dust and my furnace (Update 2)

[Larry Levinson]

am in desperate need for advice about my basement woodshop and the furnace/central air unit. we share the same space, with no separation. the local utility guy just told me on the phone that my options are as follows, or I will kill the unit ...

1) Turn off the unit while working (freeze the family.) at the end of the session, open the front, vacuum it out and the area immediately around it before turning it back on.

2) Box in the unit and figure out someway to supply air.

a) new outside air supply? sounds expensive. b) louvered opening in the ``wall'' that backs on to the laundry room? (lint issues, but obviously much less than sawdust.) c) cut the access door, with louvers, in the laundry room wall, which would elimate the workspace used by SWMBO for her jewelry hobby.

what do all you guys do about this?

REALLY want to avoid having to move to the garage ...

UPDATE: I currently have a Jet 650 CFM dust collector with two diverters to handle tablesaw, router, jointer and planer, plus an air cleaner that I built from the American Woodworker plans a few years ago.

UPDATE 2: anyone in the Trenton area want to go in on an office/warehouse lease with me? there is a place on Flock Rd. Have yet to ask the rent ... TIA Larry Levinson Talking up to the vocal ... LLevinson*Bloomberg.net (remove the star etc ....)

[Brian in Vancouver, BC]

Larry;

You should have the furnace in its own room, separate from the workshop. It should have a return air duct collecting air from the living spaces and it should get some outside air from a relatively small duct (about 6" dia. typically). You should not return air from the workshop, or that air will be circulated to the other living spaces, and spread the dust around (your wife will NOT like your hobby). Don't circulate heat to the workshop from the furnace or collect return air from that area.

(I work in a garage with only a 1500 W radiant heater and when its 50 deg F in there, its "warm". Some days its between 34 and 44 deg F. If you need some heat, use an electric radiant unit or baseboard.

Brian

[Larry Levinson]

we haven't noticed a problem with the dust going from the workshop, through the furnace, to the rest of the house. apparently, it just goes from the workshop, to the furnace, AND STAYS THERE. sigh. but thanks. May be a 6" duct for outside air isn't such a bad idea .. though, punching that hole in the wall doesn't sound like fun ...

"Brian >Larry;

Larry Levinson Talking up to the vocal ... LLevinson*Bloomberg.net (remove the star etc ....)

[Bob S.]

Larry,

I know this may sound costly, but it may turn out to be about a draw compared with some other options you listed.

You didn't say what kind of furnace you have but sounds like it depends on inside air to be drawn in for combustion. Look at direct vent furnaces. Mine is a Carrier that uses 2" PVC pipes to draw in outside air and vents the exhaust via another 2" PVC pipe. I also have a Central air unit.

Don't know how old the unit is but check with your local utility and see about any upgrades they may be co-sponsoring with local furnace suppliers to encourage installing energy efficient appliances. We were pleasantly surprised when we switched from electric to natural gas and got a $100 rebate from the utility as well as $200 from Carrier.

Bob S.

[Bob S.]

etc., etc.

Bob S.

[Jay Windley]

Nor have I, with my forced-air natural gas heater, which shares a space with the shop. Keep in mind that the air supply in the room where the furnace is generally does *not* mix with the air that's being heated, nor should it ideally. The air in the furnace room provides the oxygen for combustion of whatever you're burning in order to generate heat. The air to be heated is drawn in from the returns in the house and is kept separate from the air in the shop (and the combustion gases) by a heat exchanger. The only shop air that mixes with the heated air is what leaks around the edges of the filter on the return plenum.

If you're going to work in the same room as your heater, you need ventilation. I always keep a window open, even when I'm not doing anything woodworkingly that would require it.

I shut off the heater and vacuum it out every week or so. You don't want sawdust or anything caking up in there and being ignited. Generally I don't let sawdust aerosolize enough to warrant the danger of explosion. You really want to think about dust collection for the tools.

I avoid using oil-based products in that room at all, but if I have to I do it at the opposite end of the room, under a window that has forced ventilation outward.

--Jay

[Toller]

Don't forget that all the combustion air you bring in means that heated air has to be forced out somewhere else.

[Bob Summers]

Do you mean the chimney?

Bob S

[Larry Levinson]

many thanks. ...

If I had a really good sig file, this is where it would go ....

[keith nuttle]

[bob]

My shop shares space with a gas forced air furnace and two gas water heaters. There is no wall separating the shop and I've never had a problem. I change the furnace filter a couple times a year - and it doesn't look that bad when I do. All of this is in an unfinished basement with a double garage door and a Delta 1100 cfm collector. All return air comes in from upstairs. The table saw (the worst offender with dust) is about 25 feet away by the garage door, which I open even with the DC connected. I never paint or use solvents by the water heaters - I get far away, by the garage door or go outside whenever possible.

Bob

[Tim Carver]

You really need to do this, because you don't want to be drawing your combustion air from heated space. Ideally, the furnace would be in a little room by itself, with a direct opening through an exterior wall to the outside air. Alternatively, you could have a duct to the outside air, and a separated combustion furnace, with no need to have the furnace in a room by itself.

I do know that there are limits to what you're allowed to do to get outside air into a furnace. The general idea is that if a long duct for outside air is required, you're really supposed to be using a separated combustion furnace. You can't just run a long air duct right up to an ordinary furnace - that's what separated combustion furnaces are supposed to be for.

Why would you have lint in your laundry room? Are you running an unvented dryer in there or something? Anyway, if the laundry room is unheated and has an opening to the outside air, you're in business. If the laundry room is heated, you're going to be sending heated air out of the room and up the vent, while causing cold air to have to come into the room from somewhere else in the house - not good, it's just like when you have to open a door to have a decent fire in a fireplace that was built with no proper combustion air intake.

Is this different form (b).?

Furnace is in a room by itself with an opening right by the furnace for outside air - this is fairly typical in daylight basements.

Tim Carver [e-mail]

[Clarke Echols]

Your problem is your dust collector system. If you have fine dust in the air while the furnace is running, it will draw the dust in with the combustion air from your shop. The dust goes in with the air into the burner tubes where it mixes with the gas. The gas/air mixture then goes up through the burner plate or orifices, but the dust will be left behind as it settles out of the air stream, eventually plugging the burners. If the fires are off (shut the furnace down), there is no air flow and no dust gets transported in and deposited.

HOWEVER, the dust-laden air that plugs your furnace also plugs your lungs and you are setting yourself up for serious health problems in the future if you don't eliminate the flour-like dust from the air. It will get into your lungs as you breathe in and stay there, causing polyps, cancer, asthma or any number of other respiratory ailments (anyone for emphysema?).

A well-designed cyclone dust collection system with proper 0.3 micron filtration after the blower will eliminate the dust problem. If you have a 10" table saw, you need a cyclone dust collector that provides a "real-world" 900-1000 CFM, at least, and don't use the cloth filter bags. You need pleated, high-efficiency filters.

Bill Pentz nearly died from the effects of wood dust aggravating a pre-existing condition. He has done extensive research on the subject and has designed a cyclone dust collector. I produce a kit based on his research and design work by his invitation. I also produce a matching welded steel blower housing to match. Add a motor, impeller, filters, and ductwork and you have a first-class cyclone dust collection system for less than the price of a new Kirby, Rainbow, or Interstate Engineering household vacuum cleaner. Not only will you get rid of the furnace problem, but you'll be protecting your health at the same time.

For more info, see Bill's site at:

the kit and blower-housing information at:

me privately if you have further questions.

Clarke

Larry Lev>

[Lawrence Wasserman]

Actually, I believe he CAN forget that...