Any HVAC guys out there?

[forgop]

My gas furnace sounded pretty sick last night when I was in my man cave. Didn't pay much attention to it at the time and woke up this morning to 59 degree temp downstairs. Pilot light appears to be out. I really didn't do much but take the cover off thus far before I left for church. It's a Bryant 80% 135k BTU downward furnace that I believe is about 6-7 years old.

If anyone would have some expertise in helping me diagnose the cause if it's something other than pilot light going out, please send me a PM with a way to reach you. Will send you some smokes for your help. Will be home around 12:30 EST to start looking at it again.

Thanks!

[maninblack]

Did you try re-lighting the pilot light and going from there?

[shilala]

Smokes not necessary, Duane.
When you relight the pilot, does it stay lit? I'm guessing no.
In that case, it's the thermocouple of pilot generator. It's a cheap fix.
It's obvious which is which, one has a tube coming off it, the other a wire. The trick is getting the right size. Too long can cause problems and too short won't reach.

Thermocouple



Pilot Generator

[shilala]

The fact that it started "sounding sick" makes me believe the induction fan squirrel cage scattered, but there's no reason it'd cut the pilot unless it's tied into the millivoltage circuit as a failsafe.
Another thing that will make the old girl "sound sick" is that your flue could be blocked. Sometimes there's a flapper right where the flue exits the furnace. Pull the flue off, it's a matter of a couple screws. Suck all that crap out with a shop vac.
At that point, you gotta use your head. Does it look like noirmal precipitation, crust and rust, or are there pieces of pinecone and junk in there that shouldn't be there?
If the second is true, you probably have critters working in your flue and you need to take a look.
If your flue exits near the foundation and you guys have lots of snow, go shovel it out and make sure the snow and ice hasn't backed up the flue or created a plug or just piled against the flue. That'll solve the problem.
If a low pressure limit shut down the pilot circuit, you may need to correct the flue problem before the pilot will relight.

If this stuff doesn't work, suck it up and call the furnace guy. If you can run SAFE temporary heat until tomorrow, it'll be a lot cheaper. Furnaces are designed to break on Super Bowl Sunday. It's because no one is available to fix them, and if they are, they'll charge you an arm and a leg.

[forgop]

Thanks for the suggestions thus far. As I said, I just took the cover off and took a quick peek. Will give this a shot when I get home.

[RGD.]

Originally Posted by shilala

The fact that it started "sounding sick" makes me believe the induction fan squirrel cage scattered, . . .

Since there are no other moving parts - the cage would be the first suspect for a "sounding sick" furnace.

A 6 year old Bryant may not have a pilot light - it may have electronic ignition instead. If both covers are off and you see a circuit board with any lights on it - it's electronic and will most likely have to call for service.

Set the thermostat to fan only and see if the fan runs or makes noise.

Make sure the filters are clean - dirty filters will cause a thermal shutdown.

Try re-lighting the pilot if it's not electronic. Otherwise do as suggested and replace it. Take it out and take it with you.

A picture or two would help.

Good luck with it.

Ron

[14holestogie]

Originally Posted by RGD.

Since there are no other moving parts - the cage would be the first suspect for a "sounding sick" furnace.

A 6 year old Bryant may not have a pilot light - it may have electronic ignition instead. If both covers are off and you see a circuit board with any lights on it - it's electronic and will most likely have to call for service.

Set the thermostat to fan only and see if the fan runs or makes noise.

Make sure the filters are clean - dirty filters will cause a thermal shutdown.
Try re-lighting the pilot if it's not electronic. Otherwise do as suggested and replace it. Take it out and take it with you.

A picture or two would help.

Good luck with it.

Ron

Those were my first thoughts, as well. I'd start with the filter, or the easiest fix first.

[14holestogie]

Originally Posted by shilala

If this stuff doesn't work, suck it up and call the furnace guy. If you can run SAFE temporary heat until tomorrow, it'll be a lot cheaper. Furnaces are designed to break on Super Bowl Sunday. It's because no one is available to fix them, and if they are, they'll charge you an arm and a leg.

Unfortunately, this is also true. I had an electronic ignition replaced a couple years back on a Sunday. They not only charge you extra for the service call, they scalp you on the parts as well. $150 just to get them in the door and $75 for a $15 part.

Got the next replacement, if needed, off the Bay for $15. I also have a screwdriver and the 15 minutes it'll take to change it.

[Mattso3000]

If it is electric, take a look at the ignition before you get it replaced. I had the service technician come in and charge me $120 just to scrape a little corrosion off of mine last year.

[shilala]

80+'s generally have a standing pilot, or at least they used to. I haven't done this for a living for a long, long time.
90+ and all the other crap, electronic ignition.
The standing pilot is part of what brings the furnace down to 80+

You guys are right, "sounding sick" doesn't leave a whole lot to go on.
I checked the weather in Indianapolis and it's only supposed to get down to 28 tonight. Some space heaters and stuff will get the house warmed up.

Duane, do NOT disperse space heaters and leave them on while you go to watch the game, if you were planning to go out. It's the best way to come home to a pile of rubble. Either stay home and guard the house or shut them down before you leave.
Please don't take a chance. It isn't worth it, and I can personally think of at least half a dozen people who have toasted their houses because of a Sunday (or late Saturday) furnace breakdown.

[T.G]

Scott, my mid-90's Carrier furnace uses a hot surface ignitor to fire the pilot which in turn ignites the burners, so when you look at it, if you're not familiar with the parts, it might appear as if the pilot is out, when, in fact, it's not supposed to be on.

I'm not familiar with the Bryant designs but generally speaking, most modern furnaces have a self-diagnostic routine of some sort built into them where they will spin up fans, close power relays, actuate solenoids, etc all in sequence and you watch for or read your DVM to see what isn't working. If it's not outlined on a service diagram inside the access doors, you can use the exact model number of the furnace to find the manual online at the manufacturer and see how to trip the diagnostic and it's sequence timing. Depending on what that comes back with, take it from there.

Please remember to close the gas shut-off valve to the furnace before starting any diagnostic routines or service.

[T.G]

Actually, don't mess with it until you verify it's status as if it's only 6 years old, it might still be under warranty:
http://www.bryant.com/support/warranty.shtml


If it's something like a hot surface ignitor, then bfd, those are cheap, the labor to have a tech install is going to be 4-5 times what the warranty part would cost you to buy outright and just install yourself, but a blower motor or worse, a circuit card, those are big dollar parts.

[forgop]

Appreciate the help thus far. I blew out the filter-it had some stuff in it, but it wasn't horrible by any means. It appears that this is one of the newer models that doesn't have the ability to just relight.

I took a short video and posted it to youtube for reference. Around the 15 second mark is where I flipped the fan switch. The status code LED seems to be "telling" me something, but I don't know what the heck it is.

http://www.youtube.com/watch?v=vqQf4U7L9Hw

As far as priority on this, it's not a HUGE deal at the moment. This furnace heats our first story and doesn't run very much as I have it programmed only to run for maybe 2 hours in the morning and 2 hours in late afternoon as it's not a primary living area at all. Outside of cooking/eating, we don't spend much time down there. Temps over the next 10 days are as low as mid-20's and I can always throw some wood in the fireplace for a bit if it gets really outrageous down there.

Part of me is really wondering if this is overkill now that I made it just a first floor only unit. It's a 135k BTU furnace and it's only used to heat about 2200 sq. ft, so in the event it's overkill, the short cycling won't do itself any favors over the long haul either. Plus an 80% furnace isn't one I'd want to sink much money into.

[forgop]

Originally Posted by T.G

Actually, don't mess with it until you verify it's status as if it's only 6 years old, it might still be under warranty:
http://www.bryant.com/support/warranty.shtml


If it's something like a hot surface ignitor, then bfd, those are cheap, the labor to have a tech install is going to be 4-5 times what the warranty part would cost you to buy outright and just install yourself, but a blower motor or worse, a circuit card, those are big dollar parts.

I can't remember the age for certain. The furnace originally had a vent feeding the 2nd story right next to it, but when I added a new central air/furnace for upstairs last summer, the duct was removed that had the sticker on it from the original owner as to when it was purchased and their service schedule. May have to call Bryant and see if they show it registered before I hassle the previous owners as to who they bought it from.

[T.G]

311AV? Fan sounds fine, look up the blink code and check the hot surface ignitor located by the pilot light, see if it has a hole burned through it.

When you run diagnostics, or even just close the gas valve and then kick the thermostat to heat so that the furnace tries to come on, it should glow bright orange changing to white. Then the solenoid for the pilot will open, lighting the pilot.

Hot surface ignitors burn out - they wear through, especially if the furnace cycles on and off a lot.

Will try and find a photo.

If it's not the ignitor, call a tech.

[T.G]

Your furnace might use an ignitor that looks like these, they were used by just about every furnace manufacturer at one time or another. The one below has failed




If it's not an ignitor burnout, which does happen, then you might have to call a tech.

[forgop]

Originally Posted by T.G

311AV? Fan sounds fine, look up the blink code and check the hot surface ignitor located by the pilot light, see if it has a hole burned through it.

When you run diagnostics, or even just close the gas valve and then kick the thermostat to heat so that the furnace tries to come on, it should glow bright orange changing to white. Then the solenoid for the pilot will open, lighting the pilot.

Hot surface ignitors burn out - they wear through, especially if the furnace cycles on and off a lot.

Will try and find a photo.

If it's not the ignitor, call a tech.

Yes, it's a 311AAV. I've tried using google to help me find a resource for determining the code, but I haven't turned up anything other than generic stuff about the model having a self diagnostic feature. I just haven't found anything that comes up with what the sequence means.

Just curious-if it's the ignitor, is there any possible noise associated with it going bad? Just wondering if there's an explanation for the noise it was giving. It was kind of a squealing noise of sorts, not a real high pitch or very loud, but just one you recognize shouldn't be there.

[shilala]

They use hot surface ignition on lots of stuff, Adam. My boiler in my last house used one. I always kept two on the shelf, they burned up regularly.
I'll watch the video before commenting any further, but my guess is that the fan induction motor is borked. It's not making the pressure switch and that's holding out the whole ignition system, which it's supposed to do.
If there's an electronic ignition control, it'll code, but it means nothing.
Duane, you might be able to restart the unit by turning the tstat all the way down, turn off the breaker for 5 minutes, flip it back on, and turn the t-stat back up.

[shilala]

I couldn't make nothing out at all from the video. I tried to see what kind of ignition system it was, but I got vertigo. Lol.
Regardless, it is what it is, Duane. You're in good shape with your alternate heat. Get it fixed when you can. Try to find someone you know who can do it for you and save a few bucks.
At 6-7 years old, the burners should be pulled and washed, too. That's not a big job, but it really should be done, especially if you already have a guy there.
Wish I could be more help!!!

[14holestogie]

Originally Posted by shilala

Duane, you might be able to restart the unit by turning the tstat all the way down, turn off the breaker for 5 minutes, flip it back on, and turn the t-stat back up.

I've done this in the past. Had issues with my set-back thermostat. The furnace would run long enough to raise the temp a couple of degrees, but then kick out. Restetting would get it running again for a couple more degrees, then kick off again, followed by the blinking led. Solved it by raising it slowly to the desired temp and don't use the setback function any longer.