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-   -   First time furnace repair. Any advice? (http://www.diychatroom.com/f17/first-time-furnace-repair-any-advice-41923/)

klas 04-06-2009 01:35 PM

First time furnace repair. Any advice?
 
Issue was resolved

DangerMouse 04-06-2009 01:51 PM

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

klas 04-06-2009 02:02 PM

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-f...QQcmdZViewItem

yuri 04-06-2009 02:31 PM

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.

hychesee 04-06-2009 02:39 PM

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.

klas 04-06-2009 02:52 PM

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.

qbert 04-06-2009 04:01 PM

Not the way to test pressure switches

beenthere 04-06-2009 04:03 PM

Apparently, the tech can't afford a manometer.

klas 04-06-2009 05:44 PM

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?

hvaclover 04-06-2009 06:36 PM

Quote:

Originally Posted by hychesee (Post 255882)
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.

hychesee 04-06-2009 06:44 PM

that's hilarious, thanks - grins back at ya :)

kenmac 04-06-2009 07:49 PM

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

klas 04-06-2009 09:11 PM

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

kenmac 04-06-2009 09:25 PM

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

klas 04-06-2009 09:36 PM

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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