Gas heater choices for workshop

dbelisle · Oct 22, 2004

I have installed many Reznor and Modine Hot dawg units. They do a great job.

They are up high and out of the way. Some of the units are sealed combustion so your not using any of the air your trying to heat for combustion.

You have to be careful in a garage as the codes don't allow anything that could be a source of ignition for vapors below 18 inches off the floor.

I can't tell you how many times I have gone into a garage and seen a warn air furnace sitting on the floor.

I will not install unvented units for people. Most of them will work fine. But there is always a chance one will malfuction and I don't want the liability. Even in a good working unit, the by product of combustion is CO2 and water vapor. It will produce 11 gallons of water for every 1,000,000 BTU used.

That is a lot of moisture where you might not want it.

Dave in NH

PeterT · Oct 22, 2004

Dave

would one of the sealed combustion units be safer in a woodworking shop where there is a lot of dust in the air, more so than a non sealed unit?

I have a reznor now an have wondered about all the dust in the air causing an explosion. /forums/images/graemlins/frown.gif

Good luck PeterT

MarkLeininger · Oct 23, 2004

Yes, there were several comments in this thread about that. I've been told that it's "very dangerous". I'm still considering a forced air electric unit. They're cheaper and my location is right next to the service panel, so it's easy to put in a line for it. They are quite a bit more to run around here because gas is relatively cheap. We had a sealed combustion unit in a building we owned and it did not hold up well; pulling in freezing air causes condensation in lots of places so you have to make things out of corrosion resistant materials, etc. I'm sure they've solved those problems now, that was back when they first came out and were so efficient it would save enough to pay for themselves in 5 years. Except in five years they were junk.

thcri · Oct 24, 2004

Reznor does make a sealed combustion unit. Very expensive but would be the better choice for you. If you wish I could get some literature on it for you. Just send me a PM.

murph

MarkLeininger · Oct 24, 2004

Found the info on the web. I think the combination of cost and my not so great experience with sealed combustion is tipping me towards an electric unit with a fan.
Thanks for the offer.

dbelisle · Oct 24, 2004

The worst place I ever installed a sealed combustion unit was in a flock mill . That is a very dusty place and flock burns.

The unit worked fine and they didn't have to worry about the flock getting into the combustion area and starting a fire.
The unit that I replaced was not sealed combustion and they did have problems with fires and keeping the unit going as the flock would get sucked up into the burner.

They still had to blow the unit out every so often as material would build up on the outside of the heat exchanger and blower.

But with sealed combustion all your makup air for combustion is coming from the outside so vapors or dust in the room are not effect the operation of the burner.

The other nice thing about sealed combustion is if you turn any fans to vent any dust and vapors from the room, it doesn't have any effect on the barametric pressure in the combustion chamber and that has a big effect on how the unit will run.

If I had to have a unit in a wood shop it would be sealed combustion.

Dave in NH