Lochinvar 000 - 500 User Manual
44
Is the spark
igniter sparking?
igniter sparking?
NO
Check continuity of the spark
cable. Check for 24VAC on
the TH terminal (gray wire) on
the ignition module.
cable. Check for 24VAC on
the TH terminal (gray wire) on
the ignition module.
Is the pilot
staying ON?
staying ON?
STEP 1:
STEP 2:
Check the pilot
tube for gas.
Check for draft.
tube for gas.
Check for draft.
NO
NO
YES
Replace ignition
module.
module.
Is there 24 VAC (purple
wire) on the 4-pin
connector plug on the
temperature controller?
wire) on the 4-pin
connector plug on the
temperature controller?
YES
Is there 24VAC
(tan wire) on the
4-pin connector
plug on the
temperature
controller?
(tan wire) on the
4-pin connector
plug on the
temperature
controller?
NO
Check for an open
sensor. If not open,
replace temperature
controller.
sensor. If not open,
replace temperature
controller.
Is the gas valve
getting 24VAC?
getting 24VAC?
STEP 3:
Replace ignition
module.
module.
NO
YES
Check X and B on the
terminal strip if the flow
switch is installed. Check
for an open auto reset high
limit.
terminal strip if the flow
switch is installed. Check
for an open auto reset high
limit.
Check vent damper, 3-pin
louver relay connectors, and
venter proving.
louver relay connectors, and
venter proving.
Check 24VAC at R and W on
the (EMS) terminal strip.
the (EMS) terminal strip.
NO
Check the vent damper or
the vent damper plug and
the voltage to and from the
transformer.
the vent damper plug and
the voltage to and from the
transformer.
YES
Check all safety limit devices.
Check 4-pin low water cutoff
connector.
connector.
YES
YES
NO
TROUBLESHOOTING GUIDE
45,000 - 500,000 Btu/hr Models - Boilers & Water Heaters F9/M9