25
EN
Water Heater Diagnostic Procedures
Component Diagnostic Question Action Based On Status Page
Orifice
Does the gas solenoid valve open when
there is a spark, but there is no ignition?
Does the burner fail to ignite, have an
erratic burner flame, or is sooting?
Check the orifice for blockages. 49
If blockages are present, clean the orifice. 36
P/T Relief Valve
Is there excessive weeping coming from
the pressure/temperature (P/T) relief
valve?
Confirm the weeping is excessive. Some
weeping or dripping occurs as the water
heats.
50
If the weeping is confirmed as excessive, the
P/T relief valve may have been dry-fired or is
defective. Replace the P/T relief valve.
40
Re-establish the thermal expansion air pocket. 39
Pilot Assembly (Pilot Models)
Does the pilot light fail to stay lit? Perform the following checks:
Confirm operation. Hold down the button for
at least 30 seconds when lighting the pilot.
N/A
Check the flame. The flame should be blue,
0.25 in. tall, and surround the thermocouple.
A weak pilot flame can be caused by low gas
pressure or a partially blocked pilot orifice or
pilot gas line.
Does the pilot fail to light? Perform the following checks:
Confirm the gas pressure is not too low or
absent.
29
Remove the pilot gas line to confirm gas is
present from the gas valve when in the pilot
position.
• If gas is present, there is a blockage in
the pilot gas line or pilot orifice. Clear the
blockage.
N/A
• If no gas is present, confirm that gas is
coming into the gas valve. If there is gas
in the gas valve, the gas valve is defective.
Replace the gas valve.
35
Pressure Switch (On Demand Models)
When the water and the fan are running,
does the appliance fail to attempt
ignition?
Check for continuity across the two terminals
on the pressure switch when the fan is
running.
43
If there is no continuity, check that the straw,
hose, and inlet/outlet nipples are free from
debris. If a blockage is found, clean the straw,
hose, and inlet/outlet nipples.
49
Confirm that the Water Heater fires when
the two wires connected to the switch are
jumped.
42
If the burner does not fire, confirm the voltage
to the motor is at least 10.5 VDC. If so, the
pressure switch is defective. Replace the
pressure switch.
43
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