# First time furnace repair. Any advice?



## klas (Apr 6, 2009)

Issue was resolved


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## DangerMouse (Jul 17, 2008)

hi and welcome to the forum. i'd look in the direction of the switch first. cut the power first and check the hoses for debris or water. blow in and out to see if it's working. turn power back on, check for 24v at the switch.

DM


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## klas (Apr 6, 2009)

Thanks for your reply! 

Board needs replacing either way. You can see damage on the picture. 

Can you tell me where can I order replacement pressure switch? The one I have is Tridelta FS6089A-1912. Can I get different brand? Like this one:

http://cgi.ebay.com/Lennox-87H9301-...-20055506_W0QQitemZ220370327395QQcmdZViewItem


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## yuri (Nov 29, 2008)

The pressure switch you have is -.50"WC and that Lennox (actually AireFlo one) is -.40 "and the wrong one. I doubt if it is the pressure switch as usually you only get one failed part at a time. Tridelta has gone out of business, Honeywell makes most of them now. Probably have to get it from Trane due to the mounting bracket etc. The yellow part on the board is burnt. I would NEVER buy parts on EBAY as it may be used/faulty. My cost on those boards is at least $150 so you won't get it cheaper and be new. Buyer beware.


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## hychesee (Oct 31, 2008)

Very strange for both the draft inducer pressure switch to go bad and the control board to short out. In the board picture it looks like a disc capacitor but is more than likely a MOV suppressor - did your circuit breaker trip? depending where the surge came from the board may still be good, try clipping the MOV out of the circuit and resetting the breaker. They are only a dollar and if proved can be replaced later.

The control board must see that pressure switch initially open before starting the sequence then closed after the fan starts - this is so you can't trick it with a jumper wire. After seeing the board I doubt its bad.

And as DM said make sure your lines are clear on the switch.


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## klas (Apr 6, 2009)

Thank you for your suggestions!

The control board was "burnt" as you see on the picture for 4 years. It was recommended to get it replaced, but I never bothered with it as everything was working fine until recently. 

Repair man did some tests, like blowing into a tube to check if it "clicks" and plugging blower wire directly to a switch to check if the fan is working.

The result: Blower didn't "click", but the fan was working.

So his assumption that the control board gone bad finally along with a pressure switch, but since he wasn't sure I did not want to pay the price only to find later something else has gone bad. So, I will try to replace control board first before I replace pressure switch. 

I am bit hesitant to clip something of the board though. I would rather try another board.

Luckily, the weather finally starting to get warmer, so I can go by without furnace for a while.


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## qbert (Mar 23, 2009)

Not the way to test pressure switches


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## beenthere (Oct 11, 2008)

Apparently, the tech can't afford a manometer.


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## klas (Apr 6, 2009)

So my current concerns are... Is Control board simply plug & play? and... I heard someone mentioned that pressure switch might need cleaning. Will it help?


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## hvaclover (Oct 2, 2008)

hychesee said:


> Very strange for both the draft inducer pressure switch to go bad and the control board to short out. In the board picture it looks like a disc capacitor but is more than likely a MOV suppressor - did your circuit breaker trip? depending where the surge came from the board may still be good, try clipping the MOV out of the circuit and resetting the breaker. They are only a dollar and if proved can be replaced later.
> 
> The control board must see that pressure switch initially open before starting the sequence then closed after the fan starts - this is so you can't trick it with a jumper wire. After seeing the board I doubt its bad.
> 
> And as DM said make sure your lines are clear on the switch.


You replace any electronics on that board and you will void any homeowners policy you own. 

The boards are safety lab certified as a whole component. Any damage occurring to home traceable to furnace would not be covered.

If the boards were meant to be repaired outside lab conditions there would be a market for recycled boards. Most tech have the know how to repair a board but have the good sense not to.


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## hychesee (Oct 31, 2008)

that's hilarious, thanks - grins back at ya


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## kenmac (Feb 26, 2009)

Is the red light ( bottom rt in the pic) blinking, showing any codes ?


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## klas (Apr 6, 2009)

yes, it's blinking slowly on/off. Where can I see blinking interpretation?


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## kenmac (Feb 26, 2009)

Probably just indicating power to the unit. Usually count # of blinks & look on the back of the blower door for the code


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## klas (Apr 6, 2009)

Normal. No call for heat. 

Just a note that there is a manual switch to run just the fan for fresh air intake and if connected directly to switch fan works, but when connected through control board as normal it will not work. Does this suggest that control board is actually faulty?


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## kenmac (Feb 26, 2009)

If you have a V M you could check for 110 v at the red terminal on the board on a call for heat..Red from V M to red wire terminal.. black lead from V M to ground or white.. If you have 110 v the fan should run


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## hvaclover (Oct 2, 2008)

hychesee said:


> that's hilarious, thanks - grins back at ya


Contact the mfg of any HVAC brand. They'll confirm what I told you.

Controls are not rebuilt for a darn good reason. When a new furnace model is safety certified it is with the components that the mfg hast designed in to it.

Any field alterations would be considered a deviation (that means repairing a board or any other part of the safety or ignition system) from the original design and puts the liability squarely on the shoulder of the offending individual.

There was a guy around here who was repairing Bryant blower boards some years ago for local wholesaler. UTS shut 'em down hard. And rightfully so.

The solid state components were generic and not the same quality the OEM put into to the board. There were a few cases of gas valves not closing on the end of a cycle.
I ran those calls and they were the repaired boards I mentioned.


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## kenmac (Feb 26, 2009)

hvaclover said:


> Contact the mfg of any HVAC brand. They'll confirm what I told you.
> 
> Controls are not rebuilt for a darn good reason. When a new furnace model is safety certified it is with the components that the mfg hast designed in to it.
> 
> ...


 


I agree... Wouldn't buy parts off E-Bay either


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## hvaclover (Oct 2, 2008)

kenmac said:


> I agree... Wouldn't buy parts off E-Bay either


Glad we agree. Ebay is not the place to buy a part. Whose gonna back up the warranty?


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## yuri (Nov 29, 2008)

The other issue no one seems to understand or care about is that a circuit board is a critical safety device. If you mess it up and the flame sensor/flame failure part of it quits you can fill up the furnace/house with gas and voila, first person to turn on a light switch blows up the house. Nothing against some DIY repairs but fixing circuit boards is verboten.


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## klas (Apr 6, 2009)

Update, got the new control board, it was a breeze to replace. Turned the system on and the fan started just fine. Now, another problem is with the burner, the gas burner turns on for a few seconds and then shuts off. Is this a symptom of a bad pressure switch?


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## kenmac (Feb 26, 2009)

sounds like flame sensor.. Clean it or make sure it has good connection on the new board


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## klas (Apr 6, 2009)

kenmac said:


> sounds like flame sensor.. Clean it or make sure it has good connection on the new board


can you tell me where is it located?


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## kenmac (Feb 26, 2009)

it will be a steel rod that the burner flame burns against as the flame shoots into the chamber.. It's around the burner


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## hvaclover (Oct 2, 2008)

Right here


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## klas (Apr 6, 2009)

Got it! Thanks! Cleaning it now


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## klas (Apr 6, 2009)

Cleaned with sand paper... still no go... system cycles on/off. Anything else?


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## klas (Apr 6, 2009)

btw, check out the back of my old control board


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## klas (Apr 6, 2009)

cleaned it a little more... no change 

should i order a pressure switch now?


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## klas (Apr 6, 2009)

I checked the code with 5 blinks... "Flame sensed when no flame should be present" Maybe that will give some ideas?


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## beenthere (Oct 11, 2008)

Probably a polarity problem.

Check your wiring, and your grounds.


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## kenmac (Feb 26, 2009)

It doesn't sound like ps.. You can jump it out just for testing.. Where did you get the board ?? operation is controlled by the board


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## klas (Apr 6, 2009)

Polarity shouldn't be an issue. I plugged in everything the same way as it was before. 

kenmac >Can you be more specific about "jumping out"?


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## kenmac (Feb 26, 2009)

The ps switch will have 2 wires attached. connect them together.. WARNING.... This is a safety & shouldn' t be left jumped out.. Only for testing


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## kenmac (Feb 26, 2009)

klas said:


> I checked the code with 5 blinks... "Flame sensed when no flame should be present" Maybe that will give some ideas?


 

Only idea this gives me is the board / sensor says there is a flame there when no flame should be


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## beenthere (Oct 11, 2008)

klas said:


> Polarity shouldn't be an issue. I plugged in everything the same way as it was before.


Sometimes new boards are a bit more sensitive then the ol board.

And a resistive ground connection will cause it.


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## klas (Apr 6, 2009)

well, put a new pressure switch just to test it out and that did not resolve the issue. I even took the front fan apart just to check it out. I am really pulling my hair on this.


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## klas (Apr 6, 2009)

wow, i just noticed 6 blinks. it's not 5 as I initially thought. 6 blinks related to polarity issue. Can someone tell me how do I troubleshoot this issue?


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## beenthere (Oct 11, 2008)

I could swear I said a polarity problem earlier.

Recheck your electrical connections. 
Recheck your ground connections.

Has any electrical work been done in the house recetly before your furnace stopped working.


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## klas (Apr 6, 2009)

well it's odd. on a video it showed 6 blinks, but i just checked again and it actually blinked 5 times. Nevermind, false alarm about the blinks... 

btw, you gave me an idea about connections... technician was unplugging things and plugging them around. Could it be that he plugged in something to the wrong place? Can you tell from the picture if connections are correct?


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## klas (Apr 6, 2009)

Unfortunately, I did not take a picture prior to technician


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## beenthere (Oct 11, 2008)

Its acting like a dirty flame sensor, or the pressure switch opening during the burner run time.

A poor ground can cause problems with flame sensing.
A loaded ground can cause a false flame sense problem.
Check for voltage between neutral and ground.

Got some rust in it also. Time to check the heat exchanger for cracks and holes.


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## klas (Apr 6, 2009)

I might try replacing flame sensor as well.


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## hvaclover (Oct 2, 2008)

Try checking if the pressure tap off the inducer is plugged. Could be causing the press switch to fluctuate.


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## klas (Apr 6, 2009)

don't see any pressure tap


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## klas (Apr 6, 2009)

Checked all wiring, seems ok.

Reading through manual noticed that description for 5 blinks is as follows: Flame sensed with gas valve off. 

Description in the back panel for 5 blinks: Flame sensed when no flame should be present


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## beenthere (Oct 11, 2008)

What was the voltage reading between neutral and ground.
What was the voltage reading between hot and ground.
What was the voltage reading between hot and neutral.

Did you check for a shot in the flame sensor wiring.
What was the ohm reading.


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## kenmac (Feb 26, 2009)

Looks like flame sensing issue or ps switch loosing vaccum. Did you jump out the ps or just replace it ?


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## Grampa Bud (Apr 6, 2009)

Hi Guys, I've got one more for you. I've worked on draft induced boilers and waterheaters for fifteen years now and have run across several in both catagories where for what ever reason dirt, dust, grit has been sucked thru the blower and has coated the inside of the housing and all the little vanes on the blower wheel. The complaint is the same as yours. The fix I have run across most often is to simply clean out the blower squirting windex thru the draft into the blower or in some cases taking the blower apart and cleaning everything with a damp (not oily) cloth. There is so little press/vac needed to make the switch work I could never get a good reading on our manometer, but after cleaning the switch would activate the ignition circuit and we had liftoff again.


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## klas (Apr 6, 2009)

got the right one


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## kenmac (Feb 26, 2009)

I think you were advised not to buy used parts or parts off e-bay


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## Yoyizit (Jul 11, 2008)

You may want to look for a root cause that is shortening the life of these components, so the new ones don't smoke.

Since you can have an almost 100% certain repair for $600, you should decide at what point you will stop throwing money and time and aggravation at an uncertain repair (the Slippery Slope). $300 might be a good stopping point.


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## klas (Apr 6, 2009)

i bought it off ebay before I was "advised", in any case I ordered a new one just so I can eliminate this issue as possibility. 

So far I've spent already $50 on a used control board, $70 pressure switch, $100 diagnostics, $140 new control board. If the new control board doesn't resolve issue I will have to call for technician... another $100

the "100% sure $600 repair" was already done for a lot less. Technician said it was a control board an pressure switch. Obviously, he was wrong about pressure switch, as the new one didn't resolve the issue


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## Yoyizit (Jul 11, 2008)

hvaclover said:


> Any field alterations would be considered a deviation (that means repairing a board or any other part of the safety or ignition system) from the original design and puts the liability squarely on the shoulder of the offending individual.
> 
> There was a guy around here who was repairing Bryant blower boards some years ago for local wholesaler. UTS shut 'em down hard. And rightfully so.


Who is UTS? 
On what grounds did they prevent this aftermarket repair business? Was the repairer insured?
How did he get necessary [proprietary?] schematics, etc.?
Thanks.


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## hvaclover (Oct 2, 2008)

I am officialy calling this guy a BSer troll...


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## hvaclover (Oct 2, 2008)

Fifty four posts and dodging questions says he buying used parts.
He's jerking your chains.


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## hvaclover (Oct 2, 2008)

Yoyizit said:


> Who is UTS?
> On what grounds did they prevent this aftermarket repair business? Was the repairer insured?
> How did he get necessary [proprietary?] schematics, etc.?
> Thanks.



United Technologies. They own Carrier and Bryant. The grounds were the alteration of a board that was patently against the law. If one of those boards were to cause a death the OEM would be held liable as would the repairer. 

The repairer would not be able to get insurance as what he was doing was illegal.

All he did was bench test the board and the electronics that made it up. He replace the bad ones. But their quality was substandard and caused problems


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## Yoyizit (Jul 11, 2008)

hvaclover said:


> Fifty four posts and dodging questions says he buying used parts.
> He's jerking your chains.


You mean the OP is playing this game?

"Why Don't You/Yes But
The first such game theorized was Why don't you/Yes, but in which one player (White) would pose a problem as if seeking help, and the other player(s) (Black) would offer solutions (the "Why don't you?" suggestion). 

White would point out a flaw in every Black player's solution (the "Yes, but" response), until they all gave up in frustration." 

If so, he's not a "hard player." After all, he did spend money seeking a solution.


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## klas (Apr 6, 2009)

hvaclover said:


> I am officialy calling this guy a BSer troll...


that was really uncalled for. I was looking for help. Thanks for your time!

but, just to make you happy, I just came back from the store with a brand new board because I couldn't wait any longer ordering parts online. I put it on and that did NOT resolve my issue. Thank you for suggesting to waste more money on something I didn't need. Used or not, that's was not an issue, obviously, but I see it how easy it is to blame a product that was used.


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## beenthere (Oct 11, 2008)

klas said:


> that was really uncalled for. I was looking for help. Thanks for your time!
> 
> but, just to make you happy, I just came back from the store with a brand new board because I couldn't wait any longer ordering parts online. I put it on and that did NOT resolve my issue. Thank you for suggesting to waste more money on something I didn't need. Used or not, that's was not an issue, obviously, but I see it how easy it is to blame a product that was used.





> What was the voltage reading between neutral and ground.
> What was the voltage reading between hot and ground.
> What was the voltage reading between hot and neutral.
> 
> ...


Did you check any of the above.


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## klas (Apr 6, 2009)

beenthere said:


> Did you check any of the above.


I am not in expert in how to check for these exactly, but I am trying to learn. I checked that all the wires are properly connected. That's as far as I got.


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## beenthere (Oct 11, 2008)

Without using a multi meter to check those things.
About all you can do is guess which part, and keep changing parts until you get the right one.

And if it happens to be an electrical problemoutside of the furnace.
You'll of rebuilt your furnace. And still not have a working furnace.

I would still try Ken's suggestion.

Of starting the furnace. then jumping the PS wires together, and see if it stays running while the wires are jumped together.

Ok, I'd use my meter to see, but thats beside the point.


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## Yoyizit (Jul 11, 2008)

Yeah, cut your losses. 
The money you've already paid was the tuition for the lessons you've learned. Viewed in that way, you might have gotten a bargain.


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## klas (Apr 6, 2009)

I am not regretting money spent so far, I did learn quite a bit, where just a week ago I was afraid to touch this thing. Now I even able to take it apart partially. Thanks for all your help so far! 

Next steps is to purchase and learn to use multimeter


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## Yoyizit (Jul 11, 2008)

klas said:


> I am not regretting money spent so far, I did learn quite a bit, where just a week ago I was afraid to touch this thing. Now I even able to take it apart partially. Thanks for all your help so far!
> 
> Next steps is to purchase and learn to use multimeter


http://en.wikipedia.org/wiki/Troubleshooting
http://en.wikipedia.org/wiki/Category:Electrical_safety
http://en.wikipedia.org/wiki/Correlation_does_not_imply_causation
http://en.wikipedia.org/wiki/Furnace
http://en.wikipedia.org/wiki/Electronic_test_equipment

If you plan on keeping the furnace, see if the manuf. will sell you a Factory Service Manual. I got mine for free from Bryant. You really need Theory of Operation, logic diagrams, sequences, the whole bit. . .
Watch out for sharp sheet metal edges.


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## klas (Apr 6, 2009)

Yoyizit said:


> http://en.wikipedia.org/wiki/Troubleshooting
> http://en.wikipedia.org/wiki/Category:Electrical_safety
> http://en.wikipedia.org/wiki/Correlation_does_not_imply_causation
> http://en.wikipedia.org/wiki/Furnace
> ...


Thanks for links. I've actually have the manual that came with the furnace and I was trying to study the diagram when I was checking if the connections are proper. At first glance it looked more complicated then a programmer's code, but some things made sense.




Yoyizit said:


> Watch out for sharp sheet metal edges.


Now you tell me.  I've got a few scratches already, including this itchy feeling from fiberglass.


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## hvaclover (Oct 2, 2008)

Well they always accuse the pros for throwing good money after bad.

I stand by what I said. Make sense to you a guys gonna wait eight days of coaching with no heat?

He only comes out and says he does not understand a meter only after he's been called out...is that honesty from the OP or is it just another way to prolong this thread for his personal amusement?

I calls em as I sees em.


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## klas (Apr 6, 2009)

edit.


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## klas (Apr 6, 2009)

hvaclover said:


> Well they always accuse the pros for throwing good money after bad.
> 
> I stand by what I said. Make sense to you a guys gonna wait eight days of coaching with no heat?
> 
> ...


I am sorry I have trouble understanding your language, but I sense that you are accusing me of something.

Just fyi, I am fine without having a working furnace, I am not in a rush to fix it. I only need to heat 1400 sq ft and I have 3 electric heaters as well as gas fireplace as a backup. Not to mention the weather has been pretty good.

I never claimed I was a pro, hence my subject and first post that points that I am new at this. The "pro" that came to diagnose my problem wanted $600 for something that I could done myself replace a control board and a pressure switch that wasn't even bad to begin with. With some helpful advices here I was able to get more comfortable with troubleshooting the issue and money spent is worth it even if it didn't completely resolved the issue. 

Who is a troll here? Sounds to me that person who attacks others seeking for some help. Don't want to help? Please stay away from this thread. Your negative comments are not helpful. Thank you!


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## hvaclover (Oct 2, 2008)

klas said:


> I am sorry I have trouble understanding your language, but I sense that you are accusing me of something.
> 
> Just fyi, I am fine without having a working furnace, I am not in a rush to fix it. I only need to heat 1400 sq ft and I have 3 electric heaters as well as gas fireplace as a backup. Not to mention the weather has been pretty good.
> 
> ...


Your entitled to your opinion just as I am mine. There are certain markers that reveal a posters who is in it just for kicks. Your posts have tripped almost everyone.

If the other gents wish to expend the energy to chase your elusive problem than I am not in a position to object. 

By the way there is a press tap on the the collector box. Did you check to make sure that is not partially plugged.?


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## kenmac (Feb 26, 2009)

beenthere said:


> I would still try Ken's suggestion.
> 
> Of starting the furnace. then jumping the PS wires together, and see if it stays running while the wires are jumped together.
> 
> Ok, I'd use my meter to see, but thats beside the point.


 

Been,I would also use a meter.


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## klas (Apr 6, 2009)

thanks guys! I am putting this on hold I until I am back from vacation... maybe when I am back I'll get some fresh ideas or it would magically start working again...


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## hychesee (Oct 31, 2008)

Too bad this thread took the route the Somalian pirates only take, the high and mighty like to see their opinion in print for no other reason but to be a loud mouth "god save the queen" bully ... <period>. This altruist crap runs like diarrhea. Have fun on your vacation and when you get back go ask for advice on a real help forum and not one where they rub nuts.


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## kenmac (Feb 26, 2009)

Who would you be speaking to or about ??. I think everyone here has tried to help this guy


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## hvaclover (Oct 2, 2008)

kenmac said:


> Who would you be speaking to or about ??. I think everyone here has tried to help this guy


It's a group of pros (or possible just one using many names) who just want to give DIY site grief.


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## hvaclover (Oct 2, 2008)

hychesee said:


> Too bad this thread took the route the Somalian pirates only take, the high and mighty like to see their opinion in print for no other reason but to be a loud mouth "god save the queen" bully ... <period>. This altruist crap runs like diarrhea. Have fun on your vacation and when you get back go ask for advice on a real help forum and not one where they rub nuts.


Geez ...take it easy you'll have a coronary....


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## Cgdishong (Oct 19, 2015)

*Furnace Repair*

late 80s high efficiency natural gas furnace, when switched on the pilot comes on , burners ignite and then the burners go out but pilot stays on


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## Grampa Bud (Apr 6, 2009)

Turn your thermostat up 10 or 20 degrees from where it is. If the pilot lights and stays on and the main burners light, even for a minute, the furnace is working, but it doesn't have any call for heat. If this doesn't work is your thermostat powered from the furnace wiring or does it have a 'AA' battery inside it ? Basically on a call for heat your stat only gives your furnace a closure like a light switch so you can try crossing the stat "heat" leads to see if the furnace responds with heat.

Gramp Bud


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