Lochinvar 000 - 500 - Manual (Page 62)

9
Troubleshooting
62
Installation & Service Manual
Step 1:
Step 2:
Step 3:
Is the pilot lit?
Yes
Is the gas valve
getting 24VAC to
the MV terminal?
Yes
Check gas pressure
and make sure the gas
valve knob is on
No Check gas pressure.
Check the pilot assembly
and thermocouple. Clean
the thermocouple and
pilot or replace.
No Is there 24 VAC (purple
wire) on the 4-pin
connector plug on the
temperature controller?
Yes
Is there 24 VAC (tan
wire) on the 4-pin
connector plug on
the temperature
controller?
Check for an open
sensor. If no open
sensor, make sure
there’s a call for
heat. If call for heat
is present, replace
temperature control
No
Yes
Check each of the
following for an open:
- X and B on the
terminal strip
-purple and gray wires
on the vent damper
plug
-V and P on the
terminal strip
-auto reset high limit
No
Check 24 VAC at R and W on
the terminal strip.
Check each of the
following for an open:
-white and purple wire on
the LWCO plug
-rollout switch
-manual reset high limit
-spill switch
If any of these devices are
open, press the reset
button.
Yes
No
Check
voltage to
and from the
transformer.
No
Check incoming
120 VAC
Troubleshooting Guide:
90,000 - 270,000 Btu/hr Models - Water Heaters F1