Garage furnace

[Tom7227]

I am toying with the idea of getting a ceiling mounted furnace for the garage. 23 x 33 with a flat insulated ceiling. Just getting started with the research. Northern has one for $470 HeatSstar by Geneco. Any input on the maks/model? It can be vented through the wall. I have a wood burner that I don't use and it has a 6 inch insulated pipe but it sits about 18 inches from the ceiling. If I were to go with the gas unit I am wondering if I could use this furnace and the existing pipe, which would mean that I would be pushing the exhaust down and then out. I thing this would work if the flue was a power flue on a high efficiency furnace that you can vent with PVC, but I doubt it would work on a gravity system. Does anyone have any experience with these types of units and know whether it would work for my setup?

Frankly I would be very satisfied with a used house furnace that I could tuck in a corner on a stand. I probably wouldn't even bother with any plenum or duct work but I don't know any heating guys that might run into one while replacing a house furnace.

Thanks for your time.

Tom

[Eelpout08]

Personally i would go with a reznor or modine, modine being my first choice. I have heard quite a few stories of the cheaper ones costing more money in the long run due to parts failing.

As far as the flue, you will have to follow the manufacturer's reccomendations, but generally they want the flue pitched back to the furnace.

Also i would guess that the flue should be 'class B vent'(Aluminum inner wall, galvanized outer), probably 4" diameter, with an approved termination cap and wall penetration.

I would be careful about using a bigger flue, as the pressure sensors on the furnace may not work properly, among other things.

[CAMAN]

Frankly I would be very satisfied with a used house furnace that I could tuck in a corner on a stand. I probably wouldn't even bother with any plenum or duct work but I don't know any heating guys that might run into one while replacing a house furnace.

Check the "list".

[Eric Wettschreck]

You don't want your flue gas going downward. It should raise from the heating unit through the ceiling or wall.

If it were my money I'd install a Hot Dawg unit. I've recently installed a couple of them in one of our warehouse buildings and they're nice little units.

[DRH1175]

I have the HeatStar unit in my garage. It is a great heater. I have had it for 5 years now and I have been very happy. Don't mess around with the old vent. Just use new 4" class b vent. You can get that and a wall thimble at the big M store. With this heater you can do horizontal pipe thru the wall, as it has a power exaust fan. You actually want a very slight down angle towards outside or a Tee to stop condensation from running into the Heater. The Modine and Reznors may be a tad better of heaters, but they were quite a bit more expensive when I bought mine. Like $700. The Heatstar is a good garage heater.

[Tom7227]

I checked as Caman suggested and I am leaning towards a 80kBTU house furnace. I have about 40 feet to go from existing gas lines to the new spot. Should I go with 1/2 or 3/4 steel pipe?

[BoxMN]

Tom, just a suggestion, but if you are buying a house furnace (instead of getting freebie from buddy in heating...) maybe consider a new higher efficieny for your house, and put your house furnace in the garage. That is what I did about 6 years ago. Has worked great. I did have a buddy make a plenum for me, as he said it still needs correct pressure, even if you don't duct it anywhere. Good luck, you will love it!

[CAMAN]

I agree with BoxMN with upgrading the home furnace if possible. Also, yes the furnace needs correct back pressure to run efficiently. Even if it is just a plenum like Box did, but me personally, I would try and hang the furnace from the ceiling and run a single run across the ceiling putting registers where needed, just make sure they aren't blowing directly into the prime work areas, that would just make you cold and dry your eyes. I'd imagine a duct guy could do this for fairly cheap.

[Redlantern]

Tom, are you using Natural Gas or Propane? What's the pressure? Need to know this before someone can tell you the correct sizing of the pipe.

[LightningBG]

For what its worth.

That Heatstar from northern runs 469+tax for 45K BTU

Online at Alpine Home Air they are selling the Modine Hot Dawg (45K BTU) for $691 with free shipping and I'm guessing no tax.

(I haven't looked anywhere else to see if there are cheaper out there)

[Tom7227]

House furnace is too new to replace. Gas pressure is whatever the gas pressure is, don't know how or have the tools to check. It is natural gas.

I guess I don't understand the pressure thing with the hot air outlet. The unit I am focusing on does not have any plenum on it. They guy said he could make one for me as he is an installer. No chance for duct work as the ceiling is only 7 feet up. The garage was an add on and has a cement beam ceiling and the top of that needed to match the first floor of the house. The garage is at basement level and not dug down far enough, likely because of ground water. I haven't taken on the task of jacking the house up along with the garage ceiling so I have to make do with what's here.

Thanks for the input. I think it is going to be 3/4 black steel. Heavy gauge copper flex might work but I don't like that idea for a shop area. Just an old fashioned hardware guy I guess.

[WallEYES]

Tom

If your on a high pressure system you can run 3/8 i.d.(1/2 o.d.)soft copper. install before the regulator in the house staying on the high pressure side and then install regulator on the garage furnace

[WallEYES]

Also your garage furnace must be 18 inches off the floor from any source of ignition including any wiring within the unit and burner assembly.

[Tom7227]

Also your garage furnace must be 18 inches off the floor from any source of ignition including any wiring within the unit and burner assembly.

Thanks for the reminder. I suspect that you mean any source of ignition must be 18 inches off the floor.

[Tom7227]

I ended up with a Ruud Silhouette II Plus 2 LXF. I can't find a manual on line. It has a power vent motor and so I am wondering if I can vent it with ABS or if I should go with tin. There is a cap on the unit that increases the opening to 4 inch.

Again, thanks for your help.

Tom

[Smoker]

Still needs to be Class B pipe going through the wall. Here we can run single wall alum. pipe up to that. You can not use ABS pipe.

[Eelpout08]

I will second running high pressure gas to the furnace and using a regulator at the furnace. There are charts that will tell you how how much gas you can get thru a certain dia. pipe at a certain length. When i can find mine i will take a look. Also your current regulator will most likely not have enough capacity to handle another 85k btu thru it.

[Tom7227]

Pout,

It's done. It fires up and makes the garage warm.

I don't know anything about the pressure thing. There's a regulator on the meter outside and that's it.

I would be extremely reluctant to start screwing around with the one outside, in fact I'll just say I won't do it. Since everything is working then maybe all is well and I should just let it be. Blissfully ignorant but warm.

Tom