Back draft

[Jason stewart]

I have a 2 year old State water heater with an atmospheric vent that struggles to stay operating due to a back draft through the vent duct. When it is running and it's really cold I can hold my hand between the top of the water heater and the duct.

What's the best way to counteract the draft and keep air from blowing in from the top and extinguishing the piolet light?

 

[Jeff Handy]

It’s possible that air is not “blowing in”, but air is being “sucked in”.

Your furnace, boiler, whatever, might be pulling in combustion air, and the easiest source is the vent for the water heater.

You might also have too much return air ducting from the furnace, and near the water heater, so the furnace is pulling really hard on basement air, and also is pulling air back down the water heater vent.

 

[Jeff Handy]

You might need to create an outside combustion air intake vent for either the furnace, water heater, or both.

That could lead to right near the burner area.

With a 4 inch pvc pipe, or 4 inch insulated metal duct.

You can find how-to vids for this on Youtube.

If your furnace already has a pvc air intake for combustion air, it might be partially blocked, or maybe something else is creating negative pressure problems.