High Efficiency vents too close to AC?

(Kevin Mikottis) #1

I have High Efficiency vents 2 inches from AC condenser. Even though makes for a pretty look, it seems like a bad idea all around. But I can’t find concrete sources to back me up. Please help with URLs to prove my point.

In addition to the potential corrosion concerns, as I see the water vapor I can also imagine continual build up of ice on the the AC fins. Most importantly, with the snow on the AC unit now it seems very plausible that that both the intake and exhaust could get blocked as the snow cap drifts and fills in the area between wall and AC or Vent and AC.

HE Vents vs AC - Google Photos

Google Photos

Google Photos

Google Photos

(Chuck Evans, CMI TREC 7657) #2

Clearance requirements will be documented in the installation instruction manual for your listed gas appliance. Do you know the make and model number of the gas appliance?

Beyond that, if you’re concerned about snow blocking the intake, which appears reasonable, I don’t think that there’s anything to prevent you from extending them somewhat higher, though access may be tight for the intake.

Excerpt from the DOE document on HE Natural Gas Furnaces

(Kevin Mikottis) #3

@Chuck Evans - Thanks!

I did spend some (too much) time digging through documents for these installed models:
Variable-speed 90+% Efficiency Gas Furnace - Gas Furnaces | Bryant
Single Stage Air Conditioner - Air Conditioners | Bryant

There is a lot to sift. Still holding out hope there is industry guidance on this, as I imagine this would not be specific to the particular brand/models.

(Chuck Evans, CMI TREC 7657) #4

Assuming that you are in the U.S. you could refer to the DOE document that I posted the link to earlier for “industry guidance”. The bible is going to be the manufacturer’s installation instructions. All model building codes refer to the manufacturer installation instructions for listed appliances. Your HE furnace is a listed appliance. See page 64 of your manual https://www.utcccs-cdn.com/hvac/docs/1009/Public/01/II926TA-10.pdf for snow reference other figures for clearance to fixed objects. You’re unlikely to find a reference for clearance to A/C condensers specifically.

Don’t expend more time/effort to prove the point than what’s required to actually make the change.

(Erik Schmidt) #5

Don’t forget to check AC condenser installation instructions as well as gas appliance installation instructions.
Aside from what the manufacturer says to do or not do, did you notice any problems or potential problems when the equipment was running? High efficiency exhaust contains a lot of moisture, which can be more corrosive than pure water because it is acidic, so if the exhaust is blowing on something that can be damaged, report that. High efficiency air intake should not be a problem for AC equipment. AC equipment or anything else should not be close enough to block HE appliance intake or exhausts.