Everything was fine, but now house temperature not reaching thermostat setting.....

joe8612

Hi,
I have a gas single pipe steam system in my house and everything has been fine for the 10 years that I've been here. But the last week or so, when the heat kicks on, it doesn't get up to the thermostat setting - tends to get within 3 degrees. And when I crank up the thermostat to maximum setting, it doesn't kick on again even if I wait. There is plenty of water in there and no light on the water shutoff. My thinking is that maybe something wrong with the Thermostat or the pressure cutoff? Thermostat is programmable one and has been fine for about 6 years. Pressure setting in basement has never been touched - set to 0.5. The Got 2 of Dan's books but didn't find a clear path here..... Any suggestions would be appreciated.
Joe

nicholas bonham-carter

Does the thermostat need new batteries?
If new batteries do not correct the problem, then use a jumper wire with alligator clips to short out the contacts which control the burner. If the boiler fires, then the problem would appear to be in the thermostat. The Honeywell Visionpro is popular here, set to 1 CPH for steam.--NBC

Fred

Something is shutting that boiler off and not letting it re-fire. You may need to have a service tech look at it. It could be the thermopile or a flame sensor or a flue gas sensor, maybe even the flue damper isn't opening (if you have a flue damper). It needs to be checked by someone who has the proper equipment to test the sensors.

nicholas bonham-carter

You can remove the cover of the pressuretrol, and activate the rocker arm (with a non-conductive pencil), on the bottom to force the switch to close. This test will tell you if the pressuretrol is at fault.--NBC

joe8612

Thanks very much for your suggestions everyone. I am going to give them a try and will post back the results.
Joe

joe8612

Sorry, I never wrote back about what the problem was - it turned out to be a problem with the low water cut off. Replacing that fixed the problem.

nicholas bonham-carter

Thanks for the update!--NBC