Return Air

[inspect4u]

On today's inspection, I found the a/c-heat unit sitting on an open raised platform in the utility room. This is a new installation and the old unit had been located in the attic. There is no door installed on the utility room. My question is "Can this unit get adequate return air, being in the open like this?" The unit draws the return air from the bottom and there is a filter in place. I have seen them on raised platforms in a hall closet with the return air in the same manner, however, the plenum was enclosed with an outside grill.

Mike M

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[Phillip]

It will get just as much return air as the other set up you where talking about.

How close is the thermostat to the unit.

[inspect4u]

Approximately thirty feet, the kitchen is across the hall from the utility room and the thermostat is located on the other side of the kitchen in an open hall way. Is this an ok install?

Mike M

[hausdok]

Hi,

That looks like a load of laundry on the floor. If it's a gas appliance and is located in the same room as a laundry the installer may have violated the manufacturer's listing.

Then there's the issue of proximity to clothes dryers which want to depressurize the entire house being close to the furnace.

ONE TEAM - ONE FIGHT!!!

Mike

[inspect4u]

Thanks Mike,

I'll check into the manufacturer's spec on it being located in a utility room. It is a gas Payne unit. I hadn't thought about the dryer which is located right across from the unit within five feet and I know the heat and humidity from the dryer has to play havoc on the return air.

Mike M

[Erby]

inspect4u: Mike is referring to the dryer sucking combustion air out of the furnace, not heat and humidity. Heat & humidity from the dryer mostly go out the dryer vent pipe.

Mike: Typing faster than you're thinking????? "the installer may have manufactured the manufacturer's listing."

I know you meant violated, (didn't you?).

[inspect4u]

Erby,

Ok, let me try to understand this. Then the dryer could affect the burning operation of the furnace? I know most of the heat and humidity go out the vent, but not all, and if the unit is in a/c mode wouldn't the return be pulling the heat in, given the close vicinity? It's my understanding that the whole purpose of return air is so that the unit is recirculating warmer or cooler air, depending on mode set on, so that it doesn't have to work so hard all of the time cooling or heating the inside air. Myself, I'm in the learning mode, so am I in the ballpark or way out in left field?

Mike meant the installer may have manufactured his own list in lieu of the manufacturer's listing. I think???

"You're never too old to learn, or to un-learn."

Mike M

[hausdok]

OK,

Two issues with a laundry in close proximity to a gas furnace. First one, corrosive elements in the air that get pulled into the heat exchanger along with combustion air and can corrode the heat exchanger. Yeah, I know, that sounds like a stretch, but some manufacturers actually prohibit that. The think that last time I looked at the instructions for a Payne gas furnace they specifically addressed the issue of using the device in close proximity to chemicals like bleach and detergents.

Second issue, a clothes dryer sucks in huge amounts of air. Having a clothes dryer in close proximity to a gas furnace is like having a return air duct within 10ft. of the combustion chamber, which is prohibited by code. When that dryer is operating, it's pulling in air all around it and, in some cases, can cause the furnace to backdraft, pulling the exhaust backward down the flue and into the room where the dryer is located. If there's a water heater next to the furnace that is sharing the exhaust flue, it's even more serious, because if the exhaust from the water heater is pulled into the laundry below the draft diverter, instead of going up the flue, it can establish a draft into the house instead of up the flue. Again, it's rare, but it's happened and it's killed people before, so that kind of stuff has to be paid attention to.

If you've got a gas dryer, located in the same room as a gas furnace and/or a gas water heater, you must ensure that there is sufficient volume in that space to provide sufficient air volume for all of those appliances to combust properly. You'll want to calculate the required volume based on the total Btu/Hr usage of all gas appliances in that room using the rule of thumb of 50 cu. ft. per 1,000 Btu. If there's not enough volume, then you need to check the manufacturer's requirements for each appliance, see what their minimum requirements are, and see if you've got enough. If not things need to be reconfigured so that they have sufficient volume or they need to obtain the air from elsewhere; outside for instance.

Lastly, and I should have addressed this before, unless that's a direct vent appliance that's getting its combustion air from outside, the return air can't be beneath it in the same room because that violates the rule that prohibits the return within 10ft. of the burners. Hell, even without the dryer in there, you're still depressurizing the area around the furnace and the same bad things that can happen with a dryer too close can still happen.

Are you quite sure that an HVAC pro installed that unit? It's starting to look like a DIY job.

ONE TEAM - ONE FIGHT!!!

Mike

[Jim Katen]

What a trashy installation. In addition to everything Mike said, what happens when someone leaves out the filter and the cat walks underneath it?

Meeeeeeeeooooooooooooow!

- Jim Katen, Oregon

[inspect4u]

Thanks guys,

I'll advise the new buyer of the possible consequences. No, I'm not sure who installed the unit, I know the homeowners just replaced the gas water heater and I won't even go into all that's wrong with that installation. It is in a closet just in front of the furnace, however, it has its own upper and lower combustion air and exhaust vent, and has a door installed. The dryer is electric. As far the cat, well, he's on his own! [xx(]

Mike M

[inspect4u]

Mike,

I have googled every search term I can think of for Payne's installlation instructions and can't find anything. Any ideas?

Thanks,

Mike M

[Jim Katen]

Originally posted by inspect4u

Mike,

I have googled every search term I can think of for Payne's installlation instructions and can't find anything. Any ideas?

Thanks,

Mike M

Try searching for BDP or Carrier.

- Jim Katen, Oregon

[inspect4u]

Thanks, Jim. I tried under Carrier and still couldn't locate instructions.

Mike M

[Jim Katen]

Originally posted by inspect4u

Thanks, Jim. I tried under Carrier and still couldn't locate instructions.

Mike M

It's possible that they have it in a protected area of their web site. Contractors don't appreciate it when the manufacturer makes the installation instructions available to the public - people might start to install their own furnaces. That's why contractors dislike Goodman so much, they sell to anyone.

- Jim Katen, Oregon

[hausdok]

Hi,

Here, carefully read pages 3 & 4 ref. corrosive chemicals and return air location.

http://www.docs.hvacpartners.com/idc/gr ... g8m-03.pdf

OT - OF!!!

M.

[hausdok]

Hi,

Here's the warranty. Check the exclusion for corrosive environments and DIY installs.

http://www.docs.hvacpartners.com/idc/gr ... 4dp338.pdf

By the way, these were available by going to the Payne site at http://www.payne.com

ONE TEAM - ONE FIGHT!!!

Mike

[inspect4u]

Thanks,

Now why didn't I think of payne.com?[:-banghea

Mike M

[Mogollon]

The UMC and the IMC prohibit pulling return air from a room that contains fuel burning equipment... or a closet,toilet room or kitchen.