HVAC Water Leakage and subsequent malfunction


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Old 06-03-08, 06:18 PM
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HVAC Water Leakage and subsequent malfunction

I have 8 years old goodmap GMP-100 HVAC system. I had the blower replaced last winter. When I started the AC few weeks back, I noticed significant water leakage. I cut opened the condensate pipe and found blockage in the trap. I poured water into the line just to make sure there is no blockage in the remaining line that is still attached to the unit. The water had leaked for at least a week, however the AC was functioning.

However now, after cutting the line, I find that both the AC and the heater is not working. If I keep the unit off for several hours, AC start functioning, however shuts off after about 15 minutes of operation. Also the water does not come out of the condensate line, it starts dripping out of the the plenum. At this time, If I switch off the AC and start it again, it won't start at all (neither the outside unit, nor the blower). Again if I keep the unit off for several hours - I can repeat the same cycle.

The heater has stopped working as well. It shows no activity at all - no flames, no gas blowing and heating element doesn't get hot. The heater does not work even when the unit id off for a long time.

The blower is working fine and I can run it in the fan-on mode. I am wondering if the water leakage has caused some damaged the circuit board or the capacitor or any other part of the unit.
 
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Old 06-05-08, 04:56 AM
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Pls confirm, is the full m/n for this furnace:
GMPE100-4 ?
GMPE100-4A?
or is it indeed GMP...?

Yes, it is likely that the board may have been compromised.

Post some pics of the furnace's controls section if you could, as well as the water damaged area.
 
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Old 06-05-08, 04:07 PM
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Thanks for your reply. The model no on the unit is "GMP100-4 REV B" Here is the photo of the control board

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The water has dried now and there is no visible sign of water damage. I was wondering if it is safe to start the unit and note the control-light blinks?
 
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Old 06-05-08, 06:42 PM
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I can see some water marks running down past the transformer and go behind the board. But indeed, no obvious signs of water damage.

Yes, you may start the unit. Maybe you'll get lucky and it will get going. Let us know what the blinking code reads.
 
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Old 06-06-08, 06:18 AM
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Thanks pflor !

I started the unit in heat mode and noticed two blinks - meaning the pressure is stuck closed. Is it possible to get the pressure switch damaged because of leaking water?
 
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Old 06-06-08, 06:21 AM
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Yes it is.

How about running the system in the cooling mode. Does it run?
 
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Old 06-06-08, 10:35 AM
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In the cooling mode, it works fine for 15 minutes and then the blowers stops. There is no blinking light. If I switch off and on again, the blower doesn't start. If I leave it off for several hours, again it works for 15 minute.

I called the technician today and he diagnosed that the board is bad and needs to be replaced. That is quite expensive - 225$. Does that sound reasonable.
 
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Old 06-06-08, 10:52 AM
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It is very plausible that the board is malfunctioning (behaving erratically) as a result of the water leak. Electronics and water are not good bed-fellas.

$225 for a board is not unreasonable.

You should go ahead and have it replaced.
 
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Old 06-06-08, 06:57 PM
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Thanks for your advice. The board is replaced. Heater and AC are both functioning. However after 30 minutes of AC operation, the water is leaking again and not coming out from the condensate pipe. The technician is saying that the pan may be cracked and may have to replace pan+coil assembly. This may be well over 1000$ I really don't know why coil should be replaced.
 
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Old 06-06-08, 07:53 PM
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The coil comes attached to the pan, this is not something that could be separated...in other words, I do not know of any place where you would buy only the pan, or only the coil...and if it is cracked (and good chances are since there's dripping once more), replacement is the only alternative.

Maybe is something else (if you're on luck), but there's no way of telling unless the coil is first removed to be inspected. That is a significant amount of work, so it won't be cheap.
 
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Old 06-06-08, 09:27 PM
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For the heck of it, can you take pics (and post) that show the coil and the PVC trap attached to it (at various angles and distances)? I'm trying to see if perhaps there's a problem with the trap and the condensate is not draining b/c of it.
 
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Old 06-07-08, 06:13 AM
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Thanks for your continued interest. I am attaching the photo of plenum where the drain is attached. As you see, the coil and pan is not easily accessible or visible. The technician had to use a scope to see the coil and pan and couldn't see any damage. However the drain assembly was opened completely and the new one is in place , so no blockage there.

Howevere I can see that for this unit, pan ($200) and coil ($900) are sold separately at expertappliance.com. So it should be possible to replace the pan. The control board is also available for $130 (I paid $225 to the technician)

Now I remember the plastic burning smell in the house, when my blower had stopped working in last winter. I am wondering if it was the smell of melting drain pan because of excessive heat built up.

 
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Old 06-07-08, 07:04 AM
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Originally Posted by money2008
I can see that for this unit, pan ($200) and coil ($900) are sold separately at expertappliance.com. So it should be possible to replace the pan. The control board is also available for $130 (I paid $225 to the technician)
Make sure to check with the Tech that the pan you've seen is the right one for you and that they are o.k. with you buying it and they installing it, else you may find yourself in the situation of this company (and the tech that works for it) declining do the pan replacement job b/c of warranty issues. Put yourself in their shoes, it will be that company's name and reputation to have to honor a job for a part that you can't guarantee will work as intended...it may very well be a lemon of a part, and who knows, you may have other issues there besides the pan.

On the board price matter, I also hope you realize that any service provider has to mark up their work. You call professionals, they have to pay salaries, gas, overhead...you name it.

In the area where I live, I know of neighbors that have had board replacements, they have gotten charged in excess of $350 for it (more for a weekend job), and I know for fact that the boards for our furnaces (homes in my development) go for about $85. The point is, as a professional, you charge what you think your services are worth, and lack of competition exacerbates this. Heck, lawyers could charge you over $200 an hour to charm you.


Originally Posted by money2008
Now I remember the plastic burning smell in the house, when my blower had stopped working in last winter. I am wondering if it was the smell of melting drain pan because of excessive heat built up.
So this problem seems to have been going on for quite some time, huh? Beware, depending on where the leak has been draining, it may have already compromised the furnace's heat exchanger
 
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Old 06-07-08, 09:55 AM
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Well, my intension for quoting the price of parts was not to buy them myself. I wanted to verify why the technician said - the two things are together and you cannot buy pan without getting a new coil.

I really want to know if I need to buy a new coil in order to replace a damaged pan. Especially when the coil is 10 times expensive than the pan and both are available as individual parts from goodman. Is there any technical reason why coild should be replaced ?
 
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Old 06-07-08, 12:24 PM
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If Goodman sells the pan+coil as a unit and not separately, and if you were to decide to replace the defective component with a new Goodman component, there's the reason.

But if you had the license, tools, testers & know-how, by all means, try the pan. The thing is, tech work of any nature, regrettably, does not come cheap. And to do the type of work your unit needs, there's a significant amount of work involved.

I know very litttle about cars, and when one of mine break, I know I could expect an invoice of several hundred dollars or more, depending on what the mechanic says needs to be done. I don't like it, but what's the alternative?

That store where you found the items, is not cheap. A pan should be much cheaper, and I was expecting a coil with the pan to have a price lower than the $900 you mention. Does the quote of $1,000 the tech gave you for the coil+pan replacement include labor? If so, it's cheaper than the place where you got your quote.
 
 

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