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Discussion Starter #1
Greetings...long time lurker, first time poster. :)

I have (as mentioned in the subject line) a Tempstar DC90 furnace...and it has an "issue." When producing heat, the "smart" gas valve has an intermittent (but frequent) clicking problem.

Using the gas shutoff valve, I can marginally increase the gas flow to the smart valve, and the clicking will stop...but eventually, the flame rollout switch will engage, resulting in loss of flame.

By the same token, a very small change of inlet flow will allow the furnace to produce heat day in and day out...but the gas valve will return to it's pattern of clicking. Thoughts? Suggestions?

My thanks for your kind consideration.

:)
 

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If the flame rollout switch engages then you have a VERY SERIOUS problem and should stop doing what you are doing NOW or you will get a serious flashback and burnt wiring and possible fire from manually throttling the gas valve. Only time the rollout trips is if the heat exchanger is cracked or plugged up or the gas valve is overfiring. All these need to be checked by a Pro. The valve is clicking because you are reducing the inlet pressure and it CANNOT regulate properly. If there is a fire and the fire inspector will find out what you have being doing from the valve position then your insurance company is going to have serious issues with you.
 

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Discussion Starter #3
Thanks, Yuri. As I'm going to be out of town for about a month (and not desiring to strand my wife and children without heat), I'm going to schedule a service call from a local HVAC company.
 

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I hate to be overly dramatic but what you are doing is extremely dangerous and for all the other thousands of readers of these posts we cannot have other people making the same mistake.
 

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Discussion Starter #5
No worries about the drama...I asked, because I didn't know...and you gave me the info I needed...and again, thank you.
 

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Greetings...long time lurker, first time poster. :)

I have (as mentioned in the subject line) a Tempstar DC90 furnace...and it has an "issue." When producing heat, the "smart" gas valve has an intermittent (but frequent) clicking problem.

Using the gas shutoff valve, I can marginally increase the gas flow to the smart valve, and the clicking will stop...but eventually, the flame rollout switch will engage, resulting in loss of flame.

By the same token, a very small change of inlet flow will allow the furnace to produce heat day in and day out...but the gas valve will return to it's pattern of clicking. Thoughts? Suggestions?

My thanks for your kind consideration.

:)
you may want to check the little port view window on this furnace....fixed tons of them...when operating the little window is making a clicking noise just touch it ..it will stop...ben sr
 

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One of my wholesalers told me a bunch of those furnaces and valves were overfired as the installers did not check the gas pressure at startup and lots of heat exchangers got overfired and damaged. Running 4" WC. I had one split real bad where the flames enter the exchanger from overfiring.
 

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Discussion Starter #8
Called in the Pro...cracked heat exchanger. The unit is nearing the end of its lifespan, anyway, so we're just going to replace the whole shebang.

Thanks again.
 
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