Water in air intake pipe and inside furnace.

[Larryk1]

My Tempstar high efficiency furnace has water draining down the air intake pvc, and into the furnace all over the burner and gas valve etc. Furnace is 6 years old, but I never noticed this problem before.

The intake and exhaust are both vertical up through the roof 2" pvc. They are 6ft long between furnace and roof, and 2 ft outside above roof. Intake has 2 elbows and points back down toward roof. Pipes are 20" apart with exhaust 6" higher than intake. In 10 degree and colder weather, I get some icicles forming out of intake opening.

I'm wondering if warmth from the furnace could be rising up and causing condensation to freeze? Both pipes are in a heated space until they pass through the roof.

The inducer motor was replaced last week due to pressure switch shutdowns. But this was during a below zero sustained temp cold snap, and I'm wondering if the intake could have been iced closed? Temps were above freezing a couple days, so I'm guessing it all thawed out, but now we are going below zero again, and I am worried it will ice up again and damage my new inducer.

Has anyone had this happen? Should I try insulating the pipe up to the roof?

Any suggestions are appreciated!

Larry in frigid northern Wi.

[jtrammel]

The exhaust gasses may be blowing onto intake and freezing on the intake. The gas valve MUST be replaced if its gotten wet for safety.

[LibertyTree]

Make sure the elbow that was on the intake pipe outside didn't come off. Sometimes they don't get glued and can come off later in time.

[BaldLoonie]

Does the exhaust blow straight up?

[Larryk1]

The exhaust does blow straight up, and the end of the pipe is cut at an angle away from the intake.
Thanks for your replies!
The elbows are glued on the intake up there on the roof.
I dried the water mess inside the furnace with a hair dryer, and furnace is working. Last night it was -2 F outside, and there is evidence of frost on the intake on the roof. I don't want to think of replacing the smartvalve until the condensation issue is solved though.
This morning I talked to the guy that installed the furnace in 2006, and he said to try some pipe insulation on the intake pipe inside the house. That is ok with me, but why is this happening now after 6 years?? Tonight is supposed to be 20 below zero, so we'll see if i can find some insulation for 2" pipe here in my small town. Ha Ha
Please let me know if anyone thinks of anything else.

Thanks!

Larry

[firecontrol]

Did this ever happen before the new inducer was installed? Was the new inducer installed by the original furnace installer or someone that is a Tempstar dealer? Do you notice any difference in how the furnace operates now with the new inducer?

The water and frost could be an indication of moisture going up the intake pipe and not down it. This could happen due to a number of reasons. Is the furnace located in the conditioned part of your home?

If the frost and ice is actually coming from exhaust gas condensation then the problem needs to be found and corrected sooner than later as this moisture is corrosive and can cause some serious and expensive problems if left to continue.

[pacnw]

His do the pipes run through the roof?
If they are run in an unheated area, they should be insulated. Refer to install instructions for specifics.

[AC Al]

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[Cosmicmuffin]

Is it possible you are getting your "combustion air" from inside the home.,and not thru the intake!Door off..,seal compromised?

[Larryk1]

Hi, and Thanks again for your replies.

Ok, the pipes don't go through any un-conditioned area inside the house. The furnace is in a closet, since there is no basement, and the ceilings follow the roof line. (no attic) So the only area that would be un-conditioned would be between the ceiling and roof. (approx. 12-14")

The doors are all sealed good on the furnace, and it definitely draws the combustion air from outside. I know this because when the unit is running, the intake pvc gets cold to the touch, as does the metal on top of the furnace where the intake goes in.

I have read the install manual numerous times, and the pipes are positioned according to the roof termination instructions. Tempstar recommends that for sustained below zero climates, the intake and exhaust should be at least 18" apart, and mine are at 20".

This problem did occur with the old inducer also. I noticed the water for the first time when the pressure switch fault was not allowing the unit to light. The only difference noticeable with the new inducer, is that it is much quieter. The old one was really making noise. With the door off, it was down right loud.
The man that changed the inducer is both a Tempstar dealer, and the original installer. He did seem to do the proper testing of the inducer with his manometer etc. but he doesn't seem to know why this condensation is occurring now.

I did get some 2" insulation today and I just finished insulating the intake up to where it goes through the roof. The local HVAC wholesaler J.H. Larson was kind enough to sell me a 6ft. piece.The man there suggested re-plumbing the intake pipe to add a condensate TEE, and run the water into the condensate drain. But I don't know if it would help with the icing outside at the intake?
it is zero outside now, and supposed to be -20 or colder tonight, so I'm hoping I have no issues tonight. I notice after running last night and today, there are a couple frost icicles hanging from the intake again. Is that normal in this cold weather?

This is a real head scratcher for me. I am a service manager/Tech. at a local Evinrude outboard dealer, and when I can't figure out a service issue, it really bugs me till I do solve it.

Thanks, and I will let you all know if the insulation helps.

Larry

[jpsmith1cm]

AC Al

This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

You can find the rules for posting and qualifications here.

Additional infractions may result in loss of posting privileges.

[Larryk1]

Mr. moderator,

I keep seeing these warning messages addressed to AC AL.
That is not me. I am Larry, the guy that started the thread. Maybe there is a mix up on the names in the database or something. I am Larryk1 not AC AL.

Thanks

[jpsmith1cm]

I'm well aware of who you are, Larry.

AC Al is a poster who was not authorized to post in this thread. The warnings are directed at him.

[jtrammel]

It doesn't get anywhere close to that cold in my neck of tge woods, rarely below freezing, so I don't run into pipe freeze problems much but I have used this http://m.acehardware.com/product/ind...ductId=1292305 to keep water lines from freezing in certain instances.

[Larryk1]

Well, after insulating the intake pipe, it ran ok last night and I see no water dripping in.

There is a frosty coating on the intake elbow opening that I hope will not close up the pipe. It was -22 last night though, and never got above zero today. Supposed to get to 10 above tomorrow. Yea!
I lowered my blower speed to medium from high-medium while checking the temp rise between return and supply. It feels much more comfortable and quieter now.

Thanks for everyone's help!

Larry