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lionround 11-06-2011 06:36 PM

Heil furnace Model #nugk100dh08
I have a 10 year old Heil Model #nugk100dh08. Haven't had any problems with it prior to this. The exhaust inducer motor was bad, so I replaced the unit. I used the old capacitor because the place I ordered from sent me one that doesn't look like an exact match.

The exhaust blower is working now without vibrating, but I am not getting any heat. It doesn't seem to be getting any gas. I don't smell any gas.

How long after I turn the unit on should I have to wait for it to ignite?

Anything else I should be looking for?


diyorpay 11-06-2011 07:39 PM

ID fans are sensitive and need to be accurately replaced. They spin at different speeds (and 'pull' different pressure amounts) to close a specific pressure switch. They can spin clockwise or counterclockwise etc.

I recommend looking here to match up and ensure you got the correct replacement:

Marty S. 11-06-2011 08:07 PM

Purge time before ignition is usually around 1 minute. Check to make sure any pressure switch hoses are connected correctly. Maybe the inducer isn't spinning fast enough with the old capacitor.

beenthere 11-07-2011 04:21 AM

The new capacitor does have to match the old one. It just has to be the right one for the new inducer. Put the new capacitor on.

lionround 11-07-2011 08:34 PM

OK, I changed the capacitor
OK, I changed the capacitor. I took the vacuum hose off the inducer and put my finger over the hole. I didn't feel any vacuum. I sucked on the hose and then clamped it off with my hand and gas started to flow. Of course, as soon as I let go of it, it shut off again. So, I hooked it back up to the inducer vacuum port and no gas.

beenthere 11-07-2011 09:10 PM

Clogged flue or intake, clogged condensate drain or a cracked heat exchanger.

lionround 11-07-2011 09:16 PM

Heil furnace Model #nugk100dh08
BeenThere, Thanks for all your help. Everything was working fine before I changed the old motor/blower. It was vibrating badly, but everything was working. I am trying not to doubt your suggestions because I have ABSOLUTELY no experience with any of this. However, I have to believe there is something else due to the fact that it was working before and if I apply vacuum to the hose, everything works.

Is it possible the replacement motor is dual purpose and there is a plug inside the vacuum port or something?


how 11-07-2011 09:22 PM

The easy things to check are the...
Check the inducer vaccum port for debris, especially since you didn't feel any vaccum from there. A bit of wire will work. I usually also check the pressure switch ports as well ( your mouth sucking might be enough to work around a partial obstruction but the inducer vaccum may not be as strong). Sucking too strongly on the line to the pressure switch can also ruin the switch.

beenthere 11-07-2011 09:34 PM

Doubt there is a plug. Are you sure its sealed right.

diyorpay 11-08-2011 05:26 AM

Checking the stats of the older fan and the newer fan should provide good info.

See my earlier post. You may have been sold a new fan that can't do the job.

lionround 11-10-2011 11:15 AM

Heil furnace Model #nugk100dh08 SOLVED
Thanks for all your help, especially BeenThere. Apparently there are two vacuum ports, one by the intake and one by the exhaust. I had it plugged into the wrong one. Got it running this morning just in time for our cold snap here in Memphis this week. (My apologies to the people in the Northeast who have had no power for being such a wimp in my 50 degree weather).

Thanks again.

beenthere 11-10-2011 03:07 PM


Originally Posted by lionround (Post 767883)
Apparently there are two vacuum ports, one by the intake and one by the exhaust. I had it plugged into the wrong one.

Thanks again.

You are the only person in the world that has ever connected the hose to the wrong port. LOL...

Hate when I do that, it makes me scratch my head too much. And I don't have but a few strands of hair left on my head.

Glad you got it resolved.

yuri 11-10-2011 04:39 PM

I have the same problem. Saves on shampoo though.:thumbsup:

There may be an orifice plate on the back of the inducer, make sure it is installed properly. On the high efficiency condensing units they are notorious for breaking off.

lionround 12-11-2012 02:55 PM

Well, it's been a year and I am at it again. Same furnace. When I turn on the thermostat, the blower comes on immediately and I am not getting any gas to the burners. Any ideas on where to start would be appreciated.

ben's plumbing 12-11-2012 05:20 PM

can you show us picture of old inducer and new inducer////ben sr

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