Sealed Garage Heater

[Denver Woody]

I'm looking for a natural gas, sealed combustion, forced air garage heater for my 20' X 20' insulated garage workshop (which also has to house our two cars). From my research so far I can only find a Reznor unit that meets the above specifications. From what I can tell the Modine Hot Dawg units do not have sealed combustion chambers. I have already decided that I want a sealed unit and also that I don't want radiant heat. One contractor that has come to my house gave me an estimate of around $2000 to install even the

30,000 Btu Reznor sealed unit (which apparently is about the right size for my installation). I wasn't under the impression that Reznor would sell direct to customers, but I would certainly consider self-installation, as my brother-in-law is an electrical contractor and has a "gas guy" that would do the natural gas work for only the cost of materials. I'm a little concerned, though, about making sure the whole installation is to code and safe. My questions are...

• Are there any other brands other than Reznor that provide the type of unit I'm looking for?

• Is there a place where I could buy one of these heaters direct?

• Would the installation and especially the venting be a difficult thing to get right?

Thanks, DW

[BRuce]

it is not rocket science but does have to be done right. I would check with the local inspector (assuming you are going to get it inspected) and see if he has specifice requirement. they may actually have a spec sheet that will give you THEIR clearence requirement and slops and all that.

As for the heater, I can't help you their, I just have a none vented propane unit.

BRuce

Denver Woody wrote:

[Joe Froedy]

You might check

to see if they have a unit similar to what you are looking for.

[Rumpty]

direct vent propane will work.

[Denver Woody]

It looks like their "unit heaters" are from a company called Dayton, which I had not heard of. From what is displayed in the Grainger catalog (limited information), it does not seem to me that these heaters are sealed unit heaters. I tried to Google for "Dayton heaters" and several variations, but I could find no company homepage to give me more information.

Thanks, DW

[Edwin Pawlowski]

Dayton is the house brand for Grainger. Sort of the Kenmore of Sears.

[Robert Bonomi]

Dayton Corp. *LONG*TIME* manufacturer of fans, blowers, etc.

They seem to be a division of 'somebody else' these days. No luck finding a corp site for 'em, either.

[Rob Stokes]

I looked at the same thing for my 20x20 shop and ended up with the Reznor FT

1. Nope, it's not a sealed unit but I did get the stainless steel heat exchanger as I figured the unit may undergo condensing at night when I turned the heat down. Initially I wanted a sealed unit but was talked out of it by the rep and by several engineers. The theory being that the volume of dust in the air to even begin thinking about an explosion would mean that the place would not be habitable to begin with. Keep in mind that the rep actually "down sold" me and lost a larger sale because of this.

I hung the unit myself with a little help from a "gas guy". The elec was a simple 110VAC feed and a pair of thermostat wires. The worst part was lining up the vent with the back of the unit when I cut the hole in the wall. I ran the unit for the time I was in the shop (have since sold it) and I know it's still running now and being used every day.

$2000 is too much money. you should be able to do it for 1/3 to 1/2 that.

Good luck Rob

[Denver Woody]

So that opens up the possibility of running one of those Hot Dawg units as well (if a sealed unit is not all that necessary). I don't know if they're any lower cost than the Reznor units. I get the impression in my research that Reznor commands a premium price. Did you ever stain or polyurethane in your garage or have the concern of igniting those vapors?

Thanks, DW

self-installation,

variations,

[Brian Rosenthal]

I have a Reznor; it uses a co-axial flue to get cold combustion air in and exhaust out. Mine is vented out the side of my garage instead of going up. Since moisture is a by-product of combustion and the exhaust tube is surrounded by a cold air coming in, the water tends to condense on inside of the exhaust flue and run downhill. Initially that meant back into my house and into a storage shelf!

The heating company made good and fixed it, now the chimney tubes are all sealed with high temperature caulk and the inner tube is tilted slightly so the water runs out of the house. I often have a 4 to 6 foot ice stalagtite under my heater's exhaust. If you have one of these units installed, make sure you know where the water will go.

-Brian Rosenthal

[Denver Woody]

I didn't realize how much more the sealed units would be over the non-sealed types. Do you think that the airborne wood dust, or stain or polyurethane present a flammable hazard? I'm starting to wonder myself...

Thanks, DW

[Frank K.]

I've had a 45,000 BTU propane Hot Dawg in my shop for almost two years with no problem. As someone else suggested, the air quality would have to be uninhabitable before the heater exhaust becomes a concern. The cost of my heater with installation and shipping was about $550. I installed the heater and the propane company installed their tank, lines and fittings. I bought my heater from

All the info you need is available at the site. I ordered on a Thursday and it arrived the following Tuesday. I bought the thermostat, type B vent pipe and cap locally. I vented out a side wall rather than going up.

If you have further questions, email me. I can send you photos if you would like.

Frank

[BRuce]

I stain what I term as small items, up to half a sheet of plywood, in my shop with a non vented propane heater. there is not enough solvent in the air for an ignition. In order to do larger pieces, or poly, I move to the garage (unheated). the major problem being space and the air would not be breathable in the shop for days after. My shop is fairly tight to help with the heat and AC so i try and poly outside of it.

If you are going to vent the shop properly, to finish in there, then you will exhaust all the solvent (along with the heat) so it wouldn't matter.

BRuce

Denver Woody wrote:

[BRuce]

I would hazard a guess that most of the regular posters here do not have a sealed unit. The concentration of either dust or solvent has to be fairly high before there will be a problem. I am guessing that you would not be able to be in the shop at those levels.

I expect that there will be a huge posting by someone with a story about a friend of a cousin that made 3 cuts on his table saw and the heater cut on and the whole place burned down but I really doubt those stories. Falls into the same category as grounding your PVC dust collection pipe (don't start that here! email me directly).

I use an unvented heater and there are many postings ranting about not doing that because of all the water vapor generated and your tools will rust in hours. Well I do get some rust on my tools, year round, I'm in the south and the humidity is always high, that's just life.

I've been reading this and other news groups for a long time (back when we go them via UUCP!) and the best advice I can give you is to look at the postings, throw out the ones that say "you HAVE to do it this way", the ones that say "you CAN't do it that way" and look for the folks in between.

BRuce

Denver Woody wrote:

[j]

Are sealed combustion and direct vent the same, similar or...?

jw

[Brian Rosenthal]

I'm not sure. Most of what I use is water-based; it just fell into the "it seems like a good idea" type choices.

-Brian Rosenthal

[Woodstock]

I bought Reznor 45,000 BTU sealed unit for my shop, having also looked at the Hot Dawg. The heater itself was around $1k from the distributor and installation and chimney and other parts added close to another $1k. Like you say, the Reznor model in question has sealed combustion and takes its combustion air from outside via a pipe, not the shop. The Hot Dawg is not sealed and takes its combustion air from the surrounding space. Both of them pipe their exhaust products to the outside.

Even though the Hot Dawg is much cheaper and seems to have lots of sastified users, I still went with the sealed Reznor, based on advice from the local distributor (who sells both types) and reading the product literature closely.

First, the sealed Reznor unit is specifically designed and warranteed to operate trouble-free in dusty woodworking shop conditions. The Hot Dawg is marketed and warranteed as a garage heater. Obviously, both these heaters work by blowing large amounts of (more or less dusty) room air across a heat exchanger then back out into the shop. Given how complex the burners and sensors and electronics located in the same cabinet look to be, it seems reasonable that a sealed combustion system should hold up better over the long haul. Second, the Hot Dawg has certain ventilation requirements for use in some confined, tightly built spaces that do not apply to the Reznor which takes its combustion air from outside.

...If you haven't already, download the full installation and owners manual for both units (not just the consumer brochures or spec sheets). IIRC, both address these points in detail, includuing the presence of dust and wood dust as operational and/or warranty issues or non-issues.

Whatever you go with, I think you will be very pleased with how well these heaters work. Being able to walk in and crank the thermostat to any temperature you want and have a toasty shop makes a huge difference.

[Denver Woody]

Thanks for the detailed response. I think the key to satisfaction with the Hot Dawg may be to keep my garage dust-free, which is difficult when I've already got a ton of mobile-base-equipped tools and two compact cars in there. Fitting something for dust collection will require some ingenuity.

Thanks, DW