Low Water Cutoff (Lwco) - Standard C-More Test; Shutting Boiler Down For Extended Period - Watts AERCO Benchmark OMM-0121 Operation And Maintenance Manual

Benchmark 750-3000 Boiler Operation & Maintenance Manual
SECTION 4 – MAINTENANCE

4.9.2 Low Water Cutoff (LWCO) - Standard C-More Test

Perform the standard Low Water Cutoff test using the C-More Controller as described below.
Low Water Cutoff (LWCO) - Standard C-More Test Instructions
1. Turn the AC power to the unit to the ON position.
2. Press the TEST switch on the C-More Controller and confirm that the blinking LOW
WATER LEVEL message appears on the C-More display within 4 seconds.
3. Press the RESET key, followed by the Clear button, and confirm that the LOW WATER
LEVEL message is cleared.

4.10 SHUTTING BOILER DOWN FOR EXTENDED PERIOD

If the boiler is to be taken out of service for an extended period of time (one year or more), the
following instructions must be followed.
Shutting Boiler Down For An Extended Period Instructions
1. Set ON/OFF switch on the C-More Controller to the OFF position to shut down the boiler's
operating controls.
2. Disconnect AC power from the unit.
3. Close the water supply and return valves to isolate boiler.
4. Close external gas supply valve.
5. Open relief valve to vent water pressure.
6. Open the drain valve and drain all water from the unit.
7. If the temperature in the storage location can ever get below freezing, for even a short
time, you must drain all water from the unit before the temperature falls below freezing.
Step 6 is not sufficient, as it leaves some water in the bottom of the heat exchanger
chamber. You must then use a suction pump inserted through the inspection ports to
remove all water from the bottoms of the heat exchanger chamber and base assembly.
WARNING!
If the temperature will ever fall below freezing, failure to drain all water can cause heat
exchanger tubes to crack and fail.
OMM-0122_D • GF-206 • 5/9/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 57 of 164