Form #43219000
Jan 2014
14.4)
TRANSFORMER
The transformer is not serviceable
Check that the transformer is receiving 230VAC power supply. Blue and brown wires
Check that there is 24VAC on the outlet side of the transformer. Red and yellow wires
Replace if necessary.
14.5)
HIGH TEMPERATURE LIMIT SWITCH
The high temperature limit switch is not serviceable.
The high temperature limit switch is wired in series with the gas valve. It serves the purpose to prevent the heater
from overheating. In normal operation the switch is normally closed. If the high temperature limit switch has been
activated it must be manually reset by pushing the red reset button in the center. The heater must be allowed to
cool down for at least 15 minutes. Turn off power to heater before pushing the reset button. When reset successful
a click is heard.
Remove wires and place an ohm meter over the switch terminals and check that there is continuity after the red
reset button has been pressed.
Annual test – be careful the switch will be hot in some areas.
To test the operation of the high temperature limit switch remove it and hold a small flame to the vicinity of the
sensing portion of the switch. A “click” will indicate that the switch has activated. Place an ohm meter over the
switch terminals and check that there is NO continuity. Wait for the switch to cool and push the red reset button.
Place an ohm meter over the switch terminals and check that there is continuity.
Replace if necessary.
14.6)
FLAME SENSOR
The flame sensor is not serviceable.
The flame sensor transmits a millivolt signal to the ignition module indicating the presence of a flame. The flame
mV can be measured by disconnecting the purple flame sensing wire and placing a volt meter in series between
the purple and yellow wire. A voltage greater than 1mVdc (direct current) indicates a strong flame signal.
Inspect the ceramic portion of the flame sensor for any cracks.
Check the flame sensor rod for oxidation. Use steel wool to remove oxidation.
Replace if necessary.
14.7)
SPARK ELECTRODE
Both the spark electrode and hot surface igniter are not serviceable.
The spark electrode creates a spark across the 2 rods which ignites the burner. The spark gap must be 3/16”
(0.188 inches or 4.7mm). Remove the spark electrode and carefully adjust the spark gap.
The ignition cable is an integral part of the spark electrode and cannot be removed.
Inspect the ceramic portion of the spark electrode any cracks.
Check the spark electrode rod for oxidation. Use steel wool to remove oxidation.
Replace if necessary.