Honeywell ST9141A1002 User's Manual
Contents
1. EAC S EAC N Vnum gt ELECTRONIC AIR CLEANER lt 2 gt CIRCULATING FAN MED LOW COMBUSTION AIR BLOWER N3 120 VAC TRANSFORMER BURNER LIMIT PRIMARY LIMIT ST9141A ELECTRONIC FAN TIMER ITHERMOSTA PRESSURE SWITCH COOLING CONTACTOR SV9500 HOT SURFACE PILOT IGNITION SYSTEM CONTROL TSTAT FT NOTE DOTTED LINES REPRESENT PRINTED CIRCUIT BOARD WIRING m5608 3 69 0780 Setting the Heat Fan Off Delay DIP Switches Set the heat fan off delay DIP switches to 60 100 140 or 180 seconds as shown in Fig 3 The off delay is factory set at 140 seconds This delay time starts when the main gas valve is de energized at the end of a thermostat call for heat Checkout Assure the system operates properly by operating the system through at least one complete heating cycle and cooling cycle Troubleshoot by checking for appropriate voltages at the ST9141A1002 terminals controlling the combustion air blower and heat and cool speed circulating fan The ST9141A1002 schematic shows internal switch ing to clarify operation and assist in troubleshooting See Fig 2 ST9141A1002 Operating Sequence Fig 3 Setting delay off DIP switches ST9141 Honeywell n 60 SECONDS 100SECONDS 140 SECONDS 180 SECONDS DELAY OFF DIP SWITCH SETTINGS M2. 5658 Action System Response Thermostat calls for heat e Pressure switch confirmed in no airflow position If pressure switch shows W terminal is energized airflow LED flashes three times Combustion air blower is energized Air proving switch makes air flow is established Ignition system is energized Gas valve opens and main burner lights Heat fan on delay timing begins When timing is complete circulating blower is energized at heat speed Thermostat ends call for heat W terminal is de energized Thermostat begins call for cool G and Y terminals are energized Ignition system is de energized and gas valve closes Combustion air blower is de energized after postpurge timing Heat fan off delay timing begins When timing is complete the circulating fan is de energized Cooling contactor is energized Circulating fan is energized at cool speed after cool fan on delay timing Thermostat ends call for cool Y terminals are de energized Cooling contactor is de energized Circulating fan turns off after cool fan off delay timing Thermostat begins call for fan G terminal is energized Circulating fan is energized at heat speed two seconds after G terminal is energized If a call for heat occurs circulating fan continues to run at heat speed If a call for cool occurs circulating fan switches to cool speed after four second delay Thermostat en
3. Honeywell ST9141A1002 Electronic Fan Timer Application The ST9141A1002 Electronic Fan Timer integrates con trol of all combustion blower and circulating fan operations in a gas warm air appliance This control is the central wiring point for most of the electrical components in the furnace The basic purposes of the ST9141A1002 are to monitor the thermostat for heat cool and fan demands and run the induced draft blower motor and up to a two speed circulating fan as required The ST9141A1002 monitors an spdt pressure switch burner limit and primary limit A Honeywell SV9500 Hot Surface Pilot Ignition System Control manages the burner which is energized through the pressure switch A light emitting diode LED indicates system status In addition this model includes electronic air cleaner and humidifier convenience terminal connections NOTE Use this control to replace an identical ST9141A 1002 Electronic Fan Timer only This control is not for use in general applications Specifications ELECTRICAL RATINGS Power Requirements Voltage 18 30 Vac 60 Hz Contact Ratings Combustion Blower 1 5A Full Load 10A Locked Rotor at 115 Vac 75 Full Load 5A Locked Rotor at 230 Vac Reduce full load rating by humidifier load Circulating Fan Heat Cool Speed 15A Full Load 30A Locked Rotor at 115 Vac 7 5A Full Load 15A Locked Rotor at 230 Vac Reduce full load rating by electronic air cleaner load Thermostat Lo
4. ad 0 06A plus ignition system current draw ON OFF DELAY SETTINGS Heat Speed Delay On 30 seconds fixed Delay Off 60 100 140 or 180 seconds field adjustable Cool Speed Delay On 6 seconds fixed Delay Off 60 seconds fixed Timing Tolerance Larger of 5 or 2 seconds POSTPURGE TIMING 5 seconds ENVIRONMENTAL RATINGS Temperature 40 to 175 F 40 to 79 C Humidity 5 to 95 noncondensing LIGHT EMITTING DIODE LED INDICATIONS LED flashing dim bright indicates normal operation LED off when control is powered indicates defective control LED on continuously when control is powered indicates defective control LED flashing in a cycle with LED on followed by one or more off pulses indicates the following system errors Number of Off Flash Pulses System Condition 1 Burner limit circuit is open 2 Primary limit circuit is open 3 Pressure switch circuit is improp erly closed 4 Control is in lockout due to air not circulating overheating Installation WHEN INSTALLING THIS PRODUCT 1 Read these instructions carefully Failure to follow them could damage the product or cause a hazardous condi tion 2 Check the ratings and specifications given in the instructions and on the product to ensure the product is suitable for your application 3 Installer must be a trained experienced service technician 4 After installation is complete check out the product operation
5. as provided in these instructions N CAUTION Disconnect power supply before wiring to pre vent electrical shock or equipment damage Location and Mounting The ST9141A1002 is mounted in the appliance wiring compartment using four No 6 screws obtained locally through holes on the corners of the enclosure Wiring All wiring must comply with local codes and ordi nances Disconnect power before making wiring connec tions Refer to Fig 1 for standard wiring connections Refer to Fig 2 for an internal schematic G OER NP C H 6 93 OHoneywell Inc 1993 Form Number 69 0780 Fig 1 Typical ST9141A1002 wiring connections HUMIDIFIER L1 H 120 vac POWER SUPPLY L2 N AIR CLEANER COMBUSTION BLOWER PRIMARY LIMIT BURNER LIMIT SV9500 HOT SURFACE PILOT IGNITION SYSTEM CONTROL CIRCULATING ST9141 FAN PRESSURE SWITCH THERMOSTAT 998 COOLING CONTACTOR 24 VOLT COMMON 24 VOLT HOT EFT 24 VOLT NOTE DENOTES STANDARD TERMINAL THERMOSTAT OR PRESSURE DENOTES TERMINAL NOT PROVIDED DENOTES LINE VOLTAGE CONNECTIONS DENOTES LOW VOLTAGE CONNECTIONS Fig 2 ST9141A1002 internal schematic TO 120 VAC POWER SUPPLY INTERLOCK
6. ds call for fan terminal is de energized Circulating fan is de energized Primary limit switch string opens Thermostat and ignition system de energized and gas valve closes Combustion air blower is de energized Circulating fan is energized at heat speed LED flashes twice If there is a call for cooling or fan the circulating fan switches from heat speed to cool speed continued ST9141A1002 Operating Sequence Continued Action System Response Primary limit switch string closes Circulating fan turns off after the selected heat fan off delay timing LED stops flashing Normal operation resumes Primary limit switch string is open for more than 150 seconds on each of three consecutive cycles Combustion air blower circulating fan and ignition system are de energized Control goes into lockout mode LED flashes four times Control remains in lockout until 24V power is removed and reapplied control is reset LED stops flashing Normal operation resumes Burner limit opens Thermostat and ignition system are de energized and gas valve closes Combustion air blower and circulating fan heat speed are energized LED flashes once Burner limit closes Combustion air blower remains energized for postpurge timing The circulating fan remains energized for the selected delay off timing LED stops flashing Normal operation resumes Electronic air cl
7. eaner is connected Connector to 120 Vac electronic air cleaner Electronic air cleaner is energized when the circulating fan heat or cool speed is energized Humidity control is connected Connector to 120 Vac humidifier Humidifier is energized when combustion air blower is energized 5 69 0780 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 Honeywell Limit e 740 Ellesmere Road Scarborough Ontario MIP 2V9 Helping You Control Your World QUALITY IS KEY
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