SET SWITCH TO ELECTRIC POSITION FOR GAS OR OIL APPLICATIONS OR ELECTRIC HEAT APPLICATIONS WHERE THE FAN OPERATION IS CONTROLLED INDEPENDENTLY OF NOMINAL 24 VAC POWER MUST BE PRESENT BETWEEN R AND C FOR THE THERMOSTAT AUTO FAN OPERATES WITH Y1 ONLY TWO THERMOSTAT OPERATION TRANSFORMERS MAY BE USED SET SWITCH TO NON ELECTRIC POSITION DENOTES THERMOSTAT TO SUBBASE INTERCONNECTION M1016C 12 T8621A C D INSTALLATION Fig 12 T8621C D single stage heat pump with heating changeover HEAT AUTO COOL OFF system and AUTO ON fan switching SYSTEM A TRANSFORMER P 97 NN lt HEATING H1 CHANGEOVER SAITOH COMPRESSOR gt HEAT E CONTACTOR THERMOSTAT 1 LOGIC CIRCUIT 2 AUTO gt COOL NS OFF SUBBASE FAN RELAY CONTROL CIRCUIT ON 202905 REMOTE SENSOR La POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD T8621D ONLY PROTECTION AS REQUIRED A K DENOTES THERMOSTAT TO SUBBASE CONNECTIONS ZA APPLICABLE ONLY ON T8621 MODEL WITH REMOTE SENSOR ES NOTE SET CYCLE RATE TO HOT WATER SETTING 3 cph RECOMMENDED INTERCONNECT CABLE 18 GAUGE THERMOSTAT THERMOST
25. Y _ NO ac POWER THERMOSTAT _ CHECK POWER TO FURNACE OR AIR CONDITIONER IS 2 EE ON OFF SWITCH FUSE OR CIRCUIT BREAKER LOOSE 24 V CONNECTION AT THERMOSTAT AT FURNACE AIR CONDITIONER INCORRECT WIRING CHECK WIRING DIAGRAM FURNACE OR AIR CONDITIONER WON T OPERATE p NO ac POWER TO THERMOSTAT I CHECK POWER TO FURNACE OR AIR CONDITIONER ON OFF SWITCH FUSE OR CIRCUIT BREAKER LOOSE 24 V CONNECTION THERMOSTAT AT FURNACE AIR CONDITIONER INCORRECT WIRING CHECK WIRING DIAGRAM L THERMOSTAT INOPERATIVE CONDUCT SELF TEST SEE CHECKOUT PRESENT SETTING LOW HIGH One ENS WAR MEN SYSTEM SWITCH ON THERMOSTAT gt iN WRONG POSITION gt RESET THERMOSTAT SYSTEM SWITCH MINIMUM OFF TIMES IN THERMOSTAT WAIT 5 10 MIN OR USE SELF TEST IN THERMOSTAT IN OPERATION ON COOLING gt SEE CHECKOUT I INCORRECT WIRING I CHECK CIRCUIT DIAGRAM CONSULT FURNACE OR AIR CONDITIONER FURNACE OR AIR CONDITIONER gt INOPERATIVE INSTRUCTIONS PARTIAL DISPLAY gt INOPERATIVE THERMOSTAT gt REPLACE THERMOSTAT NO DISPLAY NO POWER TO THERMOSTAT p CHECK THAT HEAT OR COOL SYSTEM POWER IS ON THERMOSTAT MOUNTED SEE INSTALLATION INSTRUCTION
26. age terminals on T8621 replacement Disregard heating system switch positions and wiring terminals W1 W2 on T8621 replacement Jump RC RH for thermostat power Disregard cooling system switch position and wirin g terminal 1 on T8621 replacement Jump RC RH if manual fan control G terminal is desired 8 Temperature restriction and or locking cover provided with T874 T872 T870 accessory TG501 Lockin g Guard may be used with T8621 replacement Device built to DoD specifications accessory TG501 Locking Guard may be used with T8621 replacement 12 F heating interstage differential to provide night setback T8621A7002 replacement sets back first stage automatically O B changeover terminals not provided on T8621 replacement Includes separate sensor for remote temperature sensing Installation COMPATIBILITY The 18621 Thermostats will replace most heating cool ing system thermostats As long as ac power is continuously available to the transformer the thermostat will be com patible with any low volt control system N CAUTION Disconnect power supply to prevent electrical shock or equipment damage LOCATION Thermostat with Integral Sensor Instali thermostat and subbase about 5 ft 1 5 m above the floor inan area with good air circulation atroom temperature Do not install thermostat where it may be affected by drafts or dead spots behind doors in corners or under cabinets hot or cold air from ducts
27. because family members are asleep or the building is unoccupied Often a NIGHT energy savings temperature is set only for the heating season so family members can sleep cool in summer T8621A C D TABLE OF CONTENTS Table of Contents page NAN PEGA NENGNA KG Na ANGEN ga Pap a a ap Nak a Tapas ga ee anapa 2 Ordering Information 2 erinnere e eee ern eoe BR Rae a ata GD 2 Selecion Appi CaO ee ARR e UR te m ae crie a tosis wanton AKA NG ea BG nec ione aa a 3 Installation o eet ee eom nere etd avec pO eve E ee d ira ete dee gn 7 Compatibilitys i aaa ertet evi RR ei e Er pce bee tns 7 S tiere aot epe ciii eme oce ctu eene pel 7 Mounting Subbase a nro ere det n e e RE E rc D SHE tbe Aet reto svete Eripe e A ERES 8 Mounting Remote Temperature Sensor essere nennen NEKENG EES Ee E SEEE neor Es SE keD Ene ere ee 8 Wiring iiid eoi tei e i REP TET 9 Adjusting Cycle Rate em er et ed kaa Se bu Ister as es 15 Time Temperature COnVersion 5 rettet pron Repo dr NGE NG Y Pe etii re E E heir 15 Fan Operation Option Switch abe de eot QU aeree rete De oe ter BK Ba ED saa Rte re qp ens 16 Installing Batteries 3 a tere Rp RT ear eem i petenti m ah iphu aes layed 16 Power OULA BES oet oie i E UO D e reme nieder edit
28. ctly from control transformer requir ing an extra 24V wire to thermostat Fanoperation switch included on back of SUPER TRADELINE models to select either indepen dent or direct thermostat control of fan in heating B Models available with separate sensor for remote mounting CONTENTS Spe eficqtions m eO 2 Ordering Information 2 Selection Application 5 Installation 2 Z CHECKOUT ya 17 Programming the Thermostat 19 Operating the Thermostat 25 2 2 26 Troubleshooting nn KN 29 30 Tablero RS 31 4 2 OOM Rev 8 92 OHoneywell Inc 1992 Form Number 68 0058 1 T8621A C D SPECIFICATIONS e ORDERING INFORMATION Specifications IMPORTANT The specifications given in this publica tion do not include normal manufacturing toler ances Therefore this unit may not exactly match the listed specifications Also this product is tested under closely controlled conditions and some minor differences in performance can be expected if those conditions are changed SUPER TRADELINE MODEL SUPER TRADELINE controls see Table 1 offer fea tures not available on TRADELINE models and are designed to replace a wide range of Honeywell and competitive controls SUPER TRADELINE FEATURE Fan operation switch on back of thermostat to select either independen
29. e ge 16 Mounting the Thermostat et eere eco aeree ire eae ae He ie ete rete eed 16 Settime Dayan EB a 16 Checkout iion eR DR er RE detener BEP e i 17 Fieatineu su EE HE 17 COON as hq Su Su Q 17 Fan tenete pue RU e D e UR RDDO e 17 Installer Self Test i noe et terat paskaspa ete 18 Programming the Thermostat ue erede ehe pede 19 Enter the Day and Time onere ee eo b EE ette shahih PU EUM a EUER AS ees 19 Set the Program Times and Temperatures for One 20 Copy the Program to the Desired Days us s s eo eee et e UU o Re e ERIS 22 Set the Schedules and Temperatures For the Remaining 23 Set the System and Fan Switches on the Subbase oo eee cscecseeeeeeecseeeseeseeeseeeeeeesecesecaecsaecsaecaeeaeeseseaseaeeeneeegs 24 Operating the Thermostat u a aee Iam eremi te e ER RR 25 Temporarily Changing the Progra eee eter sia Rd et rediere pe ip este LR 25 Reprogramming the Thermostat au NA NS ARA THE Ga TA nennen trennen tren teen AN NO TEN tenere tenere tenen en 25 Holding a Temperature for Extended Absence sese nennen nenne ener anara nane nentes 26 Canceling Program Settings eee eh iat eet teh IE Gp E AEN ei M Lee
30. egardless of weather conditions occupants come home and wake up to comfort Drafts from low temperature discharge air are mini mized during occupied periods Comfort and energy savings can be achieved in both heating and cooling When Adaptive Intelligent Recovery is Used Adaptive Intelligent Recovery is used during recov ery from energy savings It is bypassed when the setpoint is changed and when the CHANGE TO LAST PERIOD SKIP NEXT PERIOD or HOLD TEMP key is pressed If Adaptive Intelligent Recovery is bypassed the system operates the stages of equipment like a conventional thermostat WHAT TO EXPECT DURING RECOVERY FROM ENERGY SAVINGS IN HEATING The T8621 controls the heating equipment based on the indoor sensed temperature which is a combination of air 28 Operation temperature and wall temperature THERMAL PERFORMANCE WITH T8621 During severe weather the T8621 actually controls closer to the setpoint than a conventional thermostat This is because the heat anticipator is replaced by two elec tronic control strategies cycling by heat anticipation and proportional plus integral control Electronic cycling by heat anticipation acts like a tradi tional heat anticipator except that it never needs adjusting for various control circuit load currents It cycles the heating system off slightly before the room temperature reaches the setpoint to keep heat remaining in the ductwork from overheating the room
31. el some of the switch positions shown may not be available Note the positions provided on subbase then set the switch es as desired First set the fan switch Then set the system switch RAM Press and release the COPY FROM key to enter the copy mode The next day flashes on the display Press and release the COPY TO key to select the day that is flashing or the DAY key to bypass it Continue using the COPY TO key to bring up the next day followed by COPY TO to select or DAY to bypass the day until all desired days are selected Press and release RUN PROGRAM to complete the copy Repeat Step 4 as needed until all days are programmed FAN ON The fan runs continuously Use for improved air circulation during special occasions or for more efficient electronic air cleaning FAN AUTO Normal setting for most homes and businesses The fan goes on and off with the air conditioner in sum mer n winter the fan on most systems Starts a few minutes after the furnace comes on It stops a few minutes after the furnace goes off The fan starts and stops with the furnace in some electric heat systems HEAT The thermostat controls the heat ing system AUTO The thermostat controls either the heating or air conditioning system depending on room temperature COOL The thermostat controls the air conditioning system OFF Both the heating and air condi tioning systems are off 24 ON AUT
32. etback Reducing the temperature in the building for a set period in heating for energy savings The lower tempera ture is the energy savings temperature 30 Glossary Setup Raising the temperature in the building for a set period in cooling for energy savings The higher temperature is the energy savings temperature Setpoint The thermostat temperature setting the owner selects The thermostat turns the heating or cooling equipment on and off to maintain this temperature at the thermostat location until another temperature setting setpoint goes into effect SYSTEM light This light glows whenever the thermostat is calling for heating or air conditioning Time period One of four program periods MORNING MIDDAY EVENING and NIGHT available with the Chronotherm III Thermostat one period begins when the previous program period ends MORNING The time period when the owner brings the building to a comfortable temperature to begin the day This is the only period that must contain a time and temperature for each day MIDDAY The time period when the owner can set back heating or setup the cooling temperature for day time energy savings if the building is unoccupied EVENING The time period when the owner wants the building at a comfortable temperature for evening activities after daytime energy savings NIGHT The time period when the owner can setback heating or setup the cooling temperature for energy savings
33. event drafts from affecting thermostat operation NOTE Restrict wiring to recessed area surrounding termi nals Fig 7 to assure thermostat subbase contact Refer to Figs 8 14 for typical hookups of subbase and thermostat T8621A C D INSTALLATION Fig 7 Restrict wiring to recessed area sur rounding terminals FOR STRAIGHT INSERTION STRIP 5 16 in 8 mm FOR WRAPAROUND STRIP 7 16 in 11 mm RESTRICT WIRING TO THIS AREA FRONT VIEW OF TERMINAL AREA TOP SURFACE WIRING TO BE BELOW OF SUBBASE THIS SURFACE CROSS SECTIONAL VIEW OF TERMINAL AREA 12 308 Fig 8 T8621A 1 stage heat 1 stage cool thermostat with HEAT AUTO COOL OFF system and AUTO ON fan switching THERMOSTAT LOGIC CIRCUIT SUBBASE LOGIC CONTROL CIRCUIT POWER SUPPLY PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED FOR SINGLE TRANSFORMER SYSTEM JUMPER R AND RC gt gt gt NOMINAL 24 Vac POWER MUST BE PRESENT BETWEEN R AND C FOR THERMOSTAT OPERATION HEATING TRANSFORMER A SYSTEM SWITCH 202905 REMOTE SENSOR E umanan vem ss ce x COOLING CONTACTOR SWITCH COOLING A TRANSFORMER APPLICABLE ONLY ON MODEL WITH REMOTE SENSOR J RECOMMENDED INTERCONNECT CABLE 18 GAUGE THERMOSTAT CABLE 200 ft 61 m MAXIMUM LENGTH ROUTE INTERCONNECT CABLE AWAY FROM SOURCES OF ELECTRICAL NOISE M DENOTES THERMOSTAT TO SUBBASE INT
34. is not being used Press and release The display will show the name of the previous period and flash temporary until the next regu larly scheduled period starts Press and hold until the desired tem perature is reached The display will flash temporary until the next pro grammed time period starts Press and release to cancel any of the tem porary settings Press and hold until the desired time period shows on the display Press and hold until the desired sched ule day shows on the display 25 68 0058 1 T8621A C D OPERATING THE THERMOSTAT Press and hold the Time or Temperature keys until the display shows the desired new program gt 0 A Copy the new program into other days COPY Press and release The next day will if desired When copying a program all FROM flash on the display Press COPY TO the times and temperatures for that day to copy into or DAY to bypass the are copied day Continue until the program has been copied into all desired days RUN Press and release to return to normal operation HOLDING A TEMPERATURE FOR EXTENDED ABSENCE Press and release This feature is particularly useful when going on vacation or other extended absence It does not cancel the program Press and hold to change the temperature setting After a few seconds the display will show the current temperature O PRESENT Press and release to check the tempera
35. ming mode Press and hold until the day containing the program to be copied shows in the display Press and release The day to be copied will show and the next day will flash in the display Press and release to copy the program into the day that is flashing in the display Note that the next day now starts to flash Press and release if it is not desired to copy into the day that is flashing Note that the next day now starts to flash 22 Utt AM 119 tL UD MO COOL MORNING 0AM 7009 ULU LI UR MON COOL MORNING CC une Ft nt UP MON COOL MIDDAY KANA QTO 10 120 MON COOL MIDDAY r n rn une LO PM MO COOL EVENING nr r9 LU PM N COOL EVENING Z Lig la MON HEAT MON TUE MON TUE MON TUE THU NOTE The display will show 32 F instead of the current temperature until the thermostat is mounted on the subbase and the system is pow ered STEP 4 SET THE SCHEDULES AND TEMPERATURES FOR THE REMAINING DAYS Use the procedures described in Steps 2 and 3 and summarized in this step to program the remaining days RUN PROGRAM HEAT COOL m gt 4 lt w gt T8621A C D PROGRAMMING THE THERMOSTAT Press and release the COPY TO key again to select the day that is flashing or the DAY key to bypass it Continue until all desired day
36. mpressor applications both first stage heating and first stage cooling energized through the Y terminal simply jumper Y 1 and 2 Note that the recovery algorithm of the T8621 may cause the compressor to cycle on and off during recovery Although the cycle rate for the first stages of heat and cool are set for hot water systems the second stage of the T8621 mustbe adjusted Turn the cycle rate adjustment screws to the hot water setting on both the T8621C and D to achieve the cycle rate appropriate for heat pumps If changeover is utilized in the cooling mode apply a normally closed relay as shown in Fig 12 The above application should be used onlyon single stage heat pumps 68 0058 1 T8621A C D SELECTION APPLICATION TABLE 3 T8621 THERMOSTATS RECOMMENDED TO REPLACE T874 T872 OR T870 MODELS Stages Heat 1 Thermostat Subbase Included A7002 7010 O A7044 D7022 D7006 D7014 D70973 D70223 C7008 C7016 D7022 D7006 D7014 C D70973 D7022 A1002 1010 1036 1150 1226 O A1176 B1001 B1019 B1068 C C1000 C1018 C1125f C1141 C1240 C D1009 D1017 D1132 C D1165 D1223 C 1231 Thermostat T872 T870 A1001 1006 A1005 A1019 10144 A1013 C10098 A1030 C1003 D1008 A1048 D1002 D10
37. ntil they are flush with the wall surface Thread wires through the center opening of the subbase Then mount the subbase using two screws provided Gently tighten screws level top surface of subbase and securely tighten screws Fig 5 Mounting subbase on wall WALL WIRES THROUGH WALL OPENING MOUNTING MOUNTING SCREWS 2 12207 MOUNTING REMOTE TEMPERATURE SENSOR IF APPLICABLE Theremote sensor mounts directly on the wall with screws and anchors included Remove cover from remote sensor Fig 6 Use the remote sensor base as a template and with a pencil mark holes for mounting screws Use a 3 16 in bit to drill the required holes Gently tap anchors into holes until they are flush with the wall surface Thread wires through the opening in the base Mount remote sensor base using the screws provided See Fig 6 Make sure base looks level before tightening screws Fig 6 Mounting remote sensor base on wall REMOTE SENSOR COVER WIRING HOLE SD REMOTE SENSORBASE P MOUNTING 15498 SCREWS 2 WIRING All wiring must comply with local electrical codes and ordinances Disconnect power before wiring to prevent electrical Shock or equipment damage The shape of the terminal barrier permits insertion of straight or conventional wraparound wiring connections Either method is acceptable Push excess wire back into the hole and plug hole with nonhardening caulk putty or insulation to pr
38. or that period Press and release to return to normal operation Press and release The display will show the current temperature setting for sev eral seconds then revert to the room temperature During recovery from energy savings the setting displayed will not match the programmed setting This is because the thermostat gradually changes the temperature setting during recovery to provide maximum comfort combined with most efficient use of the heating or cooling equipment 27 rer k Pa FRI EVENING sr 280 68 0058 1 T8621A C D OPERATION ADAPTIVE INTELLIGENT RECOVERY OPERATION Adaptive Intelligent Recovery is the Honey well trade mark for the way the T8621 controls the heating and cooling equipment during recovery from an energy sav ings setting to a comfort setting During recovery the control point changes gradually rather than jumping from the energy savings setting to the comfort setting all at once This provides additional energy savings In both heating and cooling the thermostat monitors recovery each day and adjusts the next day recovery start time This ensures that the building is at the desired temperature at the programmed time regardless of the outdoor temperature Recovery time varies depending on the weather conditions and the building heating cooling system The advantages are e Comfort setting is achieved at the programmed time and maintained r
39. own TEMPERATURE WARMER or COOLER the setting limit has been reached If thermostat can switch auto matically between heating and cooling the heating temperature must be at least 3 degrees F below the air conditioning temperature For example if the heat ing setting is 72 F the minimum cool ing set ting is 75 F To set the cooling temperature lower first lower the heat ing setting 21 68 0058 1 T8621A C D PROGRAMMING THE THERMOSTAT STEP 3 COPY THE PROGRAM TO THE DESIRED DAYS It is possible to copy the program for one day to any other day or combination of days The new program will replace any program already set in the day se lected Press and release The display shows the preprogrammed cooling tempera ture and the programmed start time for MORNING Press and hold until the display shows the desired cooling temperature for MORNING Press and release The display shows the preprogrammed cooling tempera ture and the programmed start time for MIDDAY Press and hold until the display shows the desired cooling temperature for MIDDAY Press and release The display shows the preprogrammed cooling tempera ture and the programmed start time for EVENING Press and hold until the display shows the desired cooling temperature for EVENING This completes the program schedule for one day Go to Step 3 to copy this program to additional days If necessary press and release to enter the program
40. rincipal cities of the world Manufacturing in Australia Canada Finland France Germany Japan Mexico Netherlands Spain Taiwan United Kingdom U S A T8621A C D SPECIFICATIONS TABLE 2 TRADELINE MODELS Thermostat Model Stages Changeover Switching Number Heat Cool Type System Fan Application T8621A 1 1 Auto HEAT AUTO ON AUTO Single stage COOL OFF T8621C 2 1 Auto HEAT AUTO ON AUTO Multistage COOL OFF T8621D 2 2 Auto HEAT AUTO ON AUTO Multistage COOL OFF Model available with separate sensor for remote mounting CURRENT RATING 1 6A maximum total per stage OPERATING HUMIDITY RANGE 5 to 90 percent relative humidity noncondensing OPERATING AMBIENT TEMPERATURE RANGE 40 F to 110 F 4 C to 43 C SETPOINT RANGE 45 F to 88 F 7 C to 31 C CALIBRATION Self calibrating thermostat and ther mometer to 1 F SHIPPING TEMPERATURE 20 F to 120 F 29 C to 449 C CYCLES PER HOUR ADJUSTMENT Heating First stage of 2 stage heat models fixed at 3 cph Second stage of 2 stage heat models or heat stage of single stage heat models factory set at 6 cph adjustable for other systems Cooling Factory set at 3 cph not field adjustable minimum off time of five minutes FINISH Beige matte with decorative brushed metal face plate DIMENSIONS Thermostat mounted on subbase 7 in 178 mm long 5 5 16 in 135 mm high 1 3 4 in
41. s are show ing in the display and are not flashing If an error is made in copying start over by pressing COPY TO key re peatedly until all days are shown NOT flashing press COPY TO key once more Press and release to copy the program into all the days selected Press and release to enter the program ming mode Press and hold until the day desired to program shows on the display If COOL shows on the display press and release to switch to HEAT Use the AHEAD BACK keys to set the time and the WARMER COOLER keys to set the heating temperature Press and release the PERIOD key to step through the remaining time peri ods Use the AHEAD BACK keys to set the time and the WARMER COOLER keys to set the heating tem perature for each time period Press and release so COOL shows on the display Press and release the PERIOD key to step through the time periods and use the WARMER COOLER keys tosetthe cool ing temperature for each period This completes the time and tempera ture program for another day Copy it into additional days if desired 23 MON TUE THU FRI TUE MIDDAY FRI HEAT MIDDAY MORNING 68 0058 1 T8621A C D PROGRAMMING THE THERMOSTAT NOTE The display will show 32 F until the thermostat is mounted on the sub base and the system is powered STEP 5 SET THE SYSTEM AND FAN SWITCHES ON THE SUBBASE Depending on thermostat mod
42. st 3 F 2 C above the heating temperature or display will flash N S CAUTION Do not operate cooling if outdoor temperature is below 50 F 10 C Refer to manufacturer s recommendations 17 Checkout NOTE When cooling setting is changed thermostat will wait up to five minutes before turning on the cooling equipment This delay is to protect the compressor Move the system switch to COOL and the fan switch to AUTO Press COOLER key until the setting is about 10 F 6 C Below room temperature The cooling equipment and fan should start both stages if multistage Press WARMER key until the setting is about 10 F 6 C above room temperature The cooling equipment and fan should stop NOTE On an AUTO changeover thermostat the heating temperature must be set at least 3 F 2 C below the cooling temperature or display will flash FAN Move the system switch to OFF and the fan switch to ON The fan should run continuously When the fan switch is in the AUTO position fan operates directly with the thermostat call for cooling and also with the thermostat call for heating 68 0058 1 T8621A C D CHECKOUT INSTALLER SELF TEST OPTIONAL IMPORTANT 1 Thermostat must have ac power to perform self test Relays will not toggle codes will not be present and thermostat will not manually exit self test without ac power 2 Five minute time delay on cooling does not function during self test Perform
43. stat on cooling only typical gas oil heating or on call for cool and heat typical electric heat with single speed fan Existing wiring Are there enough conductors to operate the equipment and the thermostat Can a new cable be pulled IMPORTANT The 78621 requires an additional conduc tor to transformer common to provide continuous 24V power for thermostat operation e Existing thermostat For a guide for replacing popular Honeywell stan dard nonprogrammable thermostats with T8621 see Table 3 SECURITY Does the thermostat selected provide access to pro grammming and the override features that will best suit the application Refer to choices below Typical Access Application Device Free access to Home or T8621A C D programming owner occupied and adjustment commercial override building Restricted Public T8621 with TG512 access to building Locking Guard or device TG586A Locking Cover T8621 with remote temp erature sensor SINGLE STAGE HEAT PUMPS If home building owner hasa single stage heat pump option is to use a T8621C or D see Figs 11 13 The T8621C is a two stage heating one stage cooling programmable thermostat The T8621D is a two stage heat ing two stage cooling programmable thermostat What both thermostats have in common is separate W 1 and W2 firstand second stage heat terminals In both cases the WI can be used for changeover in heating For single stage co
44. t or direct thermostat control of fan in heating TRADELINE MODELS TRADELINE models see Table 2 are selected and pack aged to provide ease of stocking and handling and also maximum replacement value LIGHT EMITTING DIODE LED SYSTEM LED lights during thermostat ON cycle VOLTAGE RATING 15 to 30 Vac TABLE 1 SUPER TRADELINE MODEL Thermostat Model Stages Changeover Switching Number Heat Cool Type System Fan Application T8621D 2 2 Manual HEAT OFF COOL ON AUTO Multistage Ordering Information When purchasing replacement and modernization products from your TRADELINE wholesaler or distributor refer to the TRADELINE Catalog or price sheets for complete ordering number or specify 1 Model number SUPER TRADELINE if desired 2 Number of heat and cool stages desired 3 System fan switching desired 4 Remote temperature sensing if desired 5 Application If you have additional questions need further information or would like to comment on our products or services please write or phone 1 Your local Honeywell Home and Building Control Sales Office check white pages of your phone directory 2 Home and Building Control Customer Satisfaction Honeywell Inc 1885 Douglas Drive North Minneapolis Minnesota 55422 4386 612 951 1000 In Canada Honeywell Limited Honeywell Limitee 740 Ellesmere Road Scarborough Ontario MIP 2V9 International Sales and Service offices in all p
45. w seconds then begin to flash on and off Set present day and time Press mien Press to set the current day Each press of the DAY key advances the display one day Press TIME or tO set the current time If the display will not come on check the mounting of thermostat to subbase If Joose or misaligned remove thermostat and reinstall on the subbase making sure it is firmly attached check to see that heat or cool system power is on check voltage between R and C it should be 24 to 30 Vac Fig 17 Mounting thermostat on subbase 7 en Dooececge 2 T8621A C D INSTALLATION e CHECKOUT M 843 HEATING Move the system switch to HEAT and the fan switch to AUTO Press WARMER key until the setting is about 10 F 6 C above room temperature Heating should start both stages if multistage and the fan should run may be a short delay on forced air systems Press cooler key until the setting is about 10 F 6 C below room temperature The heating equipment should shut off followed by the fan NOTE On an AUTO changeover thermostat the cooling temperature must be set at lea

Honeywell CHRONOTHERM T8621A User's Manual

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