Honeywell AQUASTATIC L7224 User's Manual
Contents
1. See Table 1 for a description of the error and suggested actions See below for a troubleshooting guide Table 3 Troubleshooting Guide System Diagnostic Condition Condition Check Action Boiler is Display is OFF 120 Vac system Turn system power on cold power house is Display is ON 24 Vac T T No 24V replace cold TT LED is OFF control Display is ON 24V present Boiler starts check TT LED is OFF disconnect wiring and thermostat thermostat short T T a Refer to Fig 5 for Display and LED locations b ZC LED ON indi cates ZC terminal power is OFF c ZC LED OFF indicates ZC terminal power is ON 3 69 1957 1 Table 3 Troubleshooting Guide System Diagnostic Condition Condition Check Action Boileris Display is ON 120 Vac at B1 If no replace control cold TT LED is ON B2 e If yes check burner house is B1 LED is ON and wiring cold Display is ON Refer to err on TT LED is ON display Boiler is Display is ON 120 Vac at C1 e 120 Vac at C1 C2 hot house TT LED is ON C2 check wiring to pump is cold C1 LED is ON e Wiring ok is pump running If not replace the pump If pump is running check for trapped air or closed zone valves Display is ON Boiler below the TT LED is ON Low Limit C1 LED is OFF temperature ZC LED is ON wait for boiler to go above Low Limit temperature Display is ON Boiler above e If no 120 Vac TT2. Honeywell L7224 Series Oil Electronic Aquastat Controller TECHNICIAN S QUICK REFERENCE GUIDE The following service procedure provides a quick overview for L7224 Series Controllers For more information refer to form 69 1384 On the L7224U the High Limit High Limit Differential Low Limit and Low Limit Differential can be adjusted to the settings recommended by the boiler OEM Adjusting Settings To discourage unauthorized changing of Aquastat settings a procedure to enter the adjustment mode is required To enter the adjustment mode press the UP DOWN and I buttons simultaneously for three seconds Press the I button until the feature requiring adjustment is displayed e HL High Limit e LL Low Limit Ldf Low Limit differential F C For C Then press the UP and or DOWN buttons to move the set point to the desired value After 60 seconds without any button inputs the control will automatically return to the READ mode To use the L7224U in a cold start boiler application disable the Low Limit function by pressing the UP arrow button DOWN arrow button and I buttons simultaneously for three seconds Then push the I button until LL is displayed Then press the down arrow button until OFF is displayed Display In the RUN mode the Aquastat will flash bt boiler temp followed by the temperature i e 220 followed by F or C To read boiler settings press the I key to read the paramete
3. LED is ON LL If yes replace control ZC LED is check for 120__ e If yes check zone OFFS ya oo ZC relays circulators an a Refer to Fig 5 for Display and LED locations b ZC LED ON indicates ZC terminal power is OFF c ZC LED OFF indicates ZC terminal power is ON Automation and Control Solutions Honeywell International Inc 1985 Douglas Drive North Golden Valley MN 55422 customer honeywell com U S Registered Trademark 2006 Honeywell International Inc 69 1957 1 Rev 06 06 and wiring Honeywell Limited Honeywell Limit e 35 Dynamic Drive Toronto Ontario M1V 4Z9 Printed in U S A on recycled paper containing at least 10 post consumer paper fibers Honeywell
4. oller Operating Sequence Action System Response Thermostat Circulator starts when water temperature is calls for heat above Low Limit setting if applicable Boiler temperature is checked Burner starts when water temperature is below High Limit setting Boiler exceeds the High Limit Burner is turned off Burner restarts when the water temperature drops below the High Limit setting minus the differential Thermostat is satisfied Circulator and burner turn off Error conditions If an error condition is detected all outputs except ZC are shut down Burner is off Control continues to function and restarts when error is corrected During the error check sequence the system checks for drift in the sensor and corrosion in the connections Error conditions If error condition 6 or 7 occurs the control has reset the High Limit Low Limit and Differential Setting to a default setting and will continue to run at those settings Performance of the system will be degraded Error condition 8 If the error condition is detected all outputs except ZC are shut down Burner is off Control continues to function and restarts when all three user keys have been pressed longer than 60 seconds Troubleshooting When attempting to diagnose system performance reference the LED display to help identify specific areas not working properly The LED display will scroll err followed by a digit 1 8
5. r of interest For example press I HL High Limit is displayed followed by a three digit number i e 220 followed by F or C L7224 SERIES Pressing the button again will display the LL Low Limit followed by a three digit number and the corresponding degree designator See the table below for an explanation of display readout After approximately 60 seconds without any key presses the display will enter a dim display mode To return to the bright display mode simply press and release any key Display Text Description Shows bt Boiler Temperature b k HL High Limit H L EL Low Limit Lk Hdf High Limit Differential Hd F Ldf Low Limit Differential L dF tt Local Thermostat Status E E tte Enviracom Thermostat Status E k E brn Burner Status brn cir Circulator Status i r ec Zc Zone Control L Zr Zone Request er err Error Code Err f i oF Degrees Fahrenheit or C Degrees Celsius L M22149 Table 1 LED Error Codes Error Code Cause Action Err1 Sensor fault check sensor Err2 ECOM fault check EnviraCOM wiring Err3 Hardware fault replace control Err4 B1 fault check B1 wiring voltage Err5 Low Line Check L1 L2 110 Vac Err6 Fuse Check ECOM wires Replace fuse Err7 EEPROM HL LL Hdf Ldf Reset to default values Err8 Repeated B1 fault voltage present at B1 when output is turned off check B1 wiring voltage 69 1957 1 2 L7224 SERIES Table 2 L7224 Contr
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