PILOT LIGHT TROUBLESHOOTING FLOWCHART
Does pilot light go out
when button is released?
Has the thermal switch
Check for insufficient
Are there openings
for make-up air to
enter the room?
Are the openings of sufficient size?
See Combustion Air Supply and Ventilation
section in this manual for requirements.
Is there a furnace/air
handler in the same room
as the water heater?
Does the return air duct for the furnace/air handler
draw its air from a separate location than the water
heater? See the Location Requirements section
and the Combustion Air Supply section.
Is there proper drafting at the
drafthood? See Checking the
Draft section in this manual.
Is the flame-trap free from
debris due to excessive lint,
dirt, dust or oil?
Check the water heater for a Flammable Vapor (FV) event. Note: it may
be necessary to remove the manifold door assembly to visually inspect
the water heater. Reference the Maintenance of your Water Heater
section of this manual for removal instructions.
Is the igniter wire insulation burnt or
show signs of discoloration?
Check Draft. (See Checking the
Draft section of this manual.)
Are the wires from the gas
control valve/thermostat firmly
connected to the switch?
Are the wires damaged
Replace the gas control
Install correct size make-up air openings
per the Combustion Air Supply and
Ventilation section in this manual.
Correct size of openings
to allow sufficient air.
Check the vent system for restrictions/obstructions and check
the vent termination height. Refer to the Installation Instructions
section of this manual for specific requirements.
Refer to the Use & Care Guide section of this manual for
information on cleaning the flame-trap.
Is the pilot tube
Shut-off the gas supply to the water
heater at the manual gas shut-off
valve, then contact Customer Service
and attempt a relight.
Is the thermocouple
Tighten the connection
Does the thermocouple pass the test?
Contact a local Heating, Ventilation, Air-
Conditioning & Refrigeration authorized
Does the flame-
trap show signs
Test the thermocouple using the following
procedure: Disconnect the thermocouple
from the gas control valve/thermostat. Using
a multimeter with alligator clip leads, attach
the red lead to the body (copper part) of
the thermocouple. Attach the black lead to
the end (silver part) of the thermocouple
that connects to the gas control valve/
thermostat. Follow the instruction to light
the pilot and watch the voltage readings on
the multimeter. After 45 seconds the meter
should read 12 millivolts DC or more.
Replace the thermocouple.
U N I T R O L
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