Water Heater Operation
Figure 29 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 38 and/or status code 8 page 39).
Checking the Draft
WARNING
Burn Hazard
Do not touch vent.
Doing so can result in burns.
SEQUENCE OF OPERATION
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 30). Make sure all other appliances in the area are operating and all doors/windows are closed when
Call for heat indicated by flashing of display screen status codes.
Gas valve/thermostat will open for 4 second trial for ignition and fan will turn on.
performing the draft test. Pass a match flame or smoke around the relief opening of the draft hood. A steady flame or smoke drawn into the opening indicates proper draft.
Gas valve/thermostat will do a relay check (relay clicks will be heard).
Display will show temperature set point during call for heat.
Draft Blower is energized.
System will verify pressure switch operation and start a 5 second
Ignitor will start a 12 second warm up period. “IGN” will show on display.
Main burner flame is detected by flame sense rod. Air intake fan and main burner will continue to operate until water temperature inside the tank reaches temperature set point.
Gas valve/thermostat is de- energized and air intake fan continues for a post purge time of approximately 5 seconds.
Water heater returns to standby mode.
Flue Products Vented to Ouside of Building
Dilution Air
Draft Hood 
Dilution Air
(Relief Opening)
Dilution Air
Match
Air is drawn in for combustion. Keep area clean and free from combustibles and flammable vapors.
FIGURE 29.
6” Maximum
Air Gap
Floor Drain
Outer Door
The water heater must be installed according to all local and state codes or in the adsence of local and state codes, the “National Fuel Code”’ ANSI Z223.1(NFPA 54)- current edition.
FIGURE 30.
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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