Make up air for atmospheric water heater

[rogerg]

I have a gas licence but it's been a few years and different areas have different codes. Here are a few things from MY experience: How do you know there wasn't spillage problems before you got there? I would think a problem existed before you got there. How 'insulating and sealing' makes it your problem is beyond me.
The vent on top of the water heater looks like 3inch. Never seen it that small.
The furnace looks like what we used to call mid efficient where the exhaust is plastic and moved outside yet the intake is very close(on top of the furnace) to the hot water venting. Still,I believe, not your problem.
In a large open basement we would not have to supply extra intake air.
The venting is a bit wiggly but should work (though small size). We tried to go vertical as much as possible before using elbows.
Anyone check the rest of the venting:inside the wall, above the roof etc?
The dryer right beside it sucking in lots of air might cause issue.Which brings up; think of a gas range with all the top burners on impinging (very bad) on pots of cold water, all without venting to the outside. Makes you think doesn't it?
Anyways, that's my quick take.

roger

[ThingOfBeauty]

Looks like it will be very easy to pop the power-vent flue out the wall near the dryer duct.
That's by far the best solution, safest and most efficient.

[Ted S.]

I have a gas licence but it's been a few years and different areas have different codes. Here are a few things from MY experience: How do you know there wasn't spillage problems before you got there? I would think a problem existed before you got there. How 'insulating and sealing' makes it your problem is beyond me.

It was an energy retrofit through a program so there probably was a "test in" , the homeowner was probably made aware of the potential problem. I have been in the situation where it was my problem, but he doesn't seem to be in the same situation.

[justinae]

Thanks for all the replies.

Yes this is a BPI Certified test in. The heater failed worst case depressurization. In fact, for those that are interested, it was -9.5. There was a kitchen hood that was drawing almost 5Pa by itself. Anyway, we opened a 2 square foot window all the way and that still didn't bring us down enough.

So we're left with replacing the heater. The good news is that we discovered that the panel, though old and slightly underpowered, had a two pole 30amp breaker from a prior water heater that was not being used. With a 15' run of exterior conduit and a new Marathon water heater I think we'll be in business and at much less cost than the power vent. Still waiting for proposals though.

If anyone wants I can post our final conclusion.

Thanks!

[rogerg]

Thanks for all the replies.

Yes this is a BPI Certified test in. The heater failed worst case depressurization. In fact, for those that are interested, it was -9.5. There was a kitchen hood that was drawing almost 5Pa by itself. Anyway, we opened a 2 square foot window all the way and that still didn't bring us down enough.

So we're left with replacing the heater.

Sort of an unusual way to solve a venting problem but hey, it's your call.

roger

[justinae]

Sort of an unusual way to solve a venting problem but hey, it's your call.

roger

Nope. The current heater is back drafting under test scenario that I am bound by. You cannot just convert an atmospheric to direct vent and the amount of make up air needed far exceeds any reasonable "hole in the wall" we could install. As far as I see it this is the most cost effective and responsible way to solve a potentially dangerous venting problem.

[rogerg]

I'm not saying you are wrong. You as a contractor is looking it as a contractor. Me as a gas fitter for 4 decades has come across a multitude of back drafting for various reasons and never had to tell the customer to get a different type of appliance (gas to elec. etc etc).
An open basement has more than enough air because, hopefully the furnace guy wouldn't have put the furnace down there.
Opening a 2foot window didn't solve the problem so it would seem it is not a combustion air problem but a venting problem.
Hot air rises and it's either a vacuum (negative pressure) that's stopping it (the open window blows that theory) or the vent is the problem. Maybe where the 6inch pipe is jammed through the wall (seen that) or where the termination at roof level is causing a down draft (seen that many time). Pipe going up too small or collapsed (seen that).
I just view the problem from a different perspective and we all have to deal with problems that come up and as long as you and the customer are happy that is all you have to worry about,

roger

[justinae]

I wish we could just address the venting problem. Perhaps you're right that it's only that. Since the project is funded and regulated by the local program we don't even get to go that route. Once we fail the the depressurization it doesn't even matter what we do. We either have to fix the ZONE (i.e. make up air, confine the zone, etc.) or we have to change the appliances in the zone which put us in a different category. Unfortunately for the customer that is where we are at and thankfully we had the presence of mind to tip them off to the possibility ahead of time.

Either way, I appreciate the good discussion and wisdom in the "room".

[Ted S.]

I think a lot of it comes down to the BPI Standards.

The testing, analysis, and solution are all derivatives of the BPI Standards, I'd be surprised if one could follow this discussion without having gone through BPI training. Only because it is so based on the BPI's proprietary standard.

Having said that, roger is obviously far advanced from the BPI's level of training. All were talking about is a simply set of rules set by a state program. We're just following rules.

I find it interesting to get someones take on issues such as combustion safety who is in the business but not BPI, kind of eye opening.

I too am surprised that a 2' x 2' window didn't fix the problem, unfortunately we may never know what the issue was because according to the BPI the solution would be to change the equipment and move to a different category. I'd be interested in going deeper and understanding what caused the draft issue.

[rogerg]

Just an aside; the company I used to work for also did gas inspections and if there ever was a combustion air or venting problem ALL the gas appliances were Red Tagged(turned off) until the problem was solved. Whatever problem would/could affect all the appliances.
I guess you are lucky you didn't have to condemn the furnace. Power venting (the furnace) solved the venting problem but if there really is negative pressure then it would affect the 'atmospheric burner' in the furnace with combustion air.
Anyways, you asked for opinions and you got them:)

roger

[dgbldr]

Roger is absolutely correct. This thread amply illustrates how idiotic some of these "rules", "tests" and "standards" can be.

I don't know how to build a house that won't support combustion of an ordinary WH with a window open. But will support a furnace, gas dryer and kitchen hood! I need to go to BPI to learn how to build such a house. Ted, can you get me in?

You cannot just convert an atmospheric to direct vent

You can certainly replace it with a 2-pipe heater, which takes its combustion air from outside just like any high eff furnace.

[Hearthman]

A lot of things here. First of all, The furnace should have the second pipe for combustion air run. That open combustion air pipe is depressurizing the CAZ. Next, seal the return ducts. Then reinstall a supply grille discharging conditioned air into the CAZ.
The chimney should have a Level II inspection. I don't see a cleanout and can't tell if that's a liner or not. Regardless, the code calls for that vent connector to be upsized to 4" since there is less than 3ft of vent rise. Understand that passive makeup air does not work and was proven unreliable by and ASHRAE study. If it continues to spill replace the WH with a power vented one. That clothes dryer is adding to the depressurization. Lastly, fix the house. Seal the top of the thermal envelope and allow some passive infiltration below the Neutral Pressure Plane. HTH