NSR: Gas water heater combustions smell?

[char]

I recently installed a 40 gallon GE natural gas water heater in my basement.

I was planning on getting this inspected this week. I hooked it up and turned everything on after checking connections, etc. Everything was fine until today. It has been running for ~4 days.

Today I noticed a smell in the house that seems to be stronger near the basement. I have a CO monitor down there and it hasn't gone off and when tested it reports 0 ppm.

I've double checked the gas connections, and this definitely doesn't seem like a natural gas smell. I have it currently turned off at the valve on the gas line. I'm thinking this may be some sort of spill from the vent, but I can't figure it out.

The vent rises about 1/2 inch in 10 inches into a brick chimney. It rises slightly less than the original water heater because the new one is taller. Per the inspectors requirements I installed 2 100 sq inch vents in the wall to provide combustion air into the room.

My clothes dryer is in the same room. No issues with the older water heater.

This has me a little freaked out and I'm thinking of just switching over to an electric model for peace of mind. Higher costs though. I'm also considering renting the home in the future.

Any thoughts?

[Boddysurfer]

Make up a soapy water solution. Open the valve on the gas line. spray it on the joints/fittings on your gas line. If you get bubbling there's a leak. If not you have eliminated one potential problem.

[marmot mb]

flue gas rises and exists the venting system because of the heat in the flue gas itself.

New hot water heating applicances are more efficient, they are more efficeient because they strip more heat from the combustion process than older models, hence the flue gas has less heat left in it to take the remaining flue gas higher into your chimney.

Unless your furnace is running or you are having a fire, the air in the chimney is cold and not moving upward. when your hwt fires the flue gas goes up the pipe and into the chimney and then hits a "cold air plug" until such time as sufficient warm flue gas enters the chimney the cold air stops it from rising. In some extreme cases the newer applicances dont have enough heat left to actually be allowed to be vented into chimneys and need a dedicated vent.

I suspect that some flue gas is spilling, perhaps from draft hood on HWT IE spilling out, or perhaps from a clean out on the chimney or perhaps out some cracks on chimney.

cant say for sure but have seen this before, especially with new higher efficeincy applicances. read the owners manual carefully for you new HWT.

[char]

That was the first thing I did. No leaks from the heater to the valve and nothing from the valve back a few connections.

Smell goes away when I shut off the water heater.

[char]

I did the spillage test as outlined in the installation guide. Let it run 5-10 minutes and see if a match flame is pulled into the flue. It was. So I figured I was fine.

Maybe I'll have to look into running 3 inch venting up the flue...

[char]

flue gas rises and exists the venting system because of the heat in the flue gas itself.

New hot water heating applicances are more efficient, they are more efficeient because they strip more heat from the combustion process than older models, hence the flue gas has less heat left in it to take the remaining flue gas higher into your chimney.

Unless your furnace is running or you are having a fire, the air in the chimney is cold and not moving upward. when your hwt fires the flue gas goes up the pipe and into the chimney and then hits a "cold air plug" until such time as sufficient warm flue gas enters the chimney the cold air stops it from rising. In some extreme cases the newer applicances dont have enough heat left to actually be allowed to be vented into chimneys and need a dedicated vent.

I suspect that some flue gas is spilling, perhaps from draft hood on HWT IE spilling out, or perhaps from a clean out on the chimney or perhaps out some cracks on chimney.

cant say for sure but have seen this before, especially with new higher efficeincy applicances. read the owners manual carefully for you new HWT.

This makes alot of sense and while my manual doesn't require that I not vent into a chimney, it would seem I probably have a cold air plug and need to install a 3' flexible venting lining kit like this: http://www.northlineexpress.com/customkititems.asp?kc=5SP-2210-KIT

Edit- Interesting that my building inspector was so up in arm over some vents in the wall when the thing won't even vent right because it is going into a chimney that is too large for it.

I remember being told it needed to be lined when I bought the house, but I blew it off at the time. Now I know why, orphaned water heater.

[Alpinord]

That, or a power vent.

[marmot mb]

The chimney liner is a great idea but........ this means you cannot continue to use the chimney for wood burning (if it was before anyway). this product is intended to be run up inside the chimney space and terminate at the top with a proper termination cap and seal of the top of the chimney. In addition this product cannot take the heat produced and the byproducts of wood burning.

Flue gas condensation is a big problem that is not given enough consideration. when flue gas condeses it is HIGHLY corrosive (think ACID) it eats the mortor and the brick out very quickly. This is why using a chimney liner is such a good idea in addition to allowing the appliance to vent properly and maintain the highest efficiency.

A power vent can't really be added to a non Power vent appliance as it will simply strip the heat away from the appliance and the appliance will be far less efficient. This is not to say that there are not flue vent boosters available when properly sized to ensure it will not create too large a negative pressure on the flue system to the appliance and the manufacturers designed flue outlet pressure is maintained.

Ultimately my advice is get a professional Gas appliance technician involved, your family safety and your liability is not worth the risk and one can only do so much to trouble shoot things like this over the internet. Way too many variables that could be at play.

[char]

marmot- I will be getting my plumber involved in this on Monday.

This chimney is only used for the HWT, the wood stove has a separate pipe/chimney.

I'm thinking this is an orphaned water heater that needs it's own 3-4 inch flue to alleviate the situation you have described. I think one way or the other I will line the flue. None of this occurred to me as I was swapping a lower btu unit for a higher btu unit.

Will that liner work? It seems to be much cheaper than some other options out there.

Thanks for the help.

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