Expert: James Ball - 11/27/2011

Question
I have recently installed a gas heater into an existing chimney that has a gas heater hot water tank to it as well. The gas heater is a 4" vent and the hot water tank is a 3" vent. I have used B vent for the stove. The existing chimney is an old metal furnace chimney that measures 4" x 12". Everything works OK until I turn on the blower for the gas heater, then I get a strong odor from the gas heater. I am wondering if the old chimney is the wrong size for the combination of the hot water heater and the gas stove. If that is my problem, is there a liner that I can place into the 4" X 12" chimney that will correct the problem?

Answer
Hello Frank, some thing is very strange about this set up from what you explain, you say "gas heater" is this like a stove (like a wood burning stove but gas?) or boiler for heat of the home? I am not sure what you have there, can you send me a picture? I have never heard of a 4" x 12" metal chimney or flue (or is that a 4" by 12' tall?)?
That "strong odor" tells me you could have a deadly set up there and do not use it.
But either way I would have a local Certified Chimney Sweep www.csia.org, (there you can look up by zip code to find one near you) take a first hand look at what you have, they should be able to help.
Hope this helps
James