Need Help On Chimney Liners

[igorg]

I have old furnace and old water tank heater both 19 years old.
I need to replace WTH.
Do I need chimney liner?
Both furnace and WTH are using the same chimney and my furnace is not high efficient.

I understand if I change furnace to High efficient my WTH would need chimney liner.

[jwortham]

I wouldn't think you would need to line it if you are only replacing the water heater.

http://www.eere.energy.gov/consumer/.../mytopic=12530

This link should give you some good info about the pros-cons.

[David P. Valley]

If your chimney is not deteriorating, and you're only replacing the WH, then I wouldn't worry about installing a new liner.

[jrupert]

As long as the tile liner of the existing chimney is in good shape then the Nation fuel Gas Code does not call for a liner for the water heater replacement. It does however if you are changing out the furnace with an 80% AFUE rating

[Gary Reecher]

Just a thought.

If you anticipate replacing the furnace in the future and will be going with a high efficiency furnace, which would be vented via plastic pvc piping, why not replace the natural draft water heater with either a direct vent, power vent or even look at the on demand gas water heaters.

If and when you replace the furnace the next time the roof is reroofed the chimney can be removed and you eliminate one more roof penetration that has the potential for a roof leak.

[rwand1]

If only a water heater, I would think that the size of the flue would be a factor, whether the chimney is inside the house or outside, and the height of the chimney. In my personal opinion I would be inclined to line the chimney.

However I like Gary's suggestion to replace the hot water heater with induced draft, negating need for the chimney.

[jrupert]

If the furnace is removed from the chimney leaving only the hot water heater, under the correct conditions it can have drafting issues. Those conditions will be influenced by if it’s masonry, tile lined or unlined, how large is the interior of the chimney, if the chimney is out side or runs up in the warmer center of the home ,how long is the water heater off, btu size, and of course where in the USA you happen to be. These factors will contribute to the chimney not heating up enough to establish proper venting presenting a possible carbon monoxide issue


With flue liners going for around $400.00 to $600.00 installed up grading to a better water heater is always the best option. Most HVAC companies that I am aware of will never leave just the H20 on a brick chimney