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Water Heater Operation Checking the Draft
Figure 29 below shows the water heater's sequence of operation
when a call for heat is initiated. The ignition control module wilt
attempt to light the burner three times. If the ignition control does
not detect ignition it wilt enter lockout mode, indicated by display
flashing status code (see status code 3 page 38 and/or status
code 8 page 39).
Burn Hazard
Do not touch vent.
Doing so can result in burns.
SEQUENCE OF OPERATION
I as valve/thermostat will do a I
relay check (relay clicks will be
heard).
J.
I Display will show temperatureset point during call for heat. I
1
I raft Blower is energized.
4.
I
I ystem will verify pressure I
switch operation and start a
5 second pre-purge, then air
intake fan will turn off.
1
I gnitor will start a 12 second I
warm up period. "IGN" will
I
show on display.
I
I
I as valve/thermostat will open I
for 4 second trial for ignition
and fan will turn on.
1
I 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.
1
I as valve/thermostat is de- I
energized and air intake fan
continues for a post purge time
of approximately 5 seconds.
.I.
I ater heater returns to standby I
mode.
FIGURE 29.
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
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.
Flue Products Vented
to Ouside of Building
Dilution Air
Hood _
O'a"
Dilution Air L.
(Relief Opening)
,_ilution Air
_ Match
Air is drawn in for
combustion. Keep
area clean and free
from combustibles
and flammable vapors.
"6" Maximum
Air Gap
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.
Ifthe flame flutters or is blown out, combustion products are escaping
from the relief opening. Ifthis occurs, do not operate the water heater
until proper adjustments or repairs are made to the vent pipe system
and/or air supply requirements.
26