Water Heater Operation
Figure 17 below shows the water heater’s sequence of operation when a call for heat is initiated. The ignition control module will attempt to light the burner three times. If the ignition control does not detect ignition it will enter lockout mode, indicated by display flashing status code
(see status code 3 page 30 and/or status code 9 page 31).
Checking the Draft
WARNING
Burn Hazard
Do not touch vent.
Doing so can result in burns.
Sequence of Operation
CALL FOR
HEAT INDICATED
BY FLASHING OF
DISPLAY SCREEN
STATUS CODES
CONTROL CHECKS TO ENSURE PRESSURE SWITCH IS OPEN
DRAFT BLOWER IS ENERGIZED
CONTROL CHECKS TO ENSURE PRESSURE SWITCH IS CLOSED, INDICATING BLOWER OPERATING AND THERE ARE NO VENTING BLOCKAGES (INLET OR OUTLET)
CONTROL ENERGIZES HOT SURFACE IGNITER (HSI)
MAIN VALVE ENERGIZES ALLOW- ING THE BURNER TO BE LIT BY HSI, DRAFT BLOWER ENERGIZES
FLAME SENSE ROD DETECTS FLAME OF MAIN BURNER
WATER IN TANK IS HEATED BY MAIN BURNER AND TEMPERATURE REACHES THERMOSTAT SETTING
MAIN VALVE
MAIN VALVE
HEATER RETURNS TO
STANDBY MODE
After successfully lighting the water heater, allow the unit to operate for 15 minutes and check the draft hood relief opening for proper draft (Figure 18). Make sure all other appliances in the area are operating and all doors are closed when performing the draft test. Pass a match flame around the relief opening of the draft hood. A steady flame drawn into the opening indicates proper draft.
DRAFT HOOD
RELIEF
FIGURE 17.
OPENING
MATCH
FIGURE 18.
If the flame flutters or is blown out, combustion products are escaping from the relief opening. If this occurs, do not operate the water heater until proper adjustments or repairs are made to the vent pipe system and/or air supply requirements.
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