Does my chimney need a liner?
I had a home energy audit earlier this year, courtesy of my utility company. One of the findings was that my boiler wasn't venting properly. (It was venting out, but not strong enough to their recommendations) I had it looked at by a chimney service, who discovered that the vent stack from my gas water heater and boiler goes into the (brick) chimney, does a 90 degree turn, then ends, dumping out into the chimney. (the inside of the chimney is just the brick, there's no metal of clay liner going up) They said it should have pipe running all the way to the top of the chimney to draft/vent properly, and left a $1800 estimate.
Do Gas boiler/WH's need their vent pipes to run the full height up a chimney? The setup is ~20+ y/o and hasn't been a problem. Would there be a 'better' expert to consult?