Heater troubleshooting
October 2, 2010 6:32 PM   Subscribe

It's getting cold, and the heat in our newly-purchased but old house won't turn on. Can you help troubleshoot, or should we just call in a professional?

Our heat is gas-powered steam heat via a Peerless boiler. This is our first cold season in the new house. The heat worked during the inspection 4 months ago but obviously hasn't been used since then.

What we've done: not much. Turned thermostat to Heat and set temp a few degrees above current temperature in the house. Waited an hour and when it became clear the radiators weren't warming up, poked around the boiler. The pilot light is on, but beyond that I don't know what to check. The boiler is definitely not turning on - no flames besides the pilot, and the temp/pressure gauge on the side shows it's still cold.

Is there anything we can check without blowing our house up? Or is this call a professional territory? It's not *that* cold and our brick house is a good heat sink so we can make do with blankets and such for now.
posted by misskaz to Home & Garden (22 answers total)
If you have radiators, give them a good bleeding to make sure there's no air in the pipes. The spigots are usually near the ground where the pipes come out of the wall or floor.
That's something you'll generally need to do every year when it's time for the heat to come on.
posted by L'Estrange Fruit at 6:47 PM on October 2, 2010

Based on my very limited experience, I'd say you might want to take a look at the thermocouple. More information and troubleshooting pages here:

posted by ElDiabloConQueso at 6:48 PM on October 2, 2010

doh, on reread I see your boiler is cold. Sorry! That's something I'd generally call the boiler company about.
posted by L'Estrange Fruit at 7:00 PM on October 2, 2010 [1 favorite]

Doublecheck your thermostat. We had a similar problem, and it turned out that the thermostat display box took four batteries instead of what we thought was two (the layout was really odd). Once we replaced all four, the boiler woke up right away.
posted by vickyverky at 7:06 PM on October 2, 2010

does the boiler have a switch? Some do.
posted by parmanparman at 7:08 PM on October 2, 2010

yah, and crank the stat further up, too, more than just a couple of degrees, just to check, could be disparity between what's shown and what needs for the heater to be activated
posted by dancestoblue at 7:09 PM on October 2, 2010

Response by poster: We did later crank the thermostat to 75 (current house temp is 65) and still didn't get anything. And parmanparman, there is a switch and it is on.

The good (or telling?) news is that there was a brand new thermocouple left by the previous owners in a drawer. Replacing it looks fairly straightforward, so we're gonna try that. I'll be sure to update the thread if it works or not.

And to clarify, I said in the question steam heat but I guess it's actually hot water? Whatever, it's the kind with the big old (I think beautiful) radiators in every room.
posted by misskaz at 7:16 PM on October 2, 2010

Just to be clear, you turned the switch off for a couple of minutes then turned it back on right? Those are usually "reset" switches.
posted by saradarlin at 7:37 PM on October 2, 2010 [1 favorite]

Response by poster: There is a switch in a junction box between the boiler and the circuit beaker panel. Should we turn that off then on? I thought it was more of a switch that just interrupted power to the boiler, not a reset/ part of the boiler itself. But we can try it if it's worth a shot.
posted by misskaz at 7:42 PM on October 2, 2010

Response by poster: So far no change with the new thermocouple, by the way.
posted by misskaz at 7:46 PM on October 2, 2010

Radiators are hot water. Best kind of heat too, imo.
posted by L'Estrange Fruit at 7:49 PM on October 2, 2010 [1 favorite]

Radiators can be either steam or hot water.
How to Take Care of Your Home by Douglas Tuomey has illustrations and tips about how to bleed hot water radiators, and other troubleshooting tips.

Especially since you're new in the place, I think it would be a good idea to get someone to come out and check out the furnace and the pipes etc. They can clean the flues and be sure everything's safe and can answer any questions you might have.
posted by LobsterMitten at 8:08 PM on October 2, 2010

(I should say, I link that book just because it has nice illustrations and a charming writing style, but obviously it's out of date - so don't go wrapping your pipes with asbestos etc like it suggests.)
posted by LobsterMitten at 8:25 PM on October 2, 2010

(Sorry if this is ridiculously obvious but..) Have you tried calling the previous owners?
posted by addelburgh at 9:11 PM on October 2, 2010

Is there oil in your boiler? We had radiant heat (blissfully) in my house in DC. And the one night it got cold, no heat. Turns out there was no fuel to heat the water in the boiler. Felt like a total idiot getting the repair guy out at 3:00am when all we needed was a fuel oil delivery.
posted by crush-onastick at 10:02 PM on October 2, 2010

Besides the switch (which is an emergency or service cut-off) there is also a breaker or fuse in the main box. Check that.
If it is steam heat there will be a vial in the boiler that is used to check the water level. The boiler may be dry. ( another way to tell if it is steam is to look at the radiators. They will all have a release valve about 3/4 up on one side. )

After that I'd call a gas heat tech.
posted by Gungho at 5:39 AM on October 3, 2010

Response by poster: Calling the previous owners is out - they moved to California and we don't have their number.

It's not oil- fueled - it's natural gas and the gas is definitely on (as evidenced by the other gas appliances working and the pilot light working. I made sure the gas line to the boiler is open.)

Already checked the breaker. Looks like we need to call in a professional. I'd kind of like to bring someone in to explain the system to us and show us how to properly care for it anyway. Thanks everyone for the help!
posted by misskaz at 6:37 AM on October 3, 2010

For future reference, the pilot light wouldn't be lit if the thermocouple wasn't working - the thermocouple exists to make sure that the pilot light is still burning. (pilot light warms thermocouple, which sends electric charge to valve saying that gas is burning, keep it coming)

Does your boiler have a valve that looks anything like this?. What you are looking for specifically is a knob that says "On" "Off" and "Pilot".

I'd say that there's a good chance your valve has been switched to "Pilot" mode for the summer and just needs to be turned on (apologies if this is too obvious but occams razor etc.)

Follow the main gas line in until you find the valve and look for that knob!
posted by davey_darling at 7:59 AM on October 3, 2010

Response by poster: Thanks davey, but the knob was already set to "on". Plus we had to turn it off then on again to change the thermocouple. That's interesting about the pilot & thermocouple... During the inspection our inspector noted there was a box of matches on the boiler, indicating there were pilot light issues. When we moved in the matches were gone and there was a used thermocouple hanging from one of the pipes. I wonder if the sellers broke something when they replaced the thermocouple.

I might try to figure out if there's enough water in there. Online research shows the PSI should be 12-13 cold, but our gauge reads more like 10.
posted by misskaz at 8:44 AM on October 3, 2010

Does your boiler have any electronic controls or is it strictly mechanical? If you have a model number to post that might help with remote diagnostics like this.
posted by davey_darling at 9:27 AM on October 3, 2010

Call a professional. Boilers + steam + high pressure + oil ignitor + flame chamber + etc. = not on fix w/out experience list.
posted by buzzman at 11:49 AM on October 3, 2010

Response by poster: In case anyone was wondering - turns out when the electrician replaced the wiring in our basement and replaced the switch for the heater, he cranked the screws on the switch so hard that it cracked inside. The thing just wasn't getting any power. Easy fix once the boiler tech figured it out.
posted by misskaz at 5:39 PM on November 2, 2010

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