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moore70 03-10-2006 10:00 PM

HEIL 5000 Furnace Problem
Sorry if this has already been asked in the past.

About a year ago I noticed that my vents were blowing room temperature air instead of heat. When I turned the Cool/Off/Heat switch to Off, the blower kept running. When I took the lower door off the heater, the safety switch shut the blower off. I looked around for a while and saw a small dark round object (flat on top) that had 2 wires connecting to the top, and a small thing between the two connectors which turned out to be some sort of reset switch or something... because when I pushed it down, I heard a little "click" and when I went back upstairs and turned the heater back on, everything worked fine ever since.

Now, all of a sudden, it happened again last night because my house temp was about 60 degrees when I got up this morning. I used this switch again, turned the thermostat back to heat and heat started coming out the vents again. But when I got home from work, it was locked up again, blowing cool air. I reset it 2-3 times, I hear the heater igniter kick on and ignite, I feel warm air coming out the vent... then when I go check again 20-30 minutes later, it's locked up again.

Any ideas? It is a HEIL 5000 (NUG5100BFA2), A/C and gas heat.

allan 03-16-2006 05:27 AM

flame rool out
This is called a flame roll out switch.

Reasons why it would roll out ?

Dirty filters

Dirty ac coil

If it is a high it could be the secondary heat exchanger blocked

A bocked vent.

Blower motor not turning fast enough .

retricted return air.

Check these first.
If that doesnt work call a furnace repair contractor.

Let me know how you made out.

Allan Thorne
Clarkson Comfort Zone Heating and Air Conditioning Mississauga Ontario

moore70 03-17-2006 07:11 PM

I read your reply, and thanks. I lived here for 5 years (my first home) and didn't realize where the filters were. I finally just NOW started checking and of course the filter in the basement at the furnace was filthy. Dirt and dust actually fell off of it as I removed it. Also, I have a big return air vent in the floor in my hallway and when I removed the cover and looked down in it with a flashlight, there was an inch or two of dust and crud. I could actually hear it starting to suck air as I removed the layer of dirt from on top of the old filter. I don't know how it has moved ANY air this whole time.

So I totally vacuumed out everything inside the duct work, both upstairs and all the way down to where the filter downstairs is, and replaced the lower one with a 3M allergy/pollen/dust type $16.00 filter from Lowe's as well as another for the hallway floor.

Well, the furnace (flame) keeps kicking off and the fan continues to blow until you go downstairs and remove the cover so the safety shutoff switch kills the blower. Then I thought maybe two of those kind of filters don't allow enough air to get sucked in, so I bought one of those fiberglass woven ones you can hold up and see through somewhat... like they're just used to keep some dust from going through, but probably more so for the kid's crayons and big things like that. It still kept kicking off, so I went downstairs and removed the allergen filter from the furnace so that only the cheap, freer flowing filter was upstairs... which should allow plenty of air to get through... but after running several minutes, the gas cuts off still. So I cleaned all the intake out and it has almost no filter in it, so intake isn't the problem I wouldn't think at this point.

There is a vacuum hose I removed because I've heard of them clogging up, and the end crumbled as I removed it, causing it to be too short to put back on, so I went to Lowe's again and bought some 1/4 inch inner diameter high pressure air hose and cut it to fit to replace the old hose. The furnace ignites like it did before so that was replaced but isn't the problem.

After removing the panel so it shuts off, I can replace it, go upstair and turn the heat on, go back downstairs and sit there and watch the flame and hear the fan kick on after 30-60 seconds of heating up.... then it like just cuts off the gas and locks the fan in "on" mode until shut off by removing the furnace cover again, shutting it off upstairs at the thermostat won't work.

I'm not sure about the second coil thing you spoke about. It is in my basement. I think this may have happened the first time in the summer with the A/C running, so I don't think it is a heating only problem. The same reset switch cleared it up that time too. (I'm not positive, but pretty sure it was the A/C the first time.) Any ideas what to check next before calling someone, or is that about all you can think of?

Sorry to go on for so long, but you're the only one I have heard anything from and I'm scared to see what someone will charge me just for coming out to look at it, before they even fix anything. But it is still cold here and I guess we're going to have to dress warm for a while.

Oh yea, almost forgot. For some reason, the furnace ran fine without having to be reset for at least 3-4 days now. It was cutting off, then for several days it has worked fine until it started kicking off today again. It did have both the new allergy filtration filters in place while it ran fine for those last 3-4 days too, so maybe it should suck enough air even with 2 of those type of filters in it.

I can't even find anywhere online where I can find any info about my furnace or where I might be able to find a manual if possible (NUG5100BFA2).

Aceinstaller 03-18-2006 01:29 PM

hey moore,

wecome to the forum.

This isn't the flame rollout switch because your furnace runs through the heating cycle fine. without lockout. The blower will not run after it's time delay during a flame rollout lockout.


check the thermostat. it probably has 2 switches on it. one for heat/off/cool and one for fan on/auto. make sure that the fan on/auto is set to auto.

if the blower still runs go to the furnace circuit board and remove the low voltage wire from the board that is connected to the G terminal. This terminal is the fan on terminal.

if you cycle the furnace and it works fine, then you have a low battery in your t-stat or the t-stat is bad.

if it continues with the problem, then the switch that you mentioned is the fan limit switch. replace this inexpexive switch.(this limit switch is designed to tell the gas valve to shut off while keeping the blower running to cool the heat excanger, because there is not enough return air to keep the heat exchanger in operating tmp during a heating cycle. the dirty filter that you had mentioned is a prime candidate for this limit to become very active and will lessen it's life due to the extreme temps it's been exposed to. now that you replaced the filter, replace this switch and you should solve the problem.)

if the problem still persists, you have a bad board. consider replacing the board or replacing the furnace.(board changeouts are pretty expensive, might make sense to replace furnace if it is getting old.)

good luck,

moore70 03-18-2006 08:45 PM

New switch
I think I'll try a new fan limit switch.

My thermostat is an older liquid-mercury switch type, I don't think it has a battery in it, just the wires. Also, we leave the auto/on switch on auto all the time... we never use ON for anything... we just leave it set to auto and set the temp to whatever we want.

Thanks for the info, I'll get a new switch first to see if that works since you say it shouldn't be too much. For now, I actually removed the wires from that switch and connected them using a very small, skinny nail, to bypass the switch and it works fine now because it can't cut off. I did this HOPING it was just that switch going bad. Hopefully I'm not ruining anything by doing this and it IS just a bad switch. I'd hate to be bypassing it and then find out that it wasn't the switch, but something else causing it to kick out all the time.

Aceinstaller 03-26-2006 07:59 PM

good luck with the new switch.

If it still continues to be a problem, then there is definately a blower speed problem or the sheetmetal is undersized for the furnace, but if it worked for many years, then the new switch should be just fine.

Although if you called a service tech out, he would check the heat rise from the return air to the conditioned air and be able to see a problem like that right away. every furnace has a designated heat rise in which it runs properly and we have the tools and the knwledge to keep your equiptment in tip - top shape. You might be saving a hundred or so dollars now by repairing it yourself, but in the long run, is it really worth it if the unit is running out of it's range and it will need replacing sooner than later?

I wish you the best of luck, but always reccomend a clean and check every season by a professional. Make sure to ask them to do a heat rise check next time you get one.


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