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Furnace troubles! UPDATE: Flame sensor? Hah. $640 please! Merry Xmas!
Figgy
Fighter of the night manChampion of the sunRegistered User regular
Fighter of the night manChampion of the sunRegistered User regular
So, I came home from work tonight around 10pm to a fairly cold house (66 degrees). The thermostat is set to 71. The little flame icon was on my thermostat, meaning the furnace is on; however, the furnace isn't actually on.
If I go and flip the furnace breaker (or the furnace light switch thing) off then on, the furnace kicks in a second later. Once it heats up the house and switches back on, it won't seem to come on till I flip the switch again.
Any ideas? This same thing happened last winter once, but it was an isolated incident and never happened again. Whatever the problem is, can I fix it myself somehow?
If I go and flip the furnace breaker (or the furnace light switch thing) off then on, the furnace kicks in a second later. Once it heats up the house and switches back on, it won't seem to come on till I flip the switch again.
Any ideas? This same thing happened last winter once, but it was an isolated incident and never happened again. Whatever the problem is, can I fix it myself somehow?
Figgy on
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Do you own your own place, or do you have a landlord?
I own. The furnace is as old as the house, just over 10 years. We bought the house a year and a half ago.
Would it make sense to just replace the thermostat myself and if that doesn't fix it, call a repair guy? It makes sense that the thermostat would be faulty, since it doesn't seem to be telling the furnace to turn back on.
When I flip the furnace switch off and on, it kicks in within 3 seconds without fail.
Flame sensor. Happens to me.
There's a wire that senses whether there's fire or not, right in the line of the jets. It's busted, and not sensing the heat. So to keep you from getting gassed to death (it thinks) it stops the furnace from working. It won't try again for 3 hours (depending on model). When you kill the power, it resets the timer and gives it another go.
You've got 2 choices. The safe one is to clean the sensor. Some steel wool is all you need, but that's not the problem. I can't get to mine because I can't remove a certian bolt, so I had to call a dude. it took him 10 minutes and I told him what to do, but it still cost me like $100 bucks. The other time, I just cycled it on and off over and over trying to figure out what was wrong. Enough runs apparently fixed it, because it worked for another year before it sent out again.
I'd suggest calling and asking the specific question as to what they will charge you to clean the flame sensor. I can't tell you that you should just do the cycle thing, but it just happened to work for me after LOTS of fire.
Can you link me to a picture as to what the flame sensor will look like? I'm handy enough that I'm not afraid to clean it, as long as I'm not messing around with gas lines or anything like that. Should I not even bother with replacing the thermostat?
Other than that, if it's a matter of paying a guy $100 to come and fix this, I find that to be well worth it for the peace of mind.
if you look at your furnace burners there will be a little metal rod sticking down in front of one of them with a wire coming out of the top, this is the thermocouple (flame sensor) you can simply undo the bolt that holds it in, take it out, and than just rub it with some steel wool or sand paper to get the carbon buildup off of it. just make sure you turn off your furnace before doing this. should take all of 5mins to clean it up and a lot cheaper/easier than replacing a thermostat so try it first to see if it solves your problem
Edit: Erm, here is what I'm seeing with the cover off.
Full: http://img818.imageshack.us/img818/1488/75589192.jpg
Detail: http://img811.imageshack.us/img811/2856/76489975.jpg
Do I need to remove something else to get at it or am I just blind?
I have a feeling I need to remove the bottom plate in the first picture, but I don't want to do anything I'm not sure of at this point. It looks like there are just a couple of bolts holding it there.
The earlier description of what the flame sensor looks like is accurate, but you might want to google the manual for your model - if you learn that it's behind a bunch of crap, it may not be the home repair for you.
Just a simple metal rod with a cord attached in front of the burner. 1-2 bolts at most.
A few hours later, I venture down to see if I can find the flame sensor to clean it. I pop off the main cover, revealing what I had seen before (http://img818.imageshack.us/img818/1488/75589192.jpg) and then take the two lower bolts out to remove the bottom portion.
This is after I went through all the manuals I have for the furnace, and nothing pointed to the location of the sensor or burners. After the bottom cover is off, though, I see that there are no burners down there. It looks like a big steel drum with a filter or some sort of fan inside it, and that's it. There was a long, thin, metal pole about 2 feet long with a couple bends in it lying on the bottom of that compartment lose, though, so I took it out. It wasn't attached to anything at all, and I am thinking it might have been part of the cleanable filter we have in there at one point.. some sort of removal tool or spring.
Anyway, I put the bottom cover back on, convinced that the sensor is not there, and I am pondering whether or not I should unscrew the plate above (you can see the bottom portion of the plate in the above picture). I decide to leave it, since there is some sort of tape or caulking it looks like, and I don't want to fuck something up. So, I turn the breaker back on and flip the switch. The 90 second fan noise starts up... stops.. the furnace starts up.. and RRRRRTTTCHHHHH again, but this time it won't stop! It's coming from what I am assuming is a fan. It's the big black part in the middle of this pic: http://img811.imageshack.us/img811/2856/76489975.jpg.
I turned everything off, got a flashlight, and went through and started moving wires away from the fan, thinking maybe a label or something is sticking in there. Convinced there are no obstructions, I try again. Same sound! This time, I brave the possibility of explosion and look closely at the fan. If I look down into the central cylinder that pops out of the middle, it looks like there is a small, plastic nub that is vibrating back and forth in there.. almost as if it was designed to make that noise.
Is this some sort of safety feature that has kicked in? What's going on?
Now, I did not touch anything in there. I didn't unscrew anything besides the bottom cover. The only piece I moved was that long metal pole, which was clearly not part of the operating furnace. I'm definitely calling a repair guy first thing tomorrow morning, but I'd like to possibly have some heat tonight. Anything I can do?
Edit: After hours service would cost me $164/hr, with a minimum 2 hour charge. I'll wait until morning, thanks.
Says the venter motor needs to be replaced. Going to be about $600 installed after taxes. He says the problem before I heard the noise couldn't have been the flame sensor because the furnace still stays running.
Edit: Guy just left. $636 to replace the entire venter motor. Looks like a new furnace inside there, but I'm kinda pissed it ended up being this expensive.. especially at this time of year.
Anyway, he explained that the flame sensor couldn't have been the problem, but he showed me where it is. The blowers are actually behind another cover inside the first cover. The tiny one in the picture above with the little circular window. I'll give that a cleaning if it's acting fishy, but it appears to be working now.
I pump up the thermostat to 75 and wait. Nothing from downstairs. I check it out, and the LED code is 14, which is "Ignition lockout."
I'll clean the flame sensor when I get home tonight. I love that I paid this guy over 600 fucking dollars and it still isn't fixed.
Call the guy back, tell him it isn't fixed. If he's not a complete shitnozzle he should be willing to finish the job.
I remember them replacing a motor, and it still has issues. Is your furnace a high efficiency one? Our furnace issue came from improper installation. The two pipes (one in take one exhaust) were installed too close to each other so the intake would get plugged up (with snow). So we have to go clean it out with a coat hanger.
This is what the pipes "suppose" to look like: http://www.checkthishouse.com/wp-content/uploads/high-efficiency-furnace-pvc-vent-pipes-exterior-termination.jpg
But yeah call the guy back, and hopefully he doesn't charge you again
GL!
I'll know of it's fixed or not once I get home, if I walk into a freezer or not.
Also the furnace guy dicked you hard. Completely unscrupulous to replace a $600 part before replacing a $9 one, he just wanted to rip you off basically. If it was a larger company, I'd work my way up the customer service line until you find someone to legitimately complain to.
I dunno about that, necessarily. If the fan was making the kind of noise the OP was describing, it was on its way out anyway. He would've been just as pissed off if the technician showed up, replaced a $9 part, and fucked off without fixing the larger, obvious issue.
The repair guy should definitely come back without charging for a service call again though, since a quick function check should have shown that there was still another problem.
I don't think he was trying to rip me off. I think he just thought I was mistaken about the furnace ever working in the first place for the past few days.
I described the issue to him as follows:
- Furnace wasn't turning on. I had to turn off the switch and back on to get it to start, then it would be fine until it reached temp.
- Suddenly it started making the noise in the fan, so I've kept it off.
He bypassed some switch or something to get it going again, although I wasn't too clear why he did that since it would still start up as usual, it just made that awful noise. He left it going while he went to buy the part. He replaced the part and it started up and he said it's all good. I told him I was concerned all that did was fix the noisy/faulty part, but it would still have the issue I was having before.
He said it shouldn't. He said if it's the flame sensor, the furnace simply won't turn on.
So, before work tonight I turned it all off, took out the flame sensor, involving first disconnecting a vent pipe to move it aside a bit and slowly unscrew the thing all the way at the back all crampy. I was worried I wouldn't be able to get it back in, but that took only half as long as it did to remove it. It wasn't really all that gunky from what I saw, but I took some sandpaper to it anyway and it looked a bit shinier.
So, what else is there that could eventually crap out on this furnace if I've got a brand new venter motor? Doesn't look like there's much else to it.
When I had the bottom plate off, it looked pretty dusty in there. Should I take a vacuum to it? What about the big drum in the bottom? Permanent electric filter? That doesn't need to be cleaned?
I posted originally on my phone, but I wish I would have seen that pic. The burner is at the end of the gas line, in your case a black pipe.