Newbie seeks advice...

[John Clapp]

Hello everyone... brand new here. Been looking around the site for a few weeks and learning a lot of good stuff. Hoping to pick a few brains with my question.

My shop is an attached 2-car garage with a water heater in one corner. Would have preferred the WH being somewhere else - but it's what I'm stuck with. I'm using DC and will be adding a ceiling unit soon... but in the meantime I'm worried about the dust getting to the pilot light on the WH. Not to mention being scared to death to try using finish out there with the garage closed up.

Question is - should I enclose the WH? If so, how much space should I allow around it? Would I need to include some sort of vent to allow air to circulate to the WH, or would that defeat the purpose of enclosing it?

Any and all suggestions are welcome!

[Leland Berry]

John, I'm new also but I'll try to help. I think you're on the right track already because "scared" is good in your situation, because you may have a ticking bomb-not just from ignited sawdust but ignition of the fumes. The WH needs a vent for supply air AND vent for combustion. To enclose it may shut off the former. A vent to the outside might help-"might" being
the operative word here because you won't know if it works, only if it does NOT. A safer alternative and cheaper in the long run would be switch to an electric WH, then vent fumes and dust separately as planned. Peace of mind and restfull sleep is worth something. Good luck -LB Benton AR

[Eric Gustafson]

I have a gas water heater and furnace in my garage. It is in a separate closest and gets its combustion air from a 6" x24" duct that vents outside.

[Gary Whitt]

A vent to the outside might help-"might" being the operative word here because you won't know if it works, only if it does NOT. A safer alternative and cheaper in the long run would be switch to an electric WH, then vent fumes and dust separately as planned.

Or...... add a small electric fan that blows air across the pilot light area. No dust can settle as it is being constantly moved by the fan.

[Brandon Shew]

Eric and Gary both have good points. Eric's may be better in the long run and a vent for combustion air is easy to install if you seal off the unit.

[John Clapp]

Thanks for the ideas! My problem (or concern) is that the exterior of the house is brick. How difficult would it be to put in a vent as described above... or would that be something better left to the pros? I'm quite certain I can enclose the WH... just not sure about the vent thru the wood and bricks part.

[Mike Kenney]

why dont you just put a air intake vent and filter on the door your gonna use to seal up the WH?

[Don Hein]

I assume that the WH exhaust is vented up, through the ceiling and eventually the roof? If you enclose the WH in its own room, and the exterior walls are brick, seems like vertical fresh air intake piping on the model of the exhaust piping would do the trick.

[John Clapp]

I assume that the WH exhaust is vented up, through the ceiling and eventually the roof? If you enclose the WH in its own room, and the exterior walls are brick, seems like vertical fresh air intake piping on the model of the exhaust piping would do the trick.

Don, you hit it on the head - the piping goes up thru the garage ceiling, thru the attic and out the roof.

Thanks everyone for the pointers... seems I had a bad case of "not seeing the forest for the trees". Been thinking on this one for several weeks and overlooking all the obvious answers.

[harry strasil]

why not just cut a vent in the ceiling above the water heater and let it get its air from the attic space, no need to go thru the roof.

[Al Willits]

Remember that gas burning devices that suffer from a lack of air can easily start making CO, next step is death to those in the house, it happens.
So, whatever you do, make sure not only the exhaust vent stays clear, but any intake you have does too, people tend to forget about intakes a lot.

Key here is keeping the LEL (lower explosive limit) from happening, whether its paint flumes, wood dust or any flammable vapor.

I have a furnace in my garage and have done everything from painting cars/motorcycles to woodworking now and never have thought of enclosing the furnace, BUT I do run a pretty good sized ventilation blower that pulls vapors/etc away from the furnace.
Unless your running close to a OSHA approved exhaust system, any of this is chancy, but if your going to do it you should try and make it a safe as you can.
Exhaust ventilation I think is what you should strive for imho, but remember you can pull a negative draft on the water heater if your garage is tight enough, that's not good either, so I probably should say intake AND exhaust is what you should work on.
Al

[Don Hein]

I have no special expertise in ventilation, but it occurs to me that a fresh air intake pipe to the WH should terminate down low, fairly close to where the flame occurs. If were to terminate near the top of the WH, the fresh air could make a quick turn into the exhaust vent at the top of the WH instead of going where it's wanted. This is purely speculation on my part; someone expert can speak to this.

[Al Willits]

Having learned to never say never in cases like this, try this...
Only reason exhaust goes up the vent in a normally aspirated water heater is, hot air rises.
At the draft hood of the water heater you will normally find a slight negative draft, but I'd think its not enough suck all the incoming air in, some dilution will happen but only enough to equalize the draft at the draft hood, the rest will/should go into the room which is in a slight negative pressure due to the air the water heater is using for combustion.

Famous last words....

Al...but yes lower would be better....I think

[Gary Whitt]

I have no special expertise in ventilation, but it occurs to me that a fresh air intake pipe to the WH should terminate down low, fairly close to where the flame occurs. If were to terminate near the top of the WH, the fresh air could make a quick turn into the exhaust vent at the top of the WH instead of going where it's wanted. This is purely speculation on my part; someone expert can speak to this.

As I learned backpacking.....

Draw low, vent high.


It relates to drawing fresh air from low (door of a tent) and venting the warm exhaled air out the top of the tent.