Furnace install advice needed

[xrdad]

After much time spent believing a new Mr. Heater would go into my shop, a deal I couldn't pass up came my way and now I'll be attempting to install a used NG furnace in the garage.

I did a search and found that many have gone this route and most seem satisfied with the results. I'm hoping for the same! But, I could use a little help in the planning part.

If any of you with experience could guide me, I'd very much appreciate it.


Here's what I've got and know so far.
It's a York Diamond 80. Supposedly, it ran fine and was only replaced because the owner needed to upgrade to qualify for a rebate on some home renovations.
The serial # is ELJM491816. I couldn't find a tag with model #?
So now I'm trying to figure out how to get an installation manual... without the model #, might not be easy. I'm hoping someone here recognizes the unit or can tell me where to find the # so I can try to find a book.
Or, is a furnace installation somewhat generic?

The ideal plan would be to hang this unit near ceiling height (15' in my case). It is a downdraft model. I've already had the gas line run to the garage for this purpose. I also already cut a 4" hole in the side wall, about 4' below the soffit. The edge of the roof doesn't stick out a whole lot, less then 20" for sure.
The shop is 20x20 and 15' tall, is insulated (doors too). It's still a work in progress, but will be used for general auto repairs for the most part. If I'm painting/woodworking, the doors will be open.

Not sure if this is enough info to start, so just ask and I'll try to find out more.
Thanks!

 

[Falcon67]

There should be a tag somewhere with the model #. That would at least get you - maybe - some install instructions. It'll have the BTU info and other pertinent info on it. Or, look at similar models from Goodman, etc and use their install manual. Generally, if you know which way the air flows, where to mount the filter and how to wire and plumb it it's all about the same.

We have two systems in our Data Center, both home type units. One it hung from the ceiling with a filter mount in the back and a little bit of sheet metal ducting on the other end. The other is an 5 ton downflow - it has the filter mount on top, sits on a plywood box/plenum with an insulated box extending out the side with vents in it. Very hacked together by maintenance, works fine. Will freeze your ankles off.

 

[rickairmedic]

XRdad the model number on your furnace is " P4DNA12N06401A " it is a 65,000 BTU furnace with a 3 ton blower in it . The bad news is it is a downflow model which means it can only be mounted in a downflow position . This means the incoming air has to go in the top and the outflow " heat " has to come out the bottom . This furnace cant be mounted on its side .

The basic install otherwise is prety much universal . I would make a box for it to sit on with a large vent on the front of it and a metal top for it to sit on . Otherwise the electric and gas hookups are going to be the same as any other furnace .


Rick

 

[xrdad]

Wow Rick, thanks!
Where the heck did you get the model # from the info I had??!!!

Anyway, no bad news!! I hadn't intended on mounting it sideways (honestly, because I didn't even know that was an option with some )..

The plan is to hoist it up to the ceiling and let it blow air down into the shop.

So, with a model #, now I have to find an install manual. I need to know how big a plenum this will require to work properly, does it need duct work out the bottom to work correctly or more efficiently, and finally what maintenance I should be doing before hanging it.

I still don't know if this is a condensing unit? Also, the wheels are turning and I'm wondering how I could use it to move air in the summer time (no a/C)...

Thanks again guys!!

 

[rickairmedic]

xrdad I can tell you it isnt a condensing unit . The pipe sticking out of the top of it is metal that coupled with the 80 in the name tells me it is an 80% furnace . I took your serial number and called my local York distributor and they gave me the model number . They didnt have alot of info on it other than it was most likely an early 80's built unit . As far as ductwork on a 65,000 BTU unit I would go with an 8" X 24" main trunk line running front to back in the garage with vents cut into it along the way . You dont really need any ductwork if your hanging it up high but it would help distribute heat throughout the garage . To move air in the summer simply install a standard heat and air thermostat and run a 4 wire thermostat wire which will have a red wire ( 24 volts hot ) white wire ( heat ) green wire ( fan ) and yellow wire ( ac ) which you wont use . The grenn wire lets you use the auto / on switch on the thermostat to run the fan only .The manual on the furnace wont tell you much other than hooking up the Tstat wires which is pretty universal .


Rick

 

[xrdad]

I would go with an 8" X 24" main trunk line running front to back in the garage with vents cut into it along the way . You dont really need any ductwork if your hanging it up high but it would help distribute heat throughout the garage . Rick

Really, thanks for taking the time to find out for me!
I suspected the metal out pipe meant it would be non condensing, which in my case is a good thing.

I hope my questions aren't going to be annoying, but I got a confused in the ductwork answer. I think you're telling me what duct to run on the outlet/heat side (under the unit), but what about the inlet? Do I need a plenum?
Or can I just build a neat filter rig right on top

How much space would you recommend between the unit and the ceiling? I may have already decided that since my exhaust outlet is 4' below the ceiling, so my exhaust must be almost strait out at that point.. obviously can't install the unit higher than the exhaust port.

As far as running the fan in the summer, my thoughts exactly and I'll not need ceiling fans now.. wondering if I can McGyver something to pull cooler outside air in from outside

 

[rickairmedic]

No problem on the questions . This is one of the few areas I can give back to the board on . Yes the ductwork I was speaking of would be under ( heat side ) the unit . As far as the intake air a simple filter rack right ontop of the unit would be fine most likely a 16X25 filter for that unit .

You have already set the height of the unit by drilling the hole through the side of the building as it needs to be below that hole to vent out the bad gasses properly .

The last furnace I put in a buddies garage we simply built a box on the supply" heat " side of the furnace the same size as the outlet and about 12" tall and ran round ducts off of it one to each corner of the garage and one pretty much right over where he would be standing while working under the hood of a car . I would go with 6" round duct pipe in this application .

You will need double wall vent pipe for the flue pipe going out the wall ( you can use up to 3' of songlewall pipe comming out of the furnace itself then must transition over to doublewall pipe . You will also need a wall thimble for the pipe to pass through going through the wall which means your 4" hole will get bigger up to 6" I for the thimble which will give you 1" clearance around the pipe itself going out the wall .


Rick

 

[xrdad]

Great!

I do appreciate the time and info Rick.

I found this for the inlet side (attached) and with the info you gave, I'm ready to start.
I'll have to dig a bit to figure out what the vent outside the garage will look like, but that shouldn't be too hard to figure out. Going to Home D tonight to pick up some supplies!!

Thanks!

 

[xrdad]

bah... the jpg is too small!

 

[rickairmedic]

I can see the jpg and you dont need to go to that much trouble for the filter honestly looking back at your pictures it looks like there is already a filter rack of sorts ontop of your unit . I might suggest covering the hole you put in the wall and just going out through the roof with your vent pipe as it will allow you to put the unit higher up in the ceiling . The one I did for my buddy was an upflow type of furnace so we were able to lay it on its side on the rafters but yours will have to go in standing up so the higher you can get it the better options you will have on running ductwork ( without extra work ) .


Rick

 

[xrdad]

Yeah, I'll seriously consider 're purposing the hole I made and going through the roof. There were other threads on here that talked about under soffit exhaust issues and such, + how low will I be when I'm done?

I'll measure and photograph tonight and give you my plan of attack.

 

[HVAC Phil]

If you vent it out the sidewall, vent must 90 up on the outside. The rust running down the outside wall from fluepipe won't look good as this furnace is not approved for sidewall venting.

 

[xrdad]

Thanks Phil.. didn't think of that and now I'm certain I have to go through the roof.

Here's some pics I took last night to give you a better idea, but in the end, the job is pretty much figured out now... just have to pick the best location.

Thanks for your help guys and Rick, you called the model # correctly.. had I looked just a little longer, I would have found it myself. It was on a tag on the side cover, near the front door.

In the pics, the 2 garage doors are the front, the tool box and door are the back, the wall with the bolt bin is the outside (and the existing hole to outside is just above the whipper snipper hanging there) and finally the man door leads into the house.
.... yes, it's almost 5' off the floor. Not planned that way and still trying to wrap my head around how I'm going to finish this space.
As stated earlier, 15' ceilings/8' insulated doors with high lift installed taking them right to the ceiling. The shop is insulated on 3 of the walls right now with R20, R40 in the ceiling.

So, now I'll hit the Home D to figure out what I need to run the exhaust through the insulation/roof.

My last question: How would you hang the furnace? I'm thinking of making a 'craddle' out of angle iron I have (bed frame) and bolting it to the trusses?
OR??!! what about installing the funace IN the space above the garage, between the trusses???

BTW, don't mind the mess in the shop.. we moved in this past Sept and it's very much a work in progress that has priority LOW... wife says the inside of the house gets done first.

 

[Mmfh]

One thing I can tell you from my last install, it was that exact furnace, not that it really matters. Getting your supply ductwork dialed in is important for it to work its best.

When I first hooked up mine, I had only two large vents to heat the shop. The air movement was too fast and didn't heat up enough while it was passing through the furnace.

I found I needed to slow down the air, give it more time inside the furnace to heat up before blowing it into the shop. I added 6 vents, put regular registers like you would see on the floor of a house, that slowed it down so it put out some real heat.

Let me tell you what, if it was 20 degrees outside when I went out to the shop, turn on the furnace, 15 minutes later it was 70! That thing would cook you out of there in a short amount of time.

If you find it doesn't seem to work as you think it should, think about the time the air is in the furnace and heating up before blowing into the shop.

I don't remember on that unit, but many furnaces have dip switches that you can change to change the fan speed. Control the supply temp that way.

Mm

 

[rickairmedic]

Ok heres my next question . How much room do you have in the attic space ? With garage doors on the front and back of the garage and high lift tracks your not going to have much room below the ceiling to run ductwork . With this in mind if there is enough room in the attic I would build a box for both ends of the furnace . Then for a garage I would hook a 20" flex duct to the incoming air side and run it over to a hinged filter grill in the ceiling thus taking care of your filter needs . Then I would run 6" flex ducts off of the outgoing side box . I would put 2 vents in the ceiling above the front doors and 2 on the back wall . Then one on the side near the house and one or 2 on the wall away from the house . You want the return near the center of the garage ceiling .


As far as hanging goes I am a big fan of unistrut and threaded rod as thats what I have always used to hang furnaces .


Rick

 

[xrdad]

Can I stop saying thanks in every post now?
Let's just assume that I appreciate everyone's help

There is lots and lots of room over in the attic. It does have engineered trusses and blown in insulation though, but I doubt my 60lbs furnace would be much of an issue if a span it over a couple of the beams by making a shelf for it to sit on.

I really like the idea of hiding it up in the attic with the vents coming down over the doors and walls. With the one unfinished wall, I could even bring 2 runs down just above the floor? The dimensions you gave will help me out a lot!! and the advice on slowing down the air is perfect..

Here's a couple more pics to help...

Before I go to far and change the plans, my next thread will be for help designing a loft at the back part (above single door) of the shop. Think of it as a 20' wide 8' deep shelf. I don't think this makes a difference for 'our' heating plan

 

[rickairmedic]

Oh yeah you have plenty of room up there for the furnace .


Rick

 

[pstnbly]

Call me an old lady, but a 30 year old forced air funace that was taken out of service really needs to have the heat exchanger inspected thoroughly. 30 years is over the life expectancy and a cracked exchanger can lead to CO poisoning. Be sure you know what you are installing

 

[mrobins297aaa]

Only draw back about putting it in the attic is service, so think about that and also make sure you have enough combustion air up there, you probably do but if some how that attic space is not open to the rest of the house you could have a problem.

 

[xrdad]

Not an old lady... thanks for the reminder.
Yes, I'll have the unit inspected before I even attempt to get this installed. I do have a friend that will help me (HVAC tech). He doesn't chat on forums and is really busy, but when I'm ready he'll take the take to come see.

If this unit is 30 years old, it sure doesn't look it!

Service will be a royal pain, but I'll make sure the attic access is good and the unit will be built up on a table/shelf in there with lights.

Combustion air shouldn't be an issue.. the attic is open right across the entire home. It's better than 10' high in the center over a 1400sq ft house.

So next step is duct work.

Any concerns with pulling air into the unit from the garage floor (18" above)? I can leave the space between the wall studs empty and use that cavity to pull air in.

For heated air: metal ducts in the attic or flexible?

 

[rickairmedic]

I am going to guess the air you are talking about puling from the wall is the " return air " or cold air going back to the unit . You could certainly pull it from the wall space . You wil have to pan in and box in the ceiling joists above the wall cavity though so that it is sealed . Then in your situation I would run a 20" flex duct from the boxed in ceiling joists to a box ontop of the unit . The supply " heated " air I would build a metal box for the unit to sit on and run flex duct 6" from it to your registers .

Rick

 

[xrdad]

Sold!

Thanks Rick.. that's exactly what I'll do.

All that left to do is photograph the process and let you know if it all works

I might even start this weekend!
Hmmmm, how the hell am I going to lift that furnace into the ceiling! Trip to the rent all and see what they've got.

 

[xrdad]

Furnace is still sitting on the floor.. change of plans, then another and finally another.

The furnace is going to be installed - yes.
in the attic - no.

I'm going to mount it on the wall and I'm curious... is there a clearance spec for a furnace?
I mean, can I install it with one side 'touching' the wall?

 

[HVAC Phil]

Furnace is still sitting on the floor.. change of plans, then another and finally another.

The furnace is going to be installed - yes.
in the attic - no.

I'm going to mount it on the wall and I'm curious... is there a clearance spec for a furnace?
I mean, can I install it with one side 'touching' the wall?

Usually you need 1" clearance, sides and back, 24" front for servicing.