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L7224 Series Oil Electronic
Aquastat
(2012 Compliant)
TECHNICIAN'S QUICK REFERENCE GUIDE
The following service procedure provides a quick overview
for L7224 Series Controllers. For more information, refer to
forms 69-1720 L7224U Installation Instructions, 66-1202
Wireless Outdoor Reset Installation Instructions, 69-2335
Outdoor Reset Installation Instructions, and 69-2343
Domestic Hot Water Module Installation Instructions. This
control is compatible with both wireless and wired
AquaReset Outdoor Reset Controls.
2012 DOE Compliance and Operation
Operation of this control may delay the burner operation
while the residual heat is circulated out of the boiler.
NOTE:
This operation may be different than earlier
electronic Aquastat
implement thermal purge.
On the L7224U settings can be adjusted to best fit the
requirements of the application.
Additional settings options are available to define an
outdoor reset curve for those systems requiring Outdoor
Temperature Reset and other adjustable parameters.
IMPORTANT
Outdoor Temperature Reset should be limited to
those systems consisting of a cold start boiler
and may include an indirect tank for domestic hot
water.
Outdoor Temperature Reset should not be used
with tankless coil systems as the low limit
setting required in such systems may limit
®
Controller
®
revisions which did not
69-1957-03
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Summary of Contents for resideo Aquastat L7224 Series
- Page 1 L7224 Series Oil Electronic ® Aquastat Controller (2012 Compliant) TECHNICIAN’S QUICK REFERENCE GUIDE The following service procedure provides a quick overview for L7224 Series Controllers. For more information, refer to forms 69-1720 L7224U Installation Instructions, 66-1202 Wireless Outdoor Reset Installation Instructions, 69-2335 Outdoor Reset Installation Instructions, and 69-2343 Domestic Hot Water Module Installation Instructions.
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Page 2: Adjusting Settings
® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER effectiveness and thereby projected increased efficiency of Outdoor Reset. 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. - Page 3 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER * Settings available for adjustment on the 3-digit display only if the AquaReset Outdoor Reset Module is installed. **Settings available for adjustment only when the W8735S1000 AquaReset Outdoor Reset Kit is NOT installed. Then press the UP and/or DOWN buttons to move the setting to the desired value.
- Page 4 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER Table 1. Display readout definitions. Text Description Display Error Code (if one is present) Boiler Temperature High Limit High limit differential Low Limit set-point (L7224 only) Low Limit differential (L7224 only) Local Thermostat Status EnviraCOM Thermostat Status B1 (Burner) output (ON or OFF) C1 (Circulator) output (ON or OFF)
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Page 5: Outdoor Reset
® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER Table 1. Display readout definitions. (Continued) Text Description Display Boiler Temperature Low Boost Period Boost Step Warm Weather Shutdown Temperature Display shows local setting; not the setting as modified by an external enviracom control. Settings are viewable only if the outdoor reset module and outdoor temperature sensor are installed and functioning properly. - Page 6 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER CAUTION Possible Equipment Damage When enabling the Outdoor Reset function, be sure to refer to the boiler OEM’s instructions for the lowest return water setting to avoid condensation in the heat exchanger, which can result in equipment damage.
- Page 7 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER Table 3. Boost Settings and Defaults. Minimum Maximum Parameter Name Value Value Default Boost period 5 minutes 30 minutes 10 minutes (or Off) Boost step 5 °F 20 °F 10 °F (or Off) BOILER TEMPERATURE HIGH LIMIT...
- Page 8 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER Table 4. LED Error Codes. Aquastat Error EnviraCOM Code Cause/Action Alarm Err1 Aquastat sensor fault; check water sensor. 18 Err2 ECOM fault; check EnviraCOM™ wiring. Err3 Excessive electrical noise or frequency out 18, 58 of range.
- Page 9 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER Warnings are generated to enunciate the system is not operating ® optimally, but the Aquastat is still operating and maintaining boiler temperature. In the instance where an Outdoor Reset Mod- ule is used, the warnings may indicate a reset curve setting error ®...
- Page 10 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER Table 5. L7224 Controller Operating Sequence. Action System Response Thermostat Circulator starts when water temperature is above calls for heat. Low Limit setting (if applicable) or above the Thermal Purge Temperature Limit (tPL) if Thermal Purge is enabled.
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Page 11: Troubleshooting
® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER Action System Response Error If an error condition is detected, all outputs except conditions ZC are shut down. Burner is off. The controller 1-5. 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. - Page 12 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER Table 6. Troubleshooting Guide. System Diagnostic Condition Condition Check Action Boiler is Display is 120 Vac system Turn system power on. cold, OFF. power. house is Display is 24 Vac T-T. No 24 V; replace cold.
- Page 13 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER System Diagnostic Condition Condition Check Action Boiler is Display is 120 Vac at C1- 120 Vac at C1-C2, hot, check wiring to pump. house is TT-LED is Wiring ok, is pump cold. running? If not, C1 LED is replace the pump.
- Page 14 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER System Diagnostic Condition Condition Check Action Boiler is Display is Boiler Demand 24 Vac on T-T (or hot, no signal from the 0 Vac on ZR-L2), water heater check wiring to water potable (either 120 Vac at heater water...
- Page 15 ® L7224 SERIES OIL ELECTRONIC AQUASTAT CONTROLLER 69-1957—03...
- Page 16 Resideo Technologies, Inc. 1985 Douglas Drive North, Golden Valley, MN 55422 1-800-468-1502 www.resideo.com 69-1957—03 M.S. Rev. 10-20 | Printed in United States © 2020 Resideo Technologies, Inc. All rights reserved. This product is manufactured by Resideo Technologies, Inc. and its affiliates.
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