# Furnace condensate drain/trap issue



## yuri

Cut the trap out and soak the whole thing in a bucket of strong bleach/Javex for an hour and then flush it. I would cut the horz pipe after the trap, then go to HDepot and get some large clear hose to cobble it back together.


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## SteveC

So just having some additional buildup on the inside walls of the trap can cause these symptoms? Even though I appear to get good flow through the trap by forcing tap water through it? Interesting.

I'll probably just pick up a 3/4" PVC coupling and cut the horizontal drain line about where the tie wrap is on it right now, then glue it back together.

< edit to add: >
So Javex is just regular bleach? Just like Clorox? I thought at first it was something special until I did a search.


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## marchvac

Does the drain pipe go down to deep into the condensate pump. You could try putting a bucket there to see what happens. The drain pipe should be above the water level. The drain pipe should only be into the pump about 1/8 ".


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## SteveC

marchvac said:


> Does the drain pipe go down to deep into the condensate pump. You could try putting a bucket there to see what happens. The drain pipe should be above the water level. The drain pipe should only be into the pump about 1/8 ".


I was wondering that same thing earlier today and I have already shortened the pipe some. It's definitely still quite a bit more than 1/8" into the pump reservoir though (more like 3/8" to 1/2"), but to test the idea I finagled the pipe out of the pump completely and let it drain onto a towel while the furnace was running, and even so there was water backed up into the hose upstream of the trap. That test, along with adding a weep hole in the top of the PVC drain pipe (see last photo in the original post), kind of eliminated that as a potential issue in my mind. I'll go ahead and shorten the drain pipe some more just to be sure that it is above the water level in the pump, but I don't _think_ the problem lies there.

Thanks for the suggestion though.


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## yuri

The thin black hose vents the trap and is probably a critical sized opening inside the port at the trap and the ventor fan. Siphoning is very tricky and it does not take much to slow it down. May have to take a paper clip or small bit and ream out the port on the ventor fan, can get a sulphur buildup there. Getting more calls with algae built up inside traps as it does that during the Summer when there is no flow. Did you check the intake part of the concentric? If you can carefully pull the hood off check inside for spider webs. If it wont easily come apart stick your fingers in there and use a bottle brush.


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## SteveC

yuri said:


> The thin black hose vents the trap and is probably a critical sized opening inside the port at the trap and the ventor fan. Siphoning is very tricky and it does not take much to slow it down. May have to take a paper clip or small bit and ream out the port on the ventor fan, can get a sulphur buildup there. Getting more calls with algae built up inside traps as it does that during the Summer when there is no flow. Did you check the intake part of the concentric? If you can carefully pull the hood off check inside for spider webs. If it wont easily come apart stick your fingers in there and use a bottle brush.


When you say "...ream out the port on the ventor fan..." I presume you're talking about where the small hose attaches to the fan plenum (see photo)? I'll try cleaning that out.









As far as the concentric, I did not try to take it apart. I felt around on the inlet side as best I could, and removed a couple of small old leaves, but didn't detect any major blockage. I'll try taking it apart (carefully) and check that when I get back into town on Tuesday.

Thanks again.

< edit to add: >
"...algea inside the trap..." explains the bleach. Thanks.


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## PeteMc

*I have the same exact problem*

Did you ever find the problem.
I've been dealing with this problem for years. 
It's been once a month that I've had to restart the thing.

Did you have to buy a new trap?

Looking at the pictures of your furnace, I thought I was looking at my own furnace.


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## hvaclover

yuri said:


> The thin black hose vents the trap and is probably a critical sized opening inside the port at the trap and the ventor fan. Siphoning is very tricky and it does not take much to slow it down. May have to take a paper clip or small bit and ream out the port on the ventor fan, can get a sulphur buildup there. Getting more calls with algae built up inside traps as it does that during the Summer when there is no flow. Did you check the intake part of the concentric? If you can carefully pull the hood off check inside for spider webs. If it wont easily come apart stick your fingers in there and use a bottle brush.


That plastic is made to resist build up so it can be washed out easily.

Did you notice the tube up hill rise over the blower door switch? That could be your only problem.


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## hvaclover

Push come to shove you could eliminate that plastic trap and buy one or fashion a new trap with PVC elbows.

I am dealer for the brand of furnace you have.


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## PeteMc

Where/what is the blower door switch?


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## mastertech

If Im not mistaken isnt that plug with the red clamp supposed to be open so the trap can vent properly.The only thing that can go wrong with a p trap is not installed correctly with the vent and or it getting plugged up.I think your not letting it vent properly after the trap does its job.It fills up than it cant drain into the sump.


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## pmahar

I had the same issue with my furnace. All that was needed was $1 in shims. The furnace needed to be pitched just a little towards the drain hoses. When the furnace shuts off and the suction stops the water drains. I couldn't believe it was that simple....


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## Master of Cold

pmahar said:


> I had the same issue with my furnace. All that was needed was $1 in shims. The furnace needed to be pitched just a little towards the drain hoses. When the furnace shuts off and the suction stops the water drains. I couldn't believe it was that simple....


Its not.....


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## Carlos2sun

PeteMc said:


> Did you ever find the problem.
> I've been dealing with this problem for years.
> It's been once a month that I've had to restart the thing.
> 
> Did you have to buy a new trap?
> 
> Looking at the pictures of your furnace, I thought I was looking at my own furnace.




Totally agreed!Maybe you just need a new trap!


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## raylo32

Sure looks like that rise in the tubing, as noted by HVAClover, could be the problem. There is not a lot of vertical difference to keep the water moving. Flatten that out and see what happens.


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## pmahar

Master of Cold said:


> Its not.....


I guess it might not be simple for everyone to pitch their furnace with shims but it was simple for me. I used a crow bar and a couple pieces of wood to slightly lift the furnace and then slipped the shims underneath. Once I did that the condensate drained out of my furnace through the trap and the furnace started heating again. I got the idea from a neighbor who has many years experience in the HVAC business.:thumbsup:


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## rick31797

*furnace*

I wonder what the fix was... there is no ending to this story


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## piranha

*thanks goodman furnace flash/blink 1 led issues was pressure switch*

I had the same issues as above.. Goodman furnace/ led flash code 1 blink.. everything cycled except gas valve.. One of the lower pressure tubes had small amount of condensation in it.. drained /blww out tubes.. flushed the drain trap.. everything was good to go.. unit would run for a bit cycle off. I'd empty the drain line by hand and unit would run.. Tried cleaning everything again.. same issues.. Then I shimmed the unit up and watched the drain trap start working..

That was the fix for me .. shimming the unit on one side. Thanks to the poster for the information..


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## Douglasrome

Do you even need the factory trap? What if I eliminate the trap,
use whatever pvc fitting(s) to make it work? my floor drain, which
is very lose to the furnace corner, has a p-trap. thanks, douglas


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## rick31797

*trap*

i was under the impression the reason for the trap is too purify the condensation before it is sent out to the ground,i am thinking inside the trap is charcoal.


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## hvac benny

The trap ensures that only the condensate comes out and not the exhaust fumes from the furnace.


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## rick31797

*trap*

So it very important too keep the trap in place and not just bypass it.


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## Douglasrome

if the trap has charcoal, and it's a sealed unit, almost 
impossible to clean? how could exhaust gases pass thru
to the drain system? about the trap somehow purifying
the condensate, how far do we wish to take save the planet?
My daughter's house, Carrier 58MXA, we blew thru the tubing,
got gurgiling sound, jumpered the wires off the pressure switch,
and furnace ran for 3-4hrs, repeated this that's where we're at now.
I'm thinking eliminate the trap, should cure water in the drain lines.
what you say? thanks, Douglas


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## rick31797

*traP*

I am guessing what is inside the trap, its not just hollow, it is sealed, and i have just run water through it to flush it out.


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## hvac benny

Douglasrome said:


> if the trap has charcoal, and it's a sealed unit, almost
> impossible to clean? how could exhaust gases pass thru
> to the drain system? about the trap somehow purifying
> the condensate, how far do we wish to take save the planet?
> My daughter's house, Carrier 58MXA, we blew thru the tubing,
> got gurgiling sound, jumpered the wires off the pressure switch,
> and furnace ran for 3-4hrs, repeated this that's where we're at now.
> I'm thinking eliminate the trap, should cure water in the drain lines.
> what you say? thanks, Douglas


• there is no charcoal on the trap
• the condensate is drawn from the exhaust as it cools in the secondary heat exchanger, so the exhaust could very easily come out the drain (they're coming from the same place). 
• the pressure switch is a safety and should NEVER be bypassed. 
• Carrier has had issues with their secondary heat exchangers. Your daughter's could be plugged. It's also common for the primary heat exchanger to crack when the secondary gets too plugged. You should have it checked by a qualified gas fitter. 
• the furnace is designed to run with that trap. It's there for a reason, do not remove it.


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## hvac benny

rick31797 said:


> I am guessing what is inside the trap, its not just hollow, it is sealed, and i have just run water through it to flush it out.


Soak it in bleach and hot water to loosen up the gunk inside of it. If it gets to the point of being plugged, you really should have your secondary heat exchanger inspected. All ports on the trap should be clear (you should be able to blow through them all).


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## rick31797

*trap*



> • there is no charcoal on the trap
> • the condensate is drawn from the exhaust as it cools in the secondary heat exchanger, so the exhaust could very easily come out the drain (they're coming from the same place).
> • the pressure switch is a safety and should NEVER be bypassed.
> • Carrier has had issues with their secondary heat exchangers. Your daughter's could be plugged. It's also common for the primary heat exchanger to crack when the secondary gets too plugged. You should have it checked by a qualified gas fitter.
> • the furnace is designed to run with that trap. It's there for a reason, do not remove it.



You said alot but you never said what is inside the trap.


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## hvac benny

rick31797 said:


> You said alot but you never said what is inside the trap.


Lol, a trap is full of water (or condensate in this case). If there is no water in it, then it's empty. Think of the trap under a sink- same idea.


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## hvac5646

rick31797 said:


> You said alot but you never said what is inside the trap.


I agree..the poster said IF the has charcoal in it. The trap is hollow.


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## hvac5646

The charcoal condensate filter (condensate neutralizer is the term coined by the MFG all ICP condensing furnaces, including Comfortmaker) is nothing more then a short length of 1.5" pvc tubing filled with charcoal and capped at each end w/a 1/2 or 3/4" female fitting to hook up condensate line.


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## Douglasrome

thanks 5646, good info. here's where we're at, xmas eve morning,
who wants to mess with a furnace? we took the trap out, a lot, lots,
of water came out of the fat hose, the little one not so much, in fact 
none. we ran the furnace, pressure switch hooked up, trap out. it ran
like it's supposed to first cycle of the stat, sat satisfied, it shut down.
But it would not start up the next time the stat called for heat. We opened the main 110v disconnect, waited about 5min, closed the disconnect and it fired right up. don't have a clue what's with that?
tried flushing the trap best as we could just by running water. little
girl didn't have any bleach or vinegar, young kids. anyway got it
flushed pretty good, had decent flow thru it. hooked everything back up
put trap back in, pressure switch hooked up correctly. it's been
working fine, so far so good, I'd say about 3hrs now. 

lessons learned: you can't jumper the pressure switch, if you do, it will
work for only one cycle of the stat, then you have to re-set main
110v.

you have to have the trap installed, don't make sense to me but
same thing, it will work for only one stat cycle, then you have to 
re-set. that's what stumps me the most, i don't know what the 
trap does, it ain't under pressure, it ain't a P-trap like under your
sink, the thing is just a box with three openings and it's filled with 
charcoal or something. 

instead of taking the chance, we're going to buy a new trap and
hopefully get several years out of it untill it plugs up again.
when the new trap comes, we're going open up the old one and 
see what makes it tick.

thanks, douglas


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## hvac5646

Douglasrome said:


> thanks 5646, good info. here's where we're at, xmas eve morning,
> who wants to mess with a furnace? we took the trap out, a lot, lots,
> of water came out of the fat hose, the little one not so much, in fact
> none. we ran the furnace, pressure switch hooked up, trap out. it ran
> like it's supposed to first cycle of the stat, sat satisfied, it shut down.
> But it would not start up the next time the stat called for heat. We opened the main 110v disconnect, waited about 5min, closed the disconnect and it fired right up. don't have a clue what's with that?
> tried flushing the trap best as we could just by running water. little
> girl didn't have any bleach or vinegar, young kids. anyway got it
> flushed pretty good, had decent flow thru it. hooked everything back up
> put trap back in, pressure switch hooked up correctly. it's been
> working fine, so far so good, I'd say about 3hrs now.
> 
> lessons learned: you can't jumper the pressure switch, if you do, it will
> work for only one cycle of the stat, then you have to re-set main
> 110v.
> 
> you have to have the trap installed, don't make sense to me but
> same thing, it will work for only one stat cycle, then you have to
> re-set. that's what stumps me the most, i don't know what the
> trap does, it ain't under pressure, it ain't a P-trap like under your
> sink, the thing is just a box with three openings and it's filled with
> charcoal or something.
> 
> instead of taking the chance, we're going to buy a new trap and
> hopefully get several years out of it untill it plugs up again.
> when the new trap comes, we're going open up the old one and
> see what makes it tick.
> 
> thanks, douglas


ICP traps are a pain. You can't dis-assemble them to clean them thoroughly, the sectional-lized interior construction does not let you see if any muck remains after cleaning it.

Keep in mind the trap might not be the REAL problem.

Venting or the board are what comes to mind as I sit here just reading the symptoms you posted. Seeing problems first hand is (obviously) better than reading about them.

Merry Christmas.

But, it's the next best thing


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## Douglasrome

it'sa been working fine, 3days now. s-i-l is going to order
a new trap $15 from pexsupply. thanks, douglas


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