Unusual furnace behaviour (1 Viewer)

[John Watson]

It's an oil burning furnace that heats water that is pumped to several different zones of the house.

As of this morning, it has been making a steady low noise, as well as the regular (normal) much louder noise, when the burner starts and heats water from time to time.

Since there are often periods when there is no noise, I'm sure that the steady background noise is unusual.

I'm thinking this steady noise might be something to do with the pumping?

If it wasn't Saturday, I'd turn off the electrical breaker to the furnace, then restart it, to see what happens, but I don't want to lose the furnace during cold weather this weekend.

Any ideas?

 

[Gerald LaFrance]

Call a Professional !!

 

[Philip_G]

is the noise there before the blower motor starts, just after the burner lights? Could also be a blower motor going out.

 

[John Watson]

Philip, by blower, do you mean the roar when the furnace is "on"? The noise I'm thinking is unusual, is a constant low noise, which is occasionally over-ridden by the noise of the furnace working.

I turned the thermostat down (from about 75 to 65) in a part of the house which was overly warm about half an hour ago, and the rads in that area are still hot. I'm starting to think the thermostat may be gone, and is still calling for heat in that zone.

I don't want to call the furnace people on the weekend if it's a trivial problem.

Thanks for any suggestions.

 

[Cees Alons]

Could it be the water pump? Either standing still (you can probably give it a twist with a screwdriver) or running dry (check the water level / -pressure)?

Good luck.


Cees

 

[DaveNel]

It could be you need to add water or mebbe its losing its prime from time to time. Is it a hissing sound. I have worked on these before and water if not at the right level will cause weird sounds to happen. But as you said if the therms gone it could cause some probs and added noise.
Turn the temp all the way below 70 degrees and see if it still runs. if it shuts off then the therm isnt the prob. follow the thermostat cable and make sure it is ok.

 

[DaveNel]

Sorry I had that backwards (LOL) turn the temp up and if it shuts off the therms ok. Another thing I was thinking about
Rare but I have seen it in a couple is buildup clogging pipes and pressure building up. Then the clog breaks free then clogs again somewhere. Having that kind of system is kinna hard to know where problems are.

 

[Philip_G]

disregard, I was thinking it was a forced air furnace that also heated water.

 

[John Watson]

Thanks for all the ideas, guys.

The thing is still chugging along, so we'll ask for a service call from our fuel guys on Monday.

 

[John Watson]

Turns out it was not the thermostat, but was a little motor in a valve that controls the sending of hot water.

Apparently it can fail in the "on" position. Motor replaced. No harm done, just a little bit of fuel oil used unnecessarily, and the experience of living in a sauna for a few hours