Furnace on the fritz

[peter eldergill]

Doesn't it always happen...furnace decides to act up as soon as the weather turns cold.

My wife woke me up at 6 AM this morning as the house was at 15 Celsius (52 F). Yikes that feels cold!

We've had technicians in to try to fix it and let's just say that we;re getting a new furnace on Tuesday (Our federal government will be supplying us with a rebate for updating to a high efficiency furnace). Unfortunately that doesn't help us right now.

Luckily it's shutting off sue to a poor signal somewhere so resetting the furnace sometimes gets it to turn on, so we can get heat.

I probably reset the furnace 40 times this morning before it finally turned back on. It took an hour. I ended up marking some papers while doing it.

Now I'm looking at the thermostat and I see that it appears to be not working again . Oh well, here we go again!

Pete

[closetgeek]

Same thing happened to my mother. First time she had to turn on her heat, it stopped working. Of course it was on a Sunday night too. Looks like you just have to sleep a little closer to your wife until Tues. Good luck.

[Fazor]

Lips are blue, my eyeballs frozen through.
Well don't you know, it's not an easy fix.
Furnace on the fritz!

[tashirosgt]

Efficient furnaces are complicated, so you may have a similar problem years hence. My Carrier 58ASXA100-JG is an efficient furnace of a generation ago. If it runs for more than about ten minutes, it shuts off and doesn't come back on. Like yours, the problem is fixed by resetting, i.e. turning the power on and off. I think the problem is due to the temperature sensor (internal to the furnace, not the house thermostat) falsely saying that the furnace is getting too hot. Fortunately, on a typical Winter day in southern NM, it only takes about 5 minutes for the furnace to bring the temperature up. If it is shut off by the thermostat, it never needs the resetting procedure.

[mugaliens]

Now I'm looking at the thermostat and I see that it appears to be not working again . Oh well, here we go again!

Pete

What? The thermostat, or the furnace? Thermostats are $25, and the most complex electronic thermostats for multistage heat pumps are less than $50.

Furnace efficiency won't save you as much as plugging all gaps and balancing your insulation.

[peter eldergill]

What? The thermostat, or the furnace? Thermostats are $25, and the most complex electronic thermostats for multistage heat pumps are less than $50.

Furnace efficiency won't save you as much as plugging all gaps and balancing your insulation.

It's definatley the furnace. We've had this problem before. I just noticed on the thermostat that the system was on according to the thermostat but nothing was happening from the furnace.

We've inuslated the house as much as we can without tearing the whole place down (a la Mike Holmes). This is more about reliability and peace of mind. Our furnace is old and almost time to replace. We also get a rebate from the gubmint as well.

Pete

[Donnie B.]

Funny you should start this thread just now. I went through a similar problem last week. One evening I noticed the house seemed cool, and the thermometer confirmed it (60F or so).

I don't have a fancy new furnace, just a little old gas-fired boiler for forced hot water. I figured the pilot had gone out, but it was normal. The thermocouple was putting out the normal .45 volts, too, and the thermostat was quite obviously in the command-heat state. When I shorted across the thermostat connection at the gas valve, it came on.

It seemed like the problem was in the killswitch, which is in series with the thermostat and is intended to shut off the gas when the water temperature in the boiler exceeds a preset limit. To check it I disconnected it and shorted the wires (bypassing it temporarily). Uh-oh... no good! I was starting to consider weird problems like a break in the thermostat wires. I decided to hook the killswitch back in the circuit, then troubleshoot the thermostat further. As soon as I reconnected the killswitch, the gas came on and it has worked fine ever since.

There are only two things I can imagine that could account for the repair. Either there was corrosion on the wires connecting to the killswitch that got scraped away in handling, or there was some other break in the thermostat wiring that cleared up as I messed around with it.

Either way, it's a lot nicer to have a warm house. But it may be time to think about replacing that boiler (it's about 45 years old) and getting a higher efficiency one. I've already tightened up the house considerably -- new attic insulation, some significant "hole plugging", and replacement windows with low-e glass. Next year may be the time for the furnace, considering the Federal subsidy and all.