Installation & Service Manual

9Troubleshooting

Troubleshooting Guide:

90,000 - 270,000 Btu/hr Models - Water Heaters F1

Step 1:

Is the pilot lit?

 

 

 

 

 

No

 

Check gas pressure.

 

 

 

 

 

 

 

Check the pilot assembly

 

 

 

 

 

 

 

and thermocouple. Clean

 

 

 

 

 

 

 

the thermocouple and

 

 

Yes

 

 

 

 

 

 

 

 

 

pilot or replace.

 

 

 

 

 

 

 

 

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

Step 2:

Step 3:

62

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 voltage to and from the transformer.

No

Check incoming 120 VAC

No

 

Is there 24 VAC (purple

 

 

wire) on the 4-pin

 

 

connector plug on the

 

 

temperature controller?

 

 

 

 

 

 

 

 

 

 

 

 

 

Yes

 

No

Check 24 VAC at R and W on the terminal strip.

Yes

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.

No

Is there 24 VAC (tan wire) on the 4-pin connector plug on the temperature controller?

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

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Image 62
Lochinvar 500, 90 service manual Pilot or replace