Monday, February 22, 2010

Brrrrrr

Woke up late and wrapped in more blankets than usual, awakened by a Tam who was also in more layers than usual: the furnace seems to be no worky!

It may just be a wonky thermostat; it's an old-fashioned type, with actual physical contacts on a bimetallic element and it no longer goes "sproing" when adjusted back and forth past room ambient. On the other hand, the blower works; and with that, we're at the limit of what I'll do with a gas furnace when I can afford to hire an expert.

Called 'em, a local outfit I've used for years, and they're sending a tech out. 'til then -- brrr!

13 comments:

og said...

Jumper the contacts. if it goes on, it's the thermostat.
Is this a floor furnace? If so, they tended to have millivolt gas valves that generated their own electricity. If the thermopile is gone or failed it will have the same result- no clicky, no heaty. Here's a primer on the millivolt valves.

http://toolbox.invensyscontrols.com/spaw2/SiteContent/Files/FAQ/ControlTips-MillivoltSystems.pdf

Newbius said...

The Big Box home improvement stores sell t-stats, all the way from cheaply to ones that make coffee for you. Replacement is 4 wires and 30 minutes of time and they are simple compared to warp drives on star ships. If it doesn't solve the problem, you have at least upgraded an unreliable antique and can call a semi-pro about the rest. If it does solve the problem, you've saved yourself a $100 house call.

Nathan said...

Well, damn, I probably have two or three 'stats lying around from Dad's old stock that I could have given you.

Maybe next time.

Roberta X said...

I'm not a hundred percent sure it's the 'stat -- though that seems most likely. What I must do, is get to work. Can't let the house, cats. Tam freeze in the meantime, sooo....

'Druther fix it myself. But I don't get my 'druthers.

Jeffro said...

Don't forget to drip the faucets.

Roberta X said...

Og: I know whereof you speak. This puppy is a newer, pilotless type: no thermopile. It's got a start-up sequence like a big transmitter.

Last place I owned had a gravity-fed coalburner, converted to forced-air gas. There was an 18" ring-shaped burner in the old firebox with a pilot in the middle -- 'stat would tick over and you'd hear "hissssssssssssssssss......WHOMP!" as it lit. Only the hiss was like twenety seconds. Eeee!

Nathan said...

If the pilot light is not lit (assuming it's a standing pilot model) and refuses to remain lit after you let up on the safety button, it's probably the thermocouple. Although it could be the pilot light safety solenoid.

Since you mentioned the blower, I doubt you have a millivolt system -- normally you see those on old gas systems like floor furnaces (as Og mentions) or gravity feed furnaces that did not have 120v run to them (so they did not have 24v transformers for a low-voltage control system).

The last time I woke up to a problem like this, it turned out to be the pilot light safety solenoid on the gas valve -- the part the thermocouple screws into. Did I mention this happened in January 2009 on the coldest morning we'd had in years, i.e., -12F? Luckily I was able to get downtown in a hurry and buy a new gas valve from Dad's old supply house and had it installed in three shakes of a lamb's tail. It still took all day to warm the house back up...

Nathan said...

Whoops, missed the "no standing pilot" bit. So ignore me :)

Jim said...

>>"hissssssssssssssssss......WHOMP!" as it lit. Only the hiss was like twenety seconds. Eeee!<<

We are all poorer because we don't hear things like that any more. The floor furnace "whooommmp" in one of my boyhood homes was better than any security blanket. It stated with the utmost authority that in this house, at this time, human ingenuity had whomped cold cruel nature in straight falls.

Now we get invisible and silent digital creeps whose function and malfunction is as much a matter of voodoo as mechanics.

Stranger said...

For no flame, the most common problems the tech who drinks coffee with us says are the 24V transformer that powers the thermostat and gas relay, the heater element that gets red hot and ignites the gas on the pilotless ones, and the thermocouple that senses the pilot flame on the ones with pilot lights.

Mechanical thermostats are rarely a problem - but I am sure you are like I am, with a couple of suitcases full of jumpers.

Neither troubleshooting or replacement are beyond the capabilities of an average tinkerer, much less an electronics tech.

Provided the tech is equipped with an operating nose. Gas at least should be pungent enough to give you warning when you have a dangerous problem.

Stranger

og said...

Good call. At some point the tech requires qualified personnel; hobbyists can fix but the delay time is more than comfortable, in this weather.

Hope you're warmest soonest.

I seem to remember Roseholme being of an age that it might have once had gravity or floor heat, glad it's got a newer heater.

Turk Turon said...

Poor Slinky!

Get her a heating pad, stat!

reflectoscope said...

Fixed?

If it stays sucky you could hang out here, it is barely below freezing.

Jim