Carrier 58MVP Furnace Problem-Inlet Pipe Ice

Izya001

I have installed an high efficiency Carrier 58MVP Weather Maker Infinity furnace.

Each year I have a problem - the inlet pipe would ice up and shut off the heater. I have to go out in the middle of the night in freezing temperature to unclog the inlet put from ice.
I would need to say that it gets iced up even when it is not snowing.

The outlet pipe that exhaust hot and humid air is facing the ground, the inlet pipe is above it and horizontal.

Please help.

Izya001

HVAC Doc

How much slope do you have on the pipe going back to the furnace? Should be approx 1/4" slope so water drains back and isn't as prone to freezing around the intake. You might also see if you can extend the intake pipe out a few inches further as not to suck in the moist exhaust air or put an elbow on it facing horizontal away from the exhaust. This of course is if you have enough footage left to add an elbow.

Izya001

On the outside the inlet ( which is horizontal ) is separated by one foot from the outlet pipe openning ( facing down ).

Further, inside the hose, the inlet pipe slopes down to the furnace at about 30 degrees.

Thanks.

Teetorbilt

My guess is that the hot, humid air from the exhaust is rising and entering the intake duct where it freezes as condensate.
As a test, duct the exhaust off to one side and downwind from the prevailing winds. Keep the test pipe as short as possible, give it some rise and add a 'weephole' to allow any condensate to drip out. If this works, contact a pro and have it done permanently.

Izya001

Strangeley, Carrier customer service said that no such such problems were recorded.

Teetorbilt

Tell them to come out and do whatever it takes to fix it. Tell the the guy in the cozy office and chair that you would like for him to do this personally.

HVAC Doc

As I mentioned before, and Teetor as well now, you need to see if you can extend the intake pipe out a few inches further as not to suck in the moist exhaust air or put an elbow on it facing horizontal away from the exhaust. You get freeze ups in 3 common instances: if your pipes aren't sloping back towards the furnace or you are sucking back in moist exhaust, or you have them buried under snow. Carrier will not have a record of problems because it is not a flaw with the unit itself, just how it is vented and recirculating (most likely).

hoss

your termination is wrong, the intake should be 45' down no less than 12" above anticipated snow line and your exaust should be higher than that and should be 90' up ~8" and 90' away from home. also make certian that there are no other vents within 3 feet eg. dryer or power vent water heaters.

Izya001

I tend to agree with you - if exhaust pipe is ABOVE the inlet pipe, then the warm and humid air ( which alwais goes up ) will never get into exhaust pipe.

In my case, however, the inlet pipe is one foot above the exhaust, and therefore, sucks in all warm and humid air, and therefor gets iced up.

I wishh I could attach a pictute - I just made a butiful digital picture of a glogged with ice inlet pipe.

Thanks for your support.

Izya001

Comfortman

You wouldnt happen to have tight metal mesh used as birdscreen would you?
If you do it should be larger than quarter inch mesh
The termination shouldnt matter much, sometyhing else is happening
The Trane sidewall terminations are side by side and only 1/2 inch apart with no 90s

NickTech

I would consider having the installer return and utilize a concentric exaust and intake termination unit. this is a pipe in a pipe type device where the intake air pipe surrounds the exaust pipe. this would allow any frosting that could occur to thaw or not freeze at all. :Thumbs: here is a web site with a PDA file that shows what i am talking about. see page 7 of this site. http://www.weil-mclain.com/FTP/Ultra%20310/550141965071403andadd.pdf#search='vent%20terminati ons%20concentric'

yeh i know is a mile long!

Izya001

YES,YES, YES - the inlet pipe has a small mesh ( I guess against birds ). The ice was closing the mesh.
I have called a Carries Authorized Dealer - he cam and removed the mesh ( and charged $75 for a visit. ) I have objected - this is just to circumvent a problem, not to cure.

So I went to home depot and bout a thing - it is for gutters - to prevent leave going into downspout. It has much larger mesh and looks like a mesh ball.

Hope it may help. If the front gets clogged with ice, the sides of this mesh ball are still able to take in air.

Please advice if this is a good way to cure this problem or just a band aid.

I am surprised why such a reputable company like Carrier could not find a similar problem and their problem data base.

Thanks

Izya001

Comfortman

1/2 inch mesh should keep out birds but wont be so small as to close up with ice
this typically happens when the termination is on the side of the house that doesnt get much sun
i dont know about the "ball mesh" youve got but the larger the gap between the wires the better
this isnt circumventing the problem by the way, the mesh is the problem
combustion produces alot of moisture
when the furnce shuts off, all that moisture is still in the venting system
heat flows naturally to cold, bringing that moisture to the vent termination
where it condenses on and clings to the mesh......you know the end result there....lol
are you in a real cold area?

tinner73

can you take the exhaust pipe and turn the elbow so it faces up. add a short joint of pipe (to get it above the inlet pipe) and a second elbow facing out away from the building. keep the birdscreen too.

Izya001

Thanks for advice.

That is what I did.

I have made the exhaust above the inlet. It should help.

Thanks

Izya001

tinner73

i'll send you a bill.

Izya001

Thanks

Check in the mail