Model 6500 HELP "Return Air"

[Polish Princess]

What is the "return air"?

I was told by USSC after they reviewed pictures of my installation I need a "back draft damper" (which they have the picture showing is installed) and "return air"

What needs to be done to have "return air" and what does it do?

Manual says outside air is not required but "return air make-up IS required." Is that where the filter goes?

I thought I saw someone had made an enclosure on the filter box. Was that on this forum? If so can someone please direct me to it?

 

[DexterDay]

Return air is a "Cold air return". The same as any regular forced air furnace. Return air, is just that, it returns the air from the living space back to the blower of the unit for re-distribution.
Outside air is the OAK (outside air kit) totally different that return air.

A backdraft damper is installed to prevent any air from the furnace you are tied into, from going through your pellet furnace or your existing furnace. You need 2 backdraft dampers if you are tied into an existing system. One for your stove, the other for the LP/oil/gas unit. This stops one, from back-feeding into the other.

Here are some examples to whats in my system. Still working on getting it tied into existing HVAC.

To get a real answer to your question. We need to know what your problem is? What is the issue you have, that US Stove responded to?

 

[Polish Princess]

Called USSC on November 11th explaining no heat. Customer service had me put my C-20 on 0 to bypass the pressure switch. Told me to call back was to report if had any flashing lights, errors or heat. I called and of course got voice mail, had no errors and no heat. During these several days I took the back panel off gave the whole furnace a THOROUGH cleaning and resealed everything. Reset my C-20 to 1 and upped my feed rate.Low and behold I have heat.

After several attempts to speak to the original customer service rep I repeated my situation to another rep. Was told to send pictures of my installation Finally tonight at 4:50pm I received a voice mail telling me after reviewing my installation pictures we need "back draft damper" Which we DO have one installed it is exactly like the one in your picture.

Was also told need "return air" I looked in the manual and this furnace does not require OAK but DOES require "return air make-up" I thought I saw on one of the forums a picture showing where someone had made and enclosure box covering where the filter goes.

 

[DexterDay]

If your stove is in the basement (probably) then the return air, would be another plenum and duct off the back pff the stove, that goes up into the living space (upstairs) and gets its air from there. The best way to do that would be to tie into your existing Cold Air return on your lp/gas/ oil furnace. This pulls warmer air from upstairs and recirculates it. Its colder than the outpitof your stove, so its a Cold Air return. Better than taking the colder air from your basement and trying to warm it.

Doubt it would have a great effect. But you wouldnt know unless you did it. My Fahrenheit says a Cold air return is not mandatory. Plus I am using a woodstove in the basement. So my air down there is about 85* . Much warmer than the air upstairs.

An OAK may be beneficial. But they specified a Cold air retun. Not a Outside air Kit. Unless there verbage is different, then I take it as a return for the stove. Nothing to do with the intake.

 

[Polish Princess]

Yes, furnace is in the basement.

You said best way is to tie into our existing Cold Air return on our electric furnace, do we need to have a box built to go over the opening where the filter goes? Then tie that into the cold air return? Will no longer need a filter?

The term the customer service used was "return air" she did not say "return air vent" just "return air" and the manual only says it IS required but no diagrams or description of how to be installed.

 

[SmokeyTheBear]

Return air is an indoor cold air return line, it provides the air that the convection fan forces through the hot air ducts. If a stove or furnace has a large enough air flow a sealed return air system is required, otherwise the blower can be subject to burn out.

Return air is to the convection blower as Outside air is to the combustion blower.

Filters are normally on the return air side.

 

[Polish Princess]

USSC manual says "return air" is required, but no where does it show what the installation should look like.

Any suggestions where to find this information?

Where the filter goes I have 2 blowers I guess that is why I thought would be the place to build a box and hook into my existing furnace. As you can read I am grasping for straws.

I have emailed USSC to have their techs send me a diagram so I can have installed, but if you have information it surely would be faster than me waiting for USSC. As this has been going on since November 11th

 

[SmokeyTheBear]

Please post a picture of where the filters are and check the area around that spot for indications of places for screws to be installed.

You also have to locate the cold air return on your other furnace as this is where you tap in to pick up the return air from the heated portion of the house.

When these two areas are hooked together the heated area of your house is in the convection blowers air path which is required for the furnace to have all of its installation requirements met.

 

[Polish Princess]

I looked on the back of furnace where the filter goes and NO place to install screws.

On page 11 of the Model 6500 manual it shows primary and secondary furnace when look at the primary furnace installation of the multi fuel it looks like the cold air return is attached to the back of the furnace on the bottom where the filter is but I am not sure.

 

[DexterDay]

This is a optional piece that must be bought through Fahrenheit. But it attaches to the back of the stove so it can accept a 10" cold air return line. My manual states you can connect into existing Cold air return, make your own, or not needed. Every manufacturer is different. But if they say its needed, then it goes somewhere.

Edit: forgot pics

 

[Polish Princess]

Page 11 of USSC Model 6500 diagram is so very vague. The only place the manual even mentions a "return air" is in the front.

USSC sent a diagram of one that is part UFB908 universal filter box. In looking at their diagram makes no sense it just looks like adding what it says a FILTER BOX which I don't need. My furnace has a spot for the filter.

They seem to be grasping for straws because I originally called them on November 11th because I wasn't getting any heat. I later was able to solve that problem but they said was because I don't have 'return air'. It put out heat last year just fine so this confuses me

Dexter, did that come with the Fahrenheit as part of the installation? What are the dimensions. The reason I am asking is in my above picture isn't much room. Would we have to push the furnace forward add the
box AND extend the exhaust pipe that comes out of the back of the furnace that is hooked to the flue? Then how is it tied into my electric furnace? Doesn't that also make any deep cleaning or maintenance that much more difficult.

What does this addition do and does it improve quality of heat?

 

[SmokeyTheBear]

This is how it goes that cold return air will cover the filter area (likely by using self taping sheet metal screws) and allow you to connect to the existing hot air systems cold air return. That is all it does from a heating system point of view. Back flow dampers should be considered to completely isolate your currently unused system.

The impact of not having the convection air system setup that way varies depending upon the convection blower in the stove. A lot of convection blowers in hot air furnaces can not operate for long in free air, they burn out.

The other thing a fully sealed air system will do is stop you from sucking basement air through and out into the living areas of your house.

The lack of room behind the stove can be corrected.

 

[Polish Princess]

Isn't the pic I have a back flow damper? I think it is.

I am confused what do you mean hot air furnace? We have an electric furnace is that the same? It is only a backup and for air conditioning, we do not use it when using the Model 6500 Pellet. Our Pellet furnace is our only source of heat when we need heat.

Also, why should I be concerned about sucking basement air?

 

[jtakeman]

What they want you to have is a closed loop system. Sucking the basement air in turn sucks the heated upstairs air down to the basement, So you are also heating the basement area. You'll also take longer to turn the house air over, Because you have added the area of the basement to the total volume of air you want to heat. Adding the return air from up stairs eleminates the basement air volume. Less air to heat in total. Your heating less air volume so it should reduce the heating costs somewhat. The stove should radiate enough heat to warm the basement or at least keep it above freezing temps.

Hot air furnace or forced air. A system that has a (oil/gas/electric)heat source and A fan forces the air across the heat source and distrubutes it through ducting.

 

[SmokeyTheBear]

If you have air ducts on your old heating system it is a hot air system regardless of what you use to provide the BTUs, pellets, corn, oil, gas, coal, electricity it all is creating hot air.

You need to be able to close off both sides of the air flow, that is why back draft dampers are always in pairs.

You close off the unit that you aren't going to run to stop the heated air from loosing heat inside the other device through its heat exchangers, etc ...

 

[Polish Princess]

J-

But I like having my basement heated as I have my laundry room, sewing room down there .

So is this contraption still necessary? Or is it just something they told me to do to shut me up.
Again my original question to them on November 11th was low heat output but I adjusted some things and have the temp I want.

I KNOW in reading hundreds of posts on this site I saw a picture of a triangular box someone had put on the back of their furnace where the filter goes. Can someone point to the post or
have I just stressed over this too much and dreamed it?

Smokey

I have ONE back draft damper the goes to my electric furnace and it is CLOSED during the time we burn pellets. Am I supposed to have another and where does it go? Again page 11 of the 6500 Manual doesn't show what I keep asking USSC.

 

[jtakeman]

That is the same thing dexterday posted in post 9. I remember seeing it too. So you where not dreaming. I think it was chriswny's showed while installing his Fahrenheit furnace.

I'll try and find the link to it.

https://www.hearth.com/econtent/index.php/forums/viewthread/67125/P0/

Pretty much yes, Thats what US Stove wants you to install. But if you want the area heated to about the same temp as the upstairs? Then no you don't need it. But you will have to pay to heat that area.

 

[DexterDay]

The Return box was an extra item for the Fahrenheit. It is 20" wide x 12" tall x 12" deep ( with a slight angle cut on the back)

If they say its mandatory, then it should be installed (Cold air Return)

If they say they recommend it, then its not necessary.

If its not necessary and you are getting the temp you want, both upstairs and downstairs, then run without it. Although you will use a lot more pellets to keep the upstairs at 70*, compared to not heating the basement also.

I am going to be running a woodstove in tandem with my Furnace. So the air temp in the basement will be hotter than upstairs. Its hard to get the heat up there. So I am going to use the furnace to pull the hot air from the basement and distribute it upstairs. That will set-up a good convective loop. Or so I hope.

 

[SmokeyTheBear]

J-

But I like having my basement heated as I have my laundry room, sewing room down there .

So is this contraption still necessary? Or is it just something they told me to do to shut me up.
Again my original question to them on November 11th was low heat output but I adjusted some things and have the temp I want.

I KNOW in reading hundreds of posts on this site I saw a picture of a triangular box someone had put on the back of their furnace where the filter goes. Can someone point to the post or
have I just stressed over this too much and dreamed it?

Smokey

I have ONE back draft damper the goes to my electric furnace and it is CLOSED during the time we burn pellets. Am I supposed to have another and where does it go? Again page 11 of the 6500 Manual doesn't show what I keep asking USSC.

Normal sistering of a hot air systems requires a means to block both the cold air and the hot air side of things.

Personally I don't care what anyone might want to do.

I want what ever is done to operate properly and be safe.

If the manual says must have, then it must be provided. I'm not going to debate shades of gray if the manual says there is no gray. Now I haven't read the manual for your unit since the last time we chatted.

I also don't care why USSC is saying what they are.

I do know that depending upon the convection blower in that furnace you could be headed for premature blower motor burn out and that sucking in basement air can lead to other problems in the livable portion of the house.

 

[Polish Princess]

This taken directly from my manual on page of SAFETY PRECAUTIONS


"Use of outside air is not required for this unit. However, fresh air and return air make-up is required for maximum burn characteristics and heat distribution throughout your house."

My argument with USSC is I DO have fresh air and my question is WHY are they wanting me to BLOCK my filter area?

 

[jtakeman]

So I am going to use the furnace to pull the hot air from the basement and distribute it upstairs. That will set-up a good convective loop. Or so I hope.

Once the ducts warm up, You'll be surprised how good it actually works. If I ever run out of pellets and have to burn wood. You can bet I'll have the fan on the Omega rigged to be my ciculator of heated basement air.

 

[SmokeyTheBear]

This taken directly from my manual on page of SAFETY PRECAUTIONS


"Use of outside air is not required for this unit. However, fresh air and return air make-up is required for maximum burn characteristics and heat distribution throughout your house."

My argument with USSC is I DO have fresh air and my question is WHY are they wanting me to BLOCK my filter area?

They are not telling you to block the filter area, they are telling you to connect that filter area to the cold air return on your hot air system.

 

[DexterDay]

Return air, does not block the filter. The housing goes on the back of the stove and then more duct work comes off of it. Im gonna take another pic for you

 

[DexterDay]

The adapter that goes on the back of the furnace accepts 10" duct (for mine anyways). It is then ducted in your existing cold air return for your electric furnace.

You electric furnace should have a filter on it. The area "Before" the filter (just like on the Pellet furnace) is the return duct. Without a return on your electric furnace, it would just be a filter too.

1st pic is the pellet furnace. Duct on right is heat duct, duct on left (back side) is the return air, the adapter screws to the unit and the filter still has a slot to slide in and out. The return air comes in through the duct, through the filter, then through the firebox and heat exchange tubes, then finally back out the front duct.

2nd pic shows my LP furnace (Trane XV90) cold air return is on the left side, filters go in at the bottom, just before the furnace, then the hot air duct is on top pf the furnace. The systems are the same, one uses pellets, the other gas. But overall, the same components in the duct work are needed.

 

[Polish Princess]

OMG thank you to both of you I FINALLY feel like someone is helping me understand what USSC has been unable to explain.