Heil Furnace Problem.


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Old 11-24-09, 03:48 AM
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Heil Furnace Problem.

Hello all. Have a 1993 Heil Direct Vent furnace that was trouble free until last winter. The inducer motor would squeal very loudly upon start up. Found one on line and swapped it out. All was well the rest of the season.

As of a month ago it developed a problem again. The furnace would just abruptly shut down. By that I mean the blower motor would shut off and the flame would go out. There would also be a burning smell coming from the vents.

Upon inspection I could here the inducer motor buzzing. As if was getting power but would not run. Kill the power. Let the furnace cool down and it would fire right up later.

The second time it did this (a couple days later) I decided to replace the run capacitor for the inducer motor. Everything was good for 4 1/2 weeks and then it did it again.

Any ideas? All and any advice would be much appreciated. Thanks.
 
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Old 11-24-09, 05:23 PM
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Capacitor

If the original cap was weak it could have damaged the motor as could a replacement not of the correct microfarrad rating. It sounds like you need a new motor & cap.
 
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Old 11-25-09, 01:16 AM
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That was kind of my thoughts as well. In hind sight I would of bought a new Run Cap with the new motor purchase.

The OEM Cap was a 5mfd 370v. That is the same one I went with after the new inducer motor acted up this year twice. To much to late I fear.

On a side note the OEM Cap was a made in the USA unit. The only replacement I could find was a made in China brand. The replacement CAP was physically the same size but weighed half as much as the OEM unit. Cheaper? Less reliable?

Not sure if I could connect an amp clamp and learn anything on the condition of the motor. It still runs and sounds smooth.

It still kind of baffles me that the furnace just shuts down abruptly when the induced motor stalls. I would of thought that the main blower motor would continue to run as to remove the heat from the exchanger and then time out.

Any suggestions on where to purchase another motor and cap? Searching the net these things really range in price.
 

Last edited by 3834B; 11-25-09 at 02:32 AM.
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Old 11-25-09, 03:43 PM
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Offshore Cap

You can bet that lightweight cap is not going to hold up. I've had too many apples out of that basket but good luck in finding one made in the USA.

I can understand the burners shutting down but not the circulating fan. Makes me wonder if there aren't other electrical issues, like maybe control board??
 
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Old 11-25-09, 06:46 PM
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Originally Posted by 3834B
Not sure if I could connect an amp clamp and learn anything on the condition of the motor. It still runs and sounds smooth.
My guess is it will give you some number that is about right, as long as it sounds like it is running right.

It still kind of baffles me that the furnace just shuts down abruptly when the induced motor stalls. I would of thought that the main blower motor would continue to run as to remove the heat from the exchanger and then time out.
I can't remember off the top of my head if it should keep running. Anyone else? If not, I will have to pull off a PS vacuum line and refresh my memory that way. Ya. That could be a big clue, if the blower also shuts off, as to what the cause might be. Not sure either if furnaces with fan timer boards would be the most likely to go out when the inducer goes out prematurely. You really wouldn't thing so, since the stat shuts down the inducer, yet the blower contines to go.


Any suggestions on where to purchase another motor and cap? Searching the net these things really range in price.
You'd want to first make sure that power is still trying to get to the inducer. If it is not even getting there, then you have some other issue.
 
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Old 11-25-09, 07:04 PM
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Is this the inducer assembly you need:

Heil ICP Tempstar 1011350 Draft Inducer Motor A173 - eBay (item 380173344751 end time Nov-30-09 09:22:50 PST)


I happen to have one left over from my furnace repair business.
 
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Old 11-26-09, 05:46 AM
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You'd want to first make sure that power is still trying to get to the inducer. If it is not even getting there, then you have some other issue.
I did indeed confirm there was proper voltage when the motor quits/stalls and just hums.

I also removed one of the wires going from the motor to the Run Cap and turned the furnace on. The inducer motor would just set there and hum in this scenerio as well.

I am considering running one of the Run Cap wires through a manual switch so while the furnace is in operation I could momemtarily interupt power to the Cap to see if the furnace goes into complete shut down mode. This scenerio would simulate the Run Cap falling off.

I would also mention when I removed the old Run Cap about a month ago I used the screwdriver method to discharge the stored energy in the Cap and did not get so much as a flicker.

I also Ohmed out the old Cap and the resistance was infinite. It is very possible the new motor ran with a weak and failing Cap all last winter and the ill affects are rearing now.

This is in contrast to when I just removed the new Cap the other day and it had plenty of stored energy i.e. big spark when the terminals were shorted.

Is this the inducer assembly you need:
Sure looks like it. Thanks. I dug out my records and found one at the same company as I purchased the last one for a little better price. I also ordered a new Run Cap as well.
 
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Old 11-26-09, 09:20 AM
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Well, wired a manual switch in series in the circuit with the Capacitor and discovered a couple of things.

1. The inducer motor will not START without the Capacitor in the circuit. It will just set and hum. (I also proved this yesterday by unplugging one of the leads before start up).

2. By turning the switch off when the inducer motor is running the inducer motor will continue to run. (I will note that the pitch of the motor changes and the RPM seems to reduce a little. Here's where I would of liked to of had an amp clamp for the test).

I guess my questions are could it in fact be possible that this new motor was internally damaged and weakened by running it with a possibly weakened Capacitor? That it eventually gets overheated and stalls?

Also, I proved that the motor will not start but will run without the Capacitor. So, is it a RUN or START Cap?
 
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Old 11-26-09, 11:20 AM
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Run or Start

It is a run cap. If you were able to apply power to the motor & give the fan a spin, the motor would start & run albiet slower than normal.
 
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Old 12-02-09, 05:26 AM
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Well, I have a new inducer motor and made in Canada Run Cap in my pocession. Kind of leary about just hooking it up not knowing for sure that is the problem. Wouldn't really want to ruin a new motor due to a problem existing elsewear.

The furnace did it's thing again this AM while I was sleeping. Woke about to a strong electrical smell and the inducer motor was just humming/buzzing. It was not hot to the touch though. I couldn't get it to act up for over a week when I had test equipment in my hands.

Anyway, I did notice that even when I turned the thermostat switch to the off position the inducer motor still was making noise. Not until I killed the breaker did it stop.

I don't have the schamatic in front of me at this time but I do believe one relay controls the blower motor and the inducer motor. It has either six or eight terminals on it. Seems like it would be a cheap investment.

In the meantime I was going to wire the inducer motor to direct 110 and connect an amp clamp. If the inducer motor is weak and failing it should just quit at some point. If it sets there and runs an hour straight without issue I would think the problem is elsewear.

Would this make sense anyone?
 
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Old 12-02-09, 06:08 AM
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Originally Posted by 3834B

In the meantime I was going to wire the inducer motor to direct 110 and connect an amp clamp. If the inducer motor is weak and failing it should just quit at some point. If it sets there and runs an hour straight without issue I would think the problem is elsewear.

Would this make sense anyone?

Yes, although you reported earlier that you had checked and found the voltage supplied to the motor normal when it was failing to operate properly.

I'd double check that again as well.
 
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Old 12-02-09, 08:28 AM
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I do plan on checking the voltage again. I was kind of standing on my head the first time while the wife held the interlock switch and read the meter. It was fluctuating some but would hit the 120's. I thought allot of that problem was likely the meter probe connections.

I have since made a (break out harness) to connect in series so I can get a hands free steady reading and also have the cover in place as to hold the interlock switch.
 
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Old 12-03-09, 05:39 AM
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Ran the furnace hard for five hours yesterday afternoon and it had one hiccup. With the volt meter connected to the inducer motor via a couple of (break out harnesses) on one occassion I could here the control relay click that supplys power to the inducer motor and pressure switch and power was momentaraly interrupted.

When this happened the burner went out and then refired. At this point the circulating fan was not running yet. Otherwise, could not get it to fail again but I am sure it will.


I stated earlier in this thread that it was baffling that when the inducer motor would quit the main blower motor would just abruptly shut down as well. A member here then stated,


I can understand the burners shutting down but not the circulating fan. Makes me wonder if there aren't other electrical issues, like maybe control board??
After studying the schamatic harder there is a common denominator between the inducer motor and the blower motor and that would be the TRANSFORMER.

It supplys 24VAC to both the inducer motor relay and the blower motor relay.

When failures happen the entire house smells strongly of electrical. When it first happened it was pure panic. From what I have read transformers have a very strong smell when they get hot.

I thought is was the inducer motor smelling but it never felt hot to the touch. Could it of been the transformer that is hot/smelling and humming all along? I really need it to happen again to test this theory.

In the meantime there is a slight hum coming from the transformer all the time. Not sure if I have ever noticed it in the past or if this is normal.
 

Last edited by 3834B; 12-03-09 at 06:44 AM.
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Old 12-03-09, 08:03 AM
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(I just lost a post due to some About Blank pop-up. OOOOH I get mad at wasting my valuable valuable time!!!!!)

If the inducer motor 120 volt power goes away along with the fire, then yes, if certain 24 volt power fgoes away, that may even affects the thermostat receiving 24 volts, then this could stop it(the inducer as well). What would be happening is it woud shut off a 24 volt X 120 volt relay to the inducer. If you can try to do many forced back to back to back to back calls for heat, and see if you can make it fail, then use voltmeter and see if even power from low voltage (24vac) terminal R to C(common) gets interupted(stopped). IOf not, then try W to C (during failure). IF not here, then it likely be in the board or a bad wire connection.

But first, maybe you could learn something by testing the line and load side of the transformer. See if you have 110-120 volts coming into it, and see if you have about 24 volts coming out of it, by testing across the wires. Since it works sometimes, and not other times......if it be the transformer's fault, either you might have low voltage that is marginal, or, you have something really strange going on where there is a break in a transformer coil winding that somehow connects or disconnects itself, due to furnace vibrations or something.
 
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Old 12-03-09, 02:11 PM
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Transformer

"After studying the schamatic harder there is a common denominator between the inducer motor and the blower motor and that would be the TRANSFORMER."

By George, you might be onto something there. Shut down the power & give the transformer the old sniff test. On some equipment the transformer is on the board, others are separate.
 
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Old 12-03-09, 02:22 PM
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I can't recall ever encountering a transformer that caused intermittent operation of a furnace. Usually they either work or are burned out.

I'd certainly inspect the transformer for any sign of it having overheated or an odor like it was overheated.

Also, is the a fuse in the circuit board? If so, the fuse usually protect the transformer in my experience.

No harm in checking out any reasonable suspicion of course ---you never know until you check.

This is apparently the Heil/Tempstar Model NUGK condensing furnace. I'll have to see if I can find a circuit diagram since I can't remember the details of the circuit of this furnace, although my recollection is that it uses a Honeywell intermittent pilot ignition system.
 
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Old 12-03-09, 03:09 PM
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This is apparently the Heil/Tempstar Model NUGK condensing furnace.
The model is (NUGS075BG03) Direct Vent Condensing Furnace.
 
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Old 12-03-09, 03:44 PM
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Here a manual that might be fairly close to the one we are discussing.

The wiring diagram is on page 59.
 
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Old 12-07-09, 05:39 AM
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Guys, I think my furnace problem is cured. It turned out to be the main circulating motor.

I unintentionally made this harder for members here to diagnose because I was sure it was the (Inducer Motor) that was humming/smelling.

Long story short the furnace finally acted up again Sunday morning. Strong smell coming from the vents and a buzzing/humming noise as well.

Spring out of bed and rush down the stairs only for the noise to stop the second I got to the furnace. The exterior sheet metal around the burner area was very warm.

Ran back upstairs and using my heat gun I aimed it at a register and the radiant heat temp was 110F. It was obvious the burner went through a cycle or two and the ciculating motor did not come on.

Ran over to the thermostat and moved the heat switch to off and manually turned on the circulating fan as to removed heat from the exchanger. But what is this? The circulating fan will not run?

Ran back down stairs and pulled the cover that exposes the circulating fan and holds the interlock switch in. The minute the cover was removed I heard a click. It was the circulating fan relay.

Pushed the interlock switch back in and the circulating fan relay closed as to energize the fan but the fan did nothing. I touched the fan motor and you could of fried an egg on it.

Held the interlock switch in and I began turning the circulating fan in the direction of rotation. After about 30 seconds the fan took off and ran. I continued holding the interlock switch as to cool the burner and fan motor.

After this incident the furnace again worked normally.

Later in the day I called the guy we purchased the furnace from 16 years ago and he said he had a three year old fan he would give me. Met him at his shop and he hooked me up. He also tested the RUN/CAP and it passed.

He figured the motor likely had a bad spot in it and when it stopped at that area it would not take off. He also stated the likely reason it quit buzzing was a built in (thermal limiter) opened.

Put the motor in he gave me and the furnace was now running much quieter. Plan on getting the season out of this motor and replace it with a new unit in the spring.

Also plan on hiring the same guy for when the furnace will someday need replaced. That was great service. The new inducer motor I purchased can also be sent back.

Nothing like a happy ending. Would also like to thank everyone at (Do It Yourself). Thanks for the help guys. We have 25 below coming tonight. Perfect timing.

On a side note we relied on a gas wood stove that reqires no electricity to operate. Did not feel comfortable leaving the furnace run unattended when it had issues and with nobody home. That was a real life saver. If you are in cold country a back up is almost a must.

Drinks all around. Rum for my friends.Beer 4U2
 

Last edited by 3834B; 12-07-09 at 06:16 AM.
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Old 12-07-09, 06:42 AM
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Good read. Glad you got it.

25 below? Cold weather is supposed to come here Thursday I think. But not quite that cold. Only about 4 below.
 
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Old 12-07-09, 07:42 AM
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Glad you got things working.

However --- does the fan motor have oil ports on it? Was the motor hard to turn when you pushed it by hand?

If so, it's quite likely that the motor failed for lack of lubrication, and you can be headed towards the same thing if you didn't lubricate both oil ports before installing the replacement motor, which can require disassembly of the fan assembly.

No oil ports? Never mind!
 
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Old 12-07-09, 09:05 AM
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Sealed bearing. The old motor also turned easily. I think old age killed it.
 
 

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