Honeywell AQUASTATIC L7224 user manual

Summary of the content on the page No. 1

69-1957-1.fm Page 1 Tuesday, June 20, 2006 11:06 AM
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®

Summary of the content on the page No. 2

69-1957-1.fm Page 2 Tuesday, June 20, 2006 11:06 AM L7224 SERIES Pressing the I 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 HL High Lim

Summary of the content on the page No. 3

69-1957-1.fm Page 3 Tuesday, June 20, 2006 11:06 AM L7224 SERIES Table 2. L7224 Controller 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 Burner is turned off. Burner restarts when the the High Limit. water temperature drops below the High Limit setting minus the different

Summary of the content on the page No. 4

69-1957-1.fm Page 4 Tuesday, June 20, 2006 11:06 AM a Table 3. Troubleshooting Guide . System Diagnostic Condition Condition Check Action Boiler is Display is ON; 120 Vac at B1- • If no, replace control. cold, TT-LED is ON B2 • 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- • 120 Vac at C1-C2, hot, house TT-LED is ON C2 check wiring to pump is cold C1 LED is ON • Wiring ok, is pump r