Snow and Comb Air Inlet

JUGHNE

-19 or colder last night. Woke up to a 62 degree house. Not good when used to 72-74.
This is the north side of the house with an inside corner where I am standing.
The snow drift is over 6' high so makes the 4' dog fence ineffective as they can just walk over the fence.

We have been blessed with 40-50 MPH winds giving a wind chill of almost -55 degrees.
Monday may warm up to -5 amb.

I went out last night and cleaned snow away from the bottom.
Usually the ground is clear right at the house in that location.

The Knight KBN 80 was in lock out stating "APS Closed".
Upon reset it was obvious the inlet was plugged, the inducer fan sounded like someone with a plastic bag over their head. Taking comb air out of the basement for now.

The TS book states "APS OPEN" as a fault..."Air pressure switch contacts are open".
No mention of "APS Closed" in the TS book.
Only one air pressure switch and it is NC. I would guess it looks for it to be closed before blower starting which would then open it with negative pressure.

This design of air/exhaust wall terminal has been in place since 1996 and has had perhaps only one other issue in the past. (Mainly because this is also my AC bone yard and some unit was close to the exhaust).

I will add a Tee with plug in the comb air pipe right at the boiler in the event this happens again.
I have done that with every condensing furnace/boiler except my own...

pecmsg

How often do you get weather like that. 

Just like opening the cabinet under the kitchen sink to keep the pipes from freezing. It’s something to look for under those condations!

JUGHNE

Wind, low temp and snow.....we seldom get all 3 at the same time. (The Perfect Storm)
That snow drift was recycled by the wind from the back yard.

The south front yard has spots you can see the grass.

That damn 4' dog chain link fence caused most of that drift, working as a snow fence.

I neglected to put up the 3 runs of 50' of snow fence this year and now paying for it.

Most of our sinks are on an inside wall, only 2 of the 8 are on outside walls. The kit sink is in the center of the house and over the boiler room.

Every house I have plumbed up here has no pipes inside an outside wall. Supplies up thru the floor.

My unheated attached garage is down to 41 degrees, it has plumbing and never frozen.

hot_rod

They look ugly. But the outside snorkel is a good way to both separate intake and exhaust and raise them up high.
No uglier than min split line sets all over the side of homes, I suppose😗

Seems intake from inside is not a problem?

PC7060

Wow, @JUGHNE, glad you got it worked out.  I sure don’t miss that weather.  We moved my mom from Nebraska to Florida last summer to be closer to family. I’m sure she doesn’t miss it either. 😜

EdTheHeaterMan

Could not pass up this chance to rub it in!

JUGHNE

Plenty of combustion air in the basement, have a 6" fresh air inlet in the boiler room.

Hoping to not have to do the 2 pipe extensions as this has worked well until now.

Years ago I did see a combustion air tee with a flapper that would open if exterior inlet was plugged.

I think Johnstone supply had them in a flyer. Have not seen anything of them since.

I could imagine them being troublesome and sticking shut as they would seldom be used.

hot_rod

Good that you were home to catch it.

JUGHNE

Yes, lucky, although we seldom go in this type of weather.

And if someone check the house and found low temp inside there is a shortage of people who might know how to fix the problem.

Another reason to get the tee/plug in the comb air pipe. Anyone could unscrew the plug and reset the boiler.