Making an A frame for a heater vent

Garandman · Nov 28, 2015

We have a Rinnai wall heater in NH. There is an exhaust vent to outside about 12" above ground. It snows a lot here and if the snow covers the vent while we are away, the unit will not run.

I guess most people make an A frame to shield it. I'm obsessing over the height, width, and whether to plank in the sides or not. We can easily get four feet of accumulation though I clear it a few times a winter.

Anyone built one? I'm probably making this too complicated....

CCWKen · Nov 28, 2015

I don't know the building codes but why not just extend it upwards and put a rain cap on it? Typically, vents need free air around them to work.

Garandman · Dec 22, 2015

It's what everyone seems to do around here. Took five minutes.

Oaktree · Dec 22, 2015

Who are the idiots (no offense if it was self-installed) who vent these things near ground level in parts of the country where there's snow? They did the same thing with a direct-vent oil furnace at a friend of my wife's house. One would think that building codes would address this potentially hazardous situation. Or at least common sense.

When we had a direct-vent furnace put in a few years ago the contractor insisted that the vent be at least 4' above ground.

KennyG · Dec 22, 2015

I assume this is a 95+% efficient furnace. We have no shortage of snow here and they are all vented horizontal close to the ground (if they are installed low or in the basement). I think they are not supposed to have a significant vertical run. A simple cover will do it. I'm fortunate that mine vents under the deck. The only bad point on that is I had to run a lengthy inlet to make sure it was separated from the exhaust.

westcliffe01 · Dec 23, 2015

Usually, the reason they are close to the ground is because the main run is in the ground floor joists. There are "snorkel" contraptions for raising the discharge height but they are expensive. They have to be double or triple wall to meet clearance to combustibles requirements (that entire wall looks like it will burn). That kind of thing will not pass a building inspection here where I live in MI.

kenmac · Dec 23, 2015

Most if not all codes, manufacture instructions state to terminate vents a min. of xxx above grade, and xxx above grade in areas prone to have heavy snow..
You shouldn't install an appliance how ever you want ,Just because you can't meet min. code or manufacture requirements

Garandman · Dec 23, 2015

This Rinnai wall heater was installed by a dealer and the vent pretty much comes straight out the back and through the wall. The original unit was there for at least 10 years. We replaced it with a newer model this summer but the vent is in exactly the same place.

Bottom line, this keeps snow out of it, and that's what I needed. It's around 18" off the ground.

kenmac · Dec 23, 2015

Guess you have to do what ever works.. I would have never install a vent existing or other wise that low in an area that gets 4 feet of snow.. The mfg. instruction sheet may state a min. of 18'' off the ground for an area like I'm in. but , not yours...

westcliffe01 · Dec 23, 2015

The image above is from a current Rinnai tankless water heater install manual. One can note how they have added the image clarifying height above the "anticipated snow pack" to the install manual. Perhaps it was open to interpretation before leading to the kind of situation described by the OP. Best course of action would be of course to raise the unit to a more acceptable height in the first place.