Lochinvar 000 - 500 - Manual (Page 45)

45
TROUBLESHOOTING GUIDE
90,000 - 270,000 Btu/hr Models - Water Heaters F1
Is the pilot lit?
NO
Check for gas. Check the pilot
assembly and thermocouple.
Check the gas valve for proper
operation. Clean and replace.
Is the gas valve
getting 24VAC?
STEP 1:
STEP 2:
NO
Is there 24 VAC
(purple 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?
NO
Check for an open
sensor. If not open,
replace temperature
controller.
Unit is running.
STEP 3:
NO
YES
Check X and B on the
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.
Check 24VAC at R and W on
the (EMS) terminal strip.
Check the vent damper or
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.
NO
YES
YES