# steam boiler keeps running.



## vinpadalino (Aug 27, 2010)

I see between 2 to 3 steam boilers a year not common in my area. HO called she said the boiler runs all the time even when the tstat is off. The only way to shut the boiler off is emergency switch. Need some ideas, going out there tomorrow. Thanks.


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## vinpadalino (Aug 27, 2010)

Sorry Oil unit, and has a zone of baseboard heat on it.


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## Plumbworker (Oct 23, 2008)

First check the thermostat... Then Check to see if someone was fooling and jumped the tt's.. If not then check the thermostat relay make sure its not stuck or fused closed... 

those are most likely the first things i would check..

But im not that familiar with oil fired units


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## trick1 (Sep 18, 2008)

Basically, the thermostat, pressuretrol/vaporstat and the burner are wired in series and most likely tie into the T-T connections on the oil primary.


There are a few viable options....

1) the thermostat is stuck closed

2) There is a malfunction in the oil primary control.

3) A short occured somewhere in the thermostat circuit

I'd start by disconnecting the T-T terminals on the primary and see if that stops the boiler. If it does, then you know that there's an issue or a short in the thermostat circuit.

If the boiler continues to run, then there's an issue in the switching portion of the oil primary and it should be replaced, especially if it's a microprocessor type, (Honeywell R7148, etc..)

We've seen some real crazy and almost unexplainable lockouts due to issues with the microprocessors in some of these controls.

I've also seen wires pinched and actually staples put through thermostat cable from insulation contractors, etc....


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## vinpadalino (Aug 27, 2010)

Thanks guys. I will check all that out and tell you how it turns out.


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## vinpadalino (Aug 27, 2010)

I found a strap on aqustat set to 100. I re-wired some contol wiring and it's working great. Thanks all.


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