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jeffeg 12-21-2012 08:36 PM

furnace vent gurgling
 
1 Attachment(s)
Bought this house about 2 months ago and the furnace vent pipe gurgles. the furnace is a 90% Amana 70k BTU 3 ton airflow with induced air.

in the picture you can see the 2" PVC exhaust vent is sloped towards the elbow and I can hear the condensate being blown around in there.

If the vertical pipe slipped an I can push it up an inch, that would be the easiest...but...

To repair, I was thinking about 1) disconnect the vent pipe from the furnace via the rubber coupling 2) using a hacksaw and cutting the vent pipe about 10" above the elbow 3) cutting off what is necessary to properly slope the pipe towards the furnace 3a) cleaning out all the PVC shavings 4) putting it back together with a coupling. 5) hooking the pipe back up to the furnace.

My questions are:
1) anything wrong with the above?
2) any special glue I should use, or is standard PVC cement sufficient
3) if I wait until Spring to do this, what would be wrong with that.

thanks!
Jeff

ben's plumbing 12-21-2012 08:48 PM

Quote:

Originally Posted by jeffeg (Post 1077707)
Bought this house about 2 months ago and the furnace vent pipe gurgles. the furnace is a 90% Amana 70k BTU 3 ton airflow with induced air.

in the picture you can see the 2" PVC exhaust vent is sloped towards the elbow and I can hear the condensate being blown around in there.

If the vertical pipe slipped an I can push it up an inch, that would be the easiest...but...

To repair, I was thinking about 1) disconnect the vent pipe from the furnace via the rubber coupling 2) using a hacksaw and cutting the vent pipe about 10" above the elbow 3) cutting off what is necessary to properly slope the pipe towards the furnace 3a) cleaning out all the PVC shavings 4) putting it back together with a coupling. 5) hooking the pipe back up to the furnace.

My questions are:
1) anything wrong with the above?
2) any special glue I should use, or is standard PVC cement sufficient
3) if I wait until Spring to do this, what would be wrong with that.

thanks!
Jeff

you have the right idea make sure the whole pipe run is sloped back to furnace ....if you leave it go it will at some point shut down ..repair it now ...or it will leave you in the cold...ben sr

HVAC1000 12-22-2012 01:25 AM

I would suggest using Christy's Red Hot Blue glue. I love the stuff because it seals pipe nicely. But any PVC cement would work well

Legacyairsystem 12-23-2012 12:13 AM

venting
 
undo pipe at rubber, take off an inch or two of pipe with saw at bottom, tighten it up, check your slope, no glue needed

hvac benny 12-23-2012 12:32 AM

Quote:

Originally Posted by Legacyairsystem
undo pipe at rubber, take off an inch or two of pipe with saw at bottom, tighten it up, check your slope, no glue needed

I think you're looking at the picture sideways.

HVAC1000 12-23-2012 02:22 AM

I would cut pipe about 5 to 8 inches above elbow, cut off an inch or two then marry the two raw ends with a no hub rubber coupling and make sure the horizontal solidest back into the furnace. The rubber coupling farther up on the pipe make certain repairs easier in the future

HVAC1000 12-23-2012 02:24 AM

If you really wanted to get fancy too you could replace that 90 elbow with two 45 elbows

jeffeg 01-06-2013 03:39 PM

1 Attachment(s)
Thanks for the advise on the no-hub coupler - it helped a lot, I don't think I would have been able to make a PVC coupler work (see picture.)

there's not much play in the pipe penetrating the roof, so it would have been difficult getting a slope with a rigid coupler.

note: this is a horizontally mounted furnace. there is about a 1" per foot slope back to the furnace because I ended up flipping the pipe around (i.e. the hoizontal became the vertical and vice-versa, it fit better this way, if I shorten the horizontal pipe, I start to lose the slope again.

I thought this was going to be a lot easier than it was...

notice that it's not a clean fit on the no-hub coupler, but it is secure and does not leak vent gas.

??? my question-- is the cock-eyed fit on the coupler a problem? If it is a problem, can I wait until it warms up before I trim a little off of the horizontal pipe?

Any other solutions if what is in the picture is a no-go?

thanks a lot everyone,
Jeff




Quote:

Originally Posted by HVAC1000 (Post 1078372)
I would cut pipe about 5 to 8 inches above elbow, cut off an inch or two then marry the two raw ends with a no hub rubber coupling and make sure the horizontal solidest back into the furnace. The rubber coupling farther up on the pipe make certain repairs easier in the future


HVACTECH96 01-06-2013 10:03 PM

As long as condensate can drain back to furnace it should be ok.

HVAC1000 01-07-2013 12:30 AM

from what I can see it all looks good. the cock-eyedness of the pipe is fine as long as the PVC is fully inserted into the coupling and it is screwed down tight and is not leaking at all. i am glad that the no hub worked well for you, they are such a quick and convenient repair solution

carmon 01-07-2013 01:35 AM

Quote:

Originally Posted by HVAC1000 (Post 1088015)
from what I can see it all looks good. the cock-eyedness of the pipe is fine as long as the PVC is fully inserted into the coupling and it is screwed down tight and is not leaking at all. i am glad that the no hub worked well for you, they are such a quick and convenient repair solution

Illegal here... not to code :jester: ..... I see nothing wrong...hope it works out....:thumbsup:

HVAC1000 01-07-2013 02:03 AM

Quote:

Originally Posted by carmon (Post 1088037)
Illegal here... not to code :jester: ..... I see nothing wrong...hope it works out....:thumbsup:

its perfectly fine to do that here as long as its not leaking. canada has different regulations and much stricter enforcement so it all depends on where Jeffeg is from. the only issue (around here at least) is some damage to your personal pride for not having straight lines. personally I would make it straight to make it look professional but thats not saying Ive never left things like that in my beginning days.

jeffeg 01-07-2013 02:17 AM

thanks
 
Thanks for the feedback... I agree, it does look sloppy... my problem is the vertical pipe going through the roof doesn't have much play, so it's going to be difficult to get any slope, 2" pipe isn't very flexible, but it could be better - I was looking around this evening - would it be OK to use a PVC flexible elbow?
like this one -> http://www.homedepot.com/h_d1/N-5yc1...1#.UOp4sXf5WQ4



as far as leaks, I just went by feel - air flow, heat and condensate -

should I check the joints with soapy water?

thanks. these forums are great!
Jeff


Quote:

Originally Posted by HVAC1000 (Post 1088047)
its perfectly fine to do that here as long as its not leaking. canada has different regulations so it all depends on where Jeffeg is from. the only issue (around here at least) is some damage to your personal pride for not having straight lines. personally I would make it straight to make it look professional but thats not saying Ive never left things like that in my beginning days.


carmon 01-07-2013 08:38 AM

that clamp should not leak...as far as an flexible elboe you posted....definately not here... maybe you are allowed in your area...not sure....

hvac benny 01-07-2013 08:47 AM

I would have used two 45's instead of the 90. The first 45 would be right after the pipe left the unit, eliminating most of the horizontal pipe, and allowing the vertical pipe to remain straight.


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