Plumbing in the Home/water heater pilot light


QUESTION: my friend has a reliance model#640gort 300.the pilot light went out and we cant get it to re light.have tested thermopile and the other sensor on the acess panel.both test good.was told control panel was bad.took access panel with burner out heated thermopile control panel light activated with no codes.pilot will light only with panel light on but will not after thermopile cools a new control panel but dropped it coming out of store.would this destory the new control panel because no change with new controlpanel installed.any help would be greatly apperciated

ANSWER: Charles, The number one cause of issues such as yours is a weak flame. The thermocouple must be hot and glowing red. Sometimes they get weak and need to be replaced. The Reliance 640 GORT uses a thermocouple not a power-pile. Two completely different things with each having unique problems. Clean the pilot assembly orifice and replace the thermocouple and you should be good to go. Here's how.


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QUESTION: thank you for the quick reply.this unit has the thermopile and is the sealed system.tested thermopile went to over 500 millivoltspretty fast.there is no gas suppy to pilot light when pushing button.only when control panel light comes on after warming thermopile with lighter.something is causing gas valve to be closed.iam sorry i didnt give more info on first question.the arrestor plate was very clean you think i hurt the control panel when i dropped it? thanks again char;es

Charles, My research on the 640 GORT shows a thermocoupling set up. Yours must be  a variation of sorts. Give the board a close look with a magnifying glass an check for hairline cracks. if it was still packaged it should be ok. I more heat is required on the thermopile then I would replace it as well  

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Jay Nicholas


Plumbing & Heating (warm air, hot water & steam heat)


40 years in the business, 40 years as a lic. master plumber in NY State. Retired

Graduated Magna cum laude at the School of Hard Knocks

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Commercial, residential and light industrial. You name it ...I have probably worked on it

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