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Heil Furnace Burner Problem

125K views 79 replies 38 participants last post by  gulfcoaster 
#1 ·
I have a Heil DC90 furnace installed in 1999 as a new furnace in a new home. We usually have the blower on during the winter because it helps keep the temperture in the house more balanced. Last winter we did this and the furnace worked fine most of the time, but a few times the pilot would light but the blowers would try to start but go out immediately. The furnace would then just blow cold air until I reset it. The pilot light stayed lit the entire time. I had a service man come out and take a look. He cleaned the ingniter and pilot, but it didn't make a difference. (Note: If the blower is set to auto on the T-stat, the furnace works fine, the problem only occurs when the blower is set to on).
This year I decided to have the service man back to look at it again. I had him replace the igniter. It didn't help. It appears as though the burners are being blown out from the air running through the furnace, like there is an air leak allowing air into the heat exchanger. THe pilot appears to dance around a little if you watch it through little pilot window. The tech said it might be a leak in the seal between the exchanger and the front wall of the furnace. I've read through some of the previous post and didn't find a solution. Anybody else have any ideas? I know I could just leave the furnace on auto, but it worked before and now it doesn't. The service tech is pretty knowledgeable and I have a pretty good understanding of how the furnace works, but this has us both baffled.
 
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#2 ·
I'm having the same problem, but the blower is set to auto. It's happening more and more often. I've had the exhaust fan (blower?) changed and the problem is still there (the fan had a noisy bearing, so it needed to be changed anyway.) Fan starts for 15 seconds, igniter fires and no burn - just see a little flicker through the check window. I'm hoping somebody knows what this is caused by. Haven't found anything online yet.
 
#3 ·
but a few times the pilot would light but the blowers would try to start but go out immediately. The furnace would then just blow cold air until I reset it. The pilot light stayed lit the entire time. He cleaned the ingniter and pilot, but it didn't make a difference.

(confused)

The ignitor is the pilot. The ignitor lites the gas as it comes out of the gas valve.

When you say that the pilot light stayed lit - are you saying the ignitor was glowing?
 
#6 ·
Hi timothyr

It sounds like you have a smart valve set up on your furnace, I this is so the only way to fix this problem is to replace the gas valve. If it does have the smart valve system, the gas valve has the flame ignition and proving circuit built in. And the answer to your next question,they are very expensive.

Good luck, let me know if I can help.
Rusty
 
#8 · (Edited)
I have this same issue.
At times the furnace operates properly but many times once it reaches it preset temp and switches off it won't cycle back on. If I do a power cycle on it it functions as designed until the next cycle.

I am not 100% sure but at the end of the A/C season it seemed to be doing the same thing (obviously it was the A/C not cycling not the heating unit). Would this be consistant with your "smart valve" diagnosis or ?

Thanks in advance.
 
#9 ·
Hi Wolffman

There are many things that cause the problem you are having. Probably the most common for the problem it sounds like you are having is an intermittent limit trip. The major causes of this is either a dirty filter, plugged blower wheel or evaporator coil. The plugged blower wheel and evaporator coil will cause the limits to fail completely if not repaired. This is also a major contributor to early heat exchanger and compressor failure. Unplug your furnace or shut the breaker off to it. Pull the blower compartment door, carefully reach in and feel the vanes of the blower wheel if you pull a bunch of dirt back on your finger. You will need to have the evaporator and blower pulled and cleaned. I am just guessing that this is the problem. If you could give me a little more information I could pinpoint it for you.

Good luck
Rusty
 
#10 ·
#Carrierman thanks for the info.
I have noticed reduced airflow and a whistling like noise also. I replaced the filter ( yes I have neglected to do that on a reg basis like a dummy ) and it seemed to improve but as near as I can recall it is still noiser than previously and noticeably noiser with the filter in.

Any other info that would help on your end just let me know.
Thanks for the help you have already provided. I am going to check it out tomorrow based on what you have said so far and any further advice.
 
#11 ·
Wolffman

It's ok, You would be amazed the houses that neglect their equipment. If you have a HVAC company that you like to use, they will need to pump your a/c down and completely remove the evap coil. I personally like to use the foaming condensor coil cleaner to make sure it is spotless. Make sure if they use this method that they thoroughly wash evap out. The condensor cleaner is not intended to be left on the coil. Make sure they completely dismantle the blower assy and wash the wheel good. Make sure they also install a good quality liquid drier and pull a good vacuum on your refrigerant system. If they are a good company, you will be happy with the result.

Good luck
Rusty
 
#13 ·
Hello, I am a complete furnace novice, although just had a Heil gas furnace/AC installed this past spring. I have had the same issue with the furnace not "firing up" on a consistent basis. My installer told me the following (please excuse my lay person explanation and I am sure he gave me the "dumbed down" version!)...He said he called tech support and that there is an issue with the burners and the air flow. The recommendation was to replace with a improved burner that addresses the issue. When I asked, he said there is not an actual recall on it. So, he changed my burners and I have had not one problem since. It was very inconsistent before and I would have to reset it with the switch to get it to work. It also did not matter if it was actually off and I turned the heat on or if the thermostat tripped it. So, I cross my fingers that I will no longer have problems since it was a big concern to have a problem so fast!!! I hope this makes some sense for you guys and it is maybe helpful!
 
#14 ·
Hi jscho

This is not a hard problem to fix, The particular furnace you have should be hot surface ignition. This is a M shaped piece with a porcelin base. What happens to these is depending on the time and day they were built, rather it be 5:00 on friday before the hangover or 8:00 on monday afterwards. Heil has had some problems with ignitor alignment, now your getting ready to become a service tech and not a novice. First locate your ignitor, the M part of the ignitor should be aproximatly 3/8" away from burner. DO NOT TOUCH THE M PART! the oil from your fingers will cause it to hotspot and fail. The second thing you will need to do is make sure that the M part of the ignitor is positioned in front of the fluted part of the burner (this is the little part that looks like a bunch of fingers around the inside of the burner). Remove the metal bracket and ignitor and carefully bend the bracket to achieve the peramiters I gave you. Make sure that when you reposition it that your power is off to the furnace while doing so and that when you are done the M part of the ignitor is not touching any metal. Once you are done, plug your furnace back in and make sure it fires up every time. The reason most technicians tell you they need to call the factory is they have no idea how to fix your problem. Very seldom does any manufacturer allow a piece of equipment to leave the factory in a unoperable state. The repairs are generally minimal.

Good luck, let me know if I can help further.
Rusty
 
#15 ·
thanks Rusty.
Hopefully this is what my installer did...as long as I have consistent heat this winter and my house does not blow up, I am happy! And, so far, so good. After reading your post, I remembered that he said something about ignitor alignment so hopefully he figured it out! Thanks again. J
 
#16 ·
Well after reading here I took a couple hrs last Sunday and took a look at my furnace. I looked into all ideas that were posted and found that the sensor that is located beside the ignitor on the pilot tube was carboned up. All I did was clean it up with a peice of emery cloth.
Since then everything has been working A1.
Thanks for the help.
 
#17 ·
Thanks for the tips everyone. This should help a lot.

My furnace (Heil DC 90) was also installed brand new in our house in 1999 as part of new construction. I started having issues last winter (of course) just as the temps were hitting the single digits. The furnace would start but wouldn't fire up..then the fan would start and blow cold air into the house. This had happened a few times but, since it was so cold.... To be on the safe side, I called the folks who installed my furnace, and they sent a guy over to take a look at it.

The guy took it apart, looked inside the combustion chamber, and told me I needed a new heat exchanger. He said it would still be under warranty and all I would have to pay was the labor to put it in. He gave me an estimate of $650 for two hours of work. I told him to stick it and got somebody else in to do the same work for 1/2 the price.

Anyway, the heat exchanger was put in and it didn't help at all. As a matter of fact, it started the same thing the very next day. I was so mad at the the whole ordeal (of trying to find a trustworthy repair shop), I said the heck with it, and decided I would put up with it.

Armed with the information you folks have posted here, maybe I will get it fixed right this time. Thanks.
 
#19 · (Edited)
rakes...yes, it does glow orange, and there is flame when the furnace first comes on, but then it won't ignite. Just from what people have been posting here, and from you said, I think it has to be the flame sensor. I think that will be my project this weekend...get that cleaned up.

Any tips or tricks for the non-furnace savvy/furnace repair novice attempting this fix?

Also...has anybody heard of any sort of recall or technical service bulletin on this issue? Sounds like a common issue with this year/brand/type of furnace.

Thanks again for everybody's help and advice on this issue.
 
#20 ·
This is a common issue on all furnaces, because after a long time of use, the combusting gas causes an oxide bulid up on the flame sensor. This blocks the current from passing through the sensor, and the furnace does not know if the gas is burning or not. If its not burning, gas will build up, and could explode, so the furnace shuts off the gas to prevent this. A dirty sensor will cause the furnace to shut down even if the burners light.

It is an easy fix, turn off the power to the furnace, remove the sensor rod, and clean it with sandpaper or steel wool, replace the rod, turn on power and test.
 
#21 ·
I have a problem with my Heil DC90 that is approximately 7 years old. It makes a loud banging noise when the furnace shuts off where you can visible see the back panel of the furnace expand and contract. My service repair person put a brace along the back of the furnace but the problem still exists. The noise is so loud that it wakes me from a sound sleep. The service people at the HVAC company that installed this system are baffeled. Any suggestions?
 
#23 ·
OK...was finally able to get to cleaning the flame sensor on my furnance. Well, actually, I called a friend of mine and he came over and showed me what to do...so he actually cleaned it, but now I know what to do.

Anyway, I am STILL having the same issue. I doesn't happen all the time, but it still happens. There are a couple scenarios:

1). The furnace fires up, the pilot comes on, but gas does not get turned on. Shortly thereafter, the fan kicks on and blows cold air through the house.

2). The furnance fires up, the pilot comes on, gas comes on, flame ignites and, as soon as the fan kicks on, the flame goes out.

3). Everything works fine, the furnace is blowing warm air, then, for no particular reason, the flame goes out.

Anybody have any idea what the heck is going on? Any advice would be greatly appreciated. I'm getting this close to calling up a local furnace company and have them take this piece of :censored: outta here and have a brand new one installed.

Also, anybody know how a person can get ahold of the company that makes the Heil furnace? I would like to call them and/or send them a nice email...and let them know exactly what I think of their furnances and what the chances are of me buying another one (Has something to do with a snowball sitting in a really warm spot).
 
#24 ·
Gas not lighting

I am having a similar problem--can anyone help? The fan comes on for about 1.5 minutes (the air blowing in the house is cold during this time). Then the fan turns off. Next, another (humming?) sound comes from the furnace for ~15 seconds (gas coming on?). A few seconds later, a bright yellow glow is seen in the furnace for a few seconds (HSI lighting), I hear a “click”, then the glow fades away. The humming sound (gas) stops, and nothing more happens. Then I flip the switch to turn power off then on, and the process starts again.

The last time I tried the process, the gas lighted successfully, so the problem is intermittent. Would this indicate a problem with the flame sensor, gas flow, or something else?

If anyone can help, I'll post the solution when the problem is resolved.

Thanks!

 
#25 ·
I just had the same problem. Last Friday I called for service, my furnace was acting the same way as you are describing. As soon as the technician came in and saw it was a HEIL, he automatically said it would be a cracked Heat Exchanger. He used a snake camera and confirmed that it had a cracked heat exchanger. But that wasnlt the problem, it turned out to be the "SMART VALVE" or gas valve.
However, that's not all.. The technician forced me to change the heat exchanger, as it was the law, once he knew there was a crack, he had to change it.There was a danger of getting Carbon monoxide into the house.The good news is that HEIL replaced the Heat Exchanger for free, but the labor was $900.00(3 hours of labor).
So $1,600.00 later, my furnace is running fine, but I'm still looking into this recall issue. If it's that dangerous, then all the houses in my street must get their furnace heat exchanger replaced($900.00) what a scam....

So in your case, look into replacing the Smart Valve...

Good luck!!!!
 
#26 ·
blowing cold air

I have a 9 year old heil furnace and about once every 2 days the blower won't turn off. It just blows cold air dispite the t-stat calling for heat. When the power is shut off it resets itself and cycles normally for a day or 2. I changed the flame sensor/glowplug and it is still doing the same thing. Any ideas?
The old style furnaces were more dependable, they would give you 20 years and when they did give up they were easy to fix. Reading these posts make me think there may be a lucrative career oportunity in furnace repairs.
 
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