[mviker]

I'm having some trouble with my normally great Carrier Weathermaster 3000 furnace.

Every year, once it warms up enough, I shut off the gas supply to my furnace using the valve in the closet connected to it and install a small jumper between the green and red wires so the fan is on all summer. I have no central air, so this helps keep the air moving and provides the illusion of cool on those hot summer days. Once fall approaches (Right about this time), I reverse the procedure and fire up the furnace for the winter.

Well, Last night, I took out the small jumper and turned my gas back on and turned the thermostat up to where the furnace should kick in and start. I got nothing. After double-checking, I tried again and this time, the fan came on and ran for about 5 minutes, but the furnace made no effort to ignite and start heating. I turned the thermostat back down so the fan should have shut off, but it kept running, so I shut the power to the furnace off and checked everything again. Looks ok, so I turn power back on and try again, but this time, no fan either. I noticed a 3 amp spade fuse on the circuit panel inside and tried pulling it out, but thanks to my clumsiness, lost as it flew out of my hands off into the ether, so at this stage, I'm dead in the water until I get a replacement fuse.

So today, I hit an Auto parts store and bought some 3 amp fuses. They look the same to me as the ones in the furnace, so I think I should be good to go for it again tonight after I get home from work.

Just a few questions...Do any of you know what might be the cause of the trouble? I do have a buddy that said it sounded like maybe the ignition part of the gas wasn't working or sensing gas. Is there a reset for this thing? I'm planning on putting in the new fuse, then cleaning the innards thoroughly, then trying again, but it's be nice to have a few suggestions as to what may be the culprit here. I've been doing this for at least the past six years and have never run into this trouble before. The furnace in my opinion, seems to be fine and isn't too terribly old, maybe 10 years? I don't recall when I had it installed.

Any suggestions as to what to check or look into would be greatly appreciated.

Thanks,

Kevin

[Trulyvintage]

Join & post here http://www.diychatroom.com/f17/





Jim

[6t7gto]

does the pilot light?

[6t7gto]

If the pilot lights, then the exhaust inducer must come on before the main burner will light. providing you have an exhaust inducer.

[6t7gto]

You sure it's a 3000. I can only find info for an 8000.

[mviker]

Originally Posted by 6t7gto

You sure it's a 3000. I can only find info for an 8000.

I'm fairly certain it's a 3000, but with my vision, it could be anything. lol!
I will have a look again once I'm home, but pretty sure.

It's got an electronic ignition thing, so no pilot light, but I didn't even hear it attempting to ignite the whole time I was fiddling with it, The only thing that did come on was the fan before I lost that darn fuse. Gonna replace the fuse tonight and see what happens after I get home. There's some dust built up in there I want to clean out as well. I clean it once a year too. Hoping to be good to it, but it's obviously not happy about something.


Edit: Oh...There's a red LED light that's blinking also. Dunno if that means anything. Could be the self destruct warning light for all I know. Never noticed it blinking in the past. I think it's supposed to just be on solid. The light is on the circuit board near where the fuse is supposed to be. It was blinking BEFORE I lost the fuse as well as after.

Thanks!

Kevin

[65WJ]

clean your flame sensor.

patrick

[mviker]

Originally Posted by 65WJ

clean your flame sensor.

patrick

Patrick,

Is this something even a caveman can do? Not sure what that is or where it may be. Is it part of the ignition thing? I see where the gas goes into a module type thing, then the tube runs down to where there should be flame. Maybe down there?

Sorry to be so ignorant. lol

I am planning on cleaning everything thoroughly, so It'll probably get done whether I know it or not.

Appreciate the advice.

Kevin

[mviker]

Originally Posted by 65WJ

clean your flame sensor.

patrick

Patrick,

Found a couple Youtube videos that address what you mentioned. Will follow the instructions and see what happens.

http://www.youtube.com/watch?v=Ecd5CzJjss4

http://youtu.be/I86joWL66aE

Thanks much for your advice!

Kevin

[george kujanski]

You also need to find out whether the fuse was rated for 110V or a lower value like 32V.

A lot of automotive fuses are rated 32V and those should not be used in a 110V application.

There is usually a schematic diagram pasted to the inside of a metal door. Take a pic of the schematic with a good camera (a phone cam may not be good enuf) and post it here.

George

[65WJ]

also check the vacuum tube. I forget what it does but if there is not vacuum the pilot will not light. We had that problem on the furnace at work. I went to Menards and bought a larger fitting and used jb weld to hold in place. once cured, hooked the vacuum hose up and we had heat.

patrick

[mviker]

Here's the latest....

I cleaned the furnace and also the heat sensor and replaced the fuse. The fan does come on, but the heating element does not come on.
Patrick... I also checked the tube you mentioned. I can activate the diaphragm sucking on it and there is no blockage blowing into the furnace either, so I think that's ok.

I did mention the flashing LED. Found some stuff online at http://www.diychatroom.com/f17/ (Thanks Trulyvintage) that says to check the polarity if it's blinking steadily, which it is. I'm not quite sure what to do about it though. This error apparently disables the gas until it's fixed so I think I know the problem now. Reverse polarity and I may be back in business.

By the way...6t7gto, you were right. It's a Carrier WeatherMAKER 8000. Sheesh! How blind am I? lol

Here's the manual. It refers to a twinning kit to reverse polarity, but that almost sounds like running two units in tandem or something.

http://www.docs.hvacpartners.com/idc.../58d,u-8sm.pdf

I'm getting closer. Gotta figure out this polarity thing and why it happened after all the time I've had the furncae.

Kevin

[mviker]

Originally Posted by george kujanski

You also need to find out whether the fuse was rated for 110V or a lower value like 32V.

A lot of automotive fuses are rated 32V and those should not be used in a 110V application.

There is usually a schematic diagram pasted to the inside of a metal door. Take a pic of the schematic with a good camera (a phone cam may not be good enuf) and post it here.

George

George,

I found some online manuals for the furnace and one mentioned to use standard automotive type fuses, so I should be fine there. This polarity thing has me dumbfounded. Not sure what to do about it. I read another post in the DUY site that says if the fan comes on after jumping the red and white wire, it's a thermostat problem. That's the case with mine, so I spent some time playing with the thermostat also. I don't see anything wrong with it though. There are four wires and they are connected properly. Can a thermostat go bad and look fine? Nothing is obvious with this problem.


The sticker innfo you mentioned is also in the links I posted. The flashing LED is where I determined I have the polarity problem from the description on that furnace sticker and in the links. It flashes steadily. No short ot long flashes, just continuous regular intervals. According to the info, that's a polarity problem.

Kevin

[mviker]

One last thing...I'm beginning to wonder if maybe the mainboard may have an issue from a storm that hit earlier this year that blew out my phone, TV, stereo, and Internet equipment. At the time, I had the furnace wired for fan only, so I wouldn't know if the board was fried until now. There was a lightning strike close enough to the house that fried a bunch of my electronics. Maybe it got the mainboard also and this polarity thing is related to that.

[beemergary]

If the furnace comes on the thermostats ok. Do you hear it trying to ignite after the fan comes on? Look at the front and back of board. You may see where it nuked itself.

[mviker]

Originally Posted by beemergary

If the furnace comes on the thermostats ok. Do you hear it trying to ignite after the fan comes on? Look at the front and back of board. You may see where it nuked itself.

Gary,

No. I don't hear or see the ignitor even attempting to come on. The fan will run for a few minutes, then shut s back off. The flashing LED is telling me this is a polarity isse according to the error codes. Since there is no obvious way to set polarity, I'm thinking the board may be toast. The from has a plastic cover that looks like it's not meant to be removed. I haven't the board from it's mount, but may do that tonight to have a look.

At this stage, I think I've ruled out the thermostat despite what I read about jumping the red and white wire. Connections all seem fine there. The flashing LED is difficult not to believe, so my inclination is the mainboard or polarity issue.

Kevin

[mviker]

Ok,

I signed up at the DUY Forunms and got a lead to check into. Seems I should confirm all my grounds are intact. That's a possible reason I'm seeing the polarity code with the LED. Gonna look into that after I get home from work.

[beemergary]

An older furnace is kinda simple-thermostat calls for heat-red wire makes contact with white-furnace starts-if flame sensor don't see flame-shuts off furnace-furnace lights and when reaching a pre set temperature (stack control or heat control) turns on blower motor-when thermostat reaches a pre set temperature shuts off flame and fan runs till furnace cools down too a pre set temerature set on the (stack control) also there's a hight limit on the stack control (safety) in case furnace gets to hot. If someting does'nt go right just push the reset. The newer ones have a fan that blows out the combustion chamber before ignition and a board and othe high tech bull crap.

[John V.]

You may have already come across these in your own searching, but thought these threads could be useful:

http://www.doityourself.com/forum/ga...t-furnace.html

http://www.doityourself.com/forum/ga...-not-heat.html

On occasion, I've had electronics (not a furnace) "freeze up" after a lightning storm, especially when the power flashes it seems.

I've had some luck by tripping the breaker on a given circuit and for whatever reason, the device will start working again after I reset the breaker.

But you indicated you've already cut power to the furnace, I assume by tripping the breaker.

Could be grounds and I suppose you could try reversing the low voltage leads as suggested in the 1st link. But that was a new install. Don't know electrical enough to know if polarity can magically reverse without actually swapping wires around (including I guess the main wiring to the house?). Your situation sounds most like the guy in the 2nd link. He had a bad board.

Hope you figure it out!

BTW, I love the fuse into the ether. I've been there before.

[GT182]

I just went thru the same thing with my gas furnace Kevin. I cleaned all the probes and it's working great again.

Also make sure you blow the dust out of the exhaust fan unit too. Mine ended up stuck on about 3am a couple of days ago. I shut off the power to the furnace and cleaned it after I got up and went for coffee that morning. Working fine now.

And spray some lube oil in the pulley bearings for both of the fans. Mine started to sound like they were coming apart last year, but some good lube oil saved them both.