Furnace tale of - Water damage from condensation

Problems related to residential installations.

Furnace tale of - Water damage from condensation

Postby swruch » Sat Nov 05, 2011 2:18 pm

First time poster here - this seems like a helpful community and I wanted
to get your opinion on a problem we're having with our furnace.

I had an Amana CCA36FDC installed about 8 years ago, along with a new
AC system as well. Last year towards the end of the heating season the
ignitor went bad twice in about 2 months. The 2nd time it was replaced
the technician noticed that water had gotten inside as the jets had some
rust on them. The hose from the humidifier had become clogged earlier
that year and some water had leaked down the side of the furnace - so we
assumed that was what caused the rust.

This year I went turn on the heat for the first time and it wouldn't light.
Only the jets nearest the ignitor would burn and thus the thing would
shut down after a few seconds. The technician notices that there's more
rust and says there's condensation leaking back down the flue. I never
actually saw it happening but after 2 weeks of checking several times a
day, I managed to see some water dripping back one morning after a cold
night (as the chimney warmed up in the sun, I surmised). The proposed
solution is a new chimney liner with the theory that the existing one has
buckled or has otherwise become damaged in such a way that condensation
will form on occasion and will continue to drip into my furnace unless it
is replaced. I have had the chimney exterior inspected to confirm that
there isn't any deterioration or another explanation for water getting in.

So we have water damage inside the furnace. The tech got it working
again by cleaning the rust off the jets but a new issue has cropped up.
It will work for a while and then at some point it will refuse to turn on.
The control board LED blinks eight times, which the tech says is the code
for "bad ignitor ground" (my paraphrasing). He was going to replace the
ignitor again, but didn't have one. We left it turned off last night (the
power to the furnace itself was turned off) and this morning I turned it
back on just to see if it would come on - and it did. It ran from about 8am
until 1pm or so and then it stopped with the LED blinking 8 times again.

The code seems to be incorrect as the ignitor is working. Could it mean
something else - or perhaps has the control panel or some other part
been damaged such that the wrong code is being generated?

Any opinions on the water issue and the proposed solution would also
be greatly appreciated.
swruch
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- Furnace tale of - Water damage from condensation

Postby juster » Sun Nov 06, 2011 11:27 am

The code your furnace is giving you, could be the ignitor. If you are not getting a proper ground it may be intermittent. You should have the tech trouble shoot to confirm. Intermittence is a tough one, it is always the case that the problem does not show up when the tech is there. May need to cycle many times.

Regarding the chimney, Did the cap get blown off? if you have confirmed that you are not getting water from other sources (rain), the insulation value has deteriorated for some reason. If your chimney is brick or stone you may need a new liner. If not get your tech to test. May need to wait until the out side air temp is cool enough in order for the tech to spot the problem. Good job in gathering the info on when the condition occurs. Continue to monitor any conditional info and record. The more info you can give the tech, the faster he can trouble shoot.
juster
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- Furnace tale of - Water damage from condensation

Postby swruch » Sun Nov 06, 2011 1:03 pm

juster -
> The code your furnace is giving you, could be the ignitor. If you are not
> getting a proper ground it may be intermittent. You should have the tech
> trouble shoot to confirm. Intermittence is a tough one, it is always the
> case that the problem does not show up when the tech is there. May need to
> cycle many times.

Thanks - that will be the next step then. Once it starts happening, if I
shut the power to the furnace off for an hour or so, it will work again
for a while. Very strange.

> Regarding the chimney, Did the cap get blown off? if you have confirmed
> that you are not getting water from other sources (rain), the insulation
> value has deteriorated for some reason. If your chimney is brick or stone
> you may need a new liner. If not get your tech to test. May need to wait
> until the out side air temp is cool enough in order for the tech to spot
> the problem. Good job in gathering the info on when the condition occurs.
> Continue to monitor any conditional info and record. The more info you can
> give the tech, the faster he can trouble shoot.

I inspected the chimney myself - saw nothing wrong. The cap still looks brand
new. Had a chimney guy look as well - he could see nothing wrong outside.
The last 2 times it's leaked some water there was no precipitation. The last
time there was rain / snow (we just had a freak early snow here in NJ the other
week) - there was no leaking.

The chimney is brick and the chimney guy said there is some spalling and the
chimney would have to be resurfaced eventually, but since there is a terracotta
liner inside the chimney and then the metal liner sits inside that, it's extremely
unlikely there's any water getting in from outside due to leakage.

The chimney does sit entirely outside the house and the fireplace chimney is
adjoined (we have one of those fireplaces that's just for entertainment - it
only warms the room it sits in). We don't use the fireplace that often, but
could it's proximity to the furnace chimney have caused the liner to warp? Or
given the fact that it sits completely outside the house, could that make it
more susceptible to condensation? I have this fear that there's something
inherently wrong with this set-up that's going to cause this to happen again
someday. Chimney liners aren't cheap. We have to get stainless now too
since the building code has changed since 8 years ago and our hot water
heater uses the same chimney.
swruch
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- Furnace tale of - Water damage from condensation

Postby juster » Tue Nov 08, 2011 9:52 am

With the chimney outside your house, yes this could make it susceptible to flue gases cooling, especially if it has started to crack in some areas. I see you have already noticed that at some times your do or do not have the condensation problem. Hard to say what the problem is at this time. Do you have a natural incoming fresh air duct close to your furnace? There should be one. This is for combustion. You should be getting a draft in the chimney at all times.
Sorry I can't be of more help.
juster
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Posts: 123
Joined: Tue Mar 30, 2010 7:40 am


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