Lochinvar 90, 500 service manual Troubleshooting

Installation & Service Manual

9Troubleshooting

Troubleshooting Guide: 315,000 - 500,000 Btu/hr Models - Boilers 90,000 - 500,000 Btu/hr Water Heaters F9/M9

Step 1:	Is the spark
	ignitor sparking?
		Yes

Step 2:	Is the pilot
	staying on?

No

No

	Check continuity on the spark				Check for an open
	cable. Check for 24 VAC on				sensor. If no open
	the 24v terminal (gray wire)				sensor, make sure
	on the ignition module				there’s a call for
					heat. If call for heat
					is present, replace
					temperature control
Check the pilot				Yes
		No
tube for gas.
Check draft
			Replace ignition
			module			No

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

Step3:

Is the gas valve getting 24 VAC to the MV terminal?

Yes

No	Replace the
	ignition
	module

Check gas pressure and make sure gas valve knob is on.

Yes

No

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

Yes

No

Check voltage to and from the transformer.

No

Check incoming 120 VAC

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.

Check each of the following for an open:

-X and B on the terminal strip -purple and gray wires on the vent damper plug

-the two gray wires on the louver plug (315 and 360 models only) -V and P on the terminal strip

-auto reset high limit

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