top of page
Search
A gas water heater beside a painted brick chimney in a Braintree basement, with its vent piping rising from the top of the tank, beside a navy title panel reading A Braintree Water Heater Vents Into a Chimney With No Liner.

A Braintree Water Heater Vents Into a Chimney With No Liner

Writer: Stephen Gaspar
Stephen Gaspar
3 hours ago
2 min read

I was in the basement of an older Braintree single family, working through the plumbing. The gas water heater stands in the corner beside the masonry chimney, and a metal vent connector runs from the top of the tank a short distance into the brick.

The water heater is a 2019 forty gallon natural gas unit. The chimney it vents into is not lined, and the connector enters the masonry without a proper thimble or sealed transition. There are substantial openings around the penetration.

A forced air furnace and a gas water heater standing together in an older basement, with white PVC vent piping running up from the furnace.
The basement mechanical corner. The furnace in front vents out through the white PVC. The gas water heater stands behind it at the right.

Up at the roof the same chimney has no cap, and several of the upper bricks are loose enough to move by hand. The masonry up there appears to have been rebuilt or repaired fairly recently, though the work is amateurish in appearance. The 2016 furnace standing in the same corner vents out through the sidewall in PVC. The water heater is what is left on the chimney. I did not test draft or combustion and I could not see the length of the flue from either end, so what I have is what was visible.

A galvanized vent connector entering a painted brick chimney through an opening in the masonry, with no thimble around the pipe.
The vent connector where it enters the chimney. The brick is broken open around the pipe and there is no thimble closing the gap.

A storage gas water heater is not sealed to the outdoors the way that sidewall vented furnace is. It depends on the chimney to develop draft and carry the products of combustion up and out of the building, and the whole path counts, starting at the draft hood on top of the tank. The connector is meant to pass into the masonry through a thimble, which holds the pipe where it belongs and closes the opening around it. The liner gives the flue a continuous passage of the right size and material, so the exhaust travels inside the liner rather than against bare brick. The Chimney Safety Institute of America states it plainly: a masonry chimney with no liner needs one when a new appliance is connected to it, whatever the fuel.

What needs to happen here is two trades. A licensed plumber or gas fitter installs a proper thimble and corrects the vent connection at the appliance. A chimney professional evaluates the flue and lines it as appropriate. The CPSC's guidance is to have the whole assembly looked at once a year, "including furnaces, boilers, fireplaces, wood stoves, water heaters, chimneys, flues and vents." The appliance and the flue are one system.

Comments

bottom of page