Thread: squished flue liner?

This can't be right can it? Squishing the liner like this? It has a boiler with a 8 inch and a water heater with a 3 inch flue connector venting into it. I don't even know why I'm asking. Of course it isn't right.

Similar Threads:

• ABS Flue Pipe on LP Water Heater
• High Efficiency Flue Termination
• Condensation On Flue Pipe
• Flue pipe
• Trained Chimpanzees Install Flue Pipe

Oh man!

Did you check to see if the appliances were spilling John?

Originally Posted by DavidR

Oh man!

Did you check to see if the appliances were spilling John?

Funny you should mention that. The boiler pilot was off, so I'm waiting for that to be done before going back and running the boiler. This is about 3 minutes from my house. The water heater was spilling, but I think that was mainly due to the flue connector being almost entirely horizontal (with proper slope up to chimney) and very little vertical.

Originally Posted by John Arnold

Funny you should mention that. The boiler pilot was off, so I'm waiting for that to be done before going back and running the boiler. This is about 3 minutes from my house. The water heater was spilling, but I think that was mainly due to the flue connector being almost entirely horizontal (with proper slope up to chimney) and very little vertical.

You would think that I've run up on this before wouldn't you?

This appears to be an ovalized liner. The termination does not appear to be factory ovalized. In spite of the square 13x13 flue tile on top, this flue probably pinches off to a slit opening that allows only this profile to pass. Most liner suppliers offer sizing charts with the effective flue area of ovalized liners. What you do is size the liner as a round based upon the input BTU/hr rating and height. Then use that size as a reference. You also have to derate corrugated liners 20% plus another 20% if there are offsets other than the 90 swept ell at the base.

The charts in the code start with a min. vent rise of 12". When they cut down the ell to come off the draft hood with a long flat run, you know it will vent better into the home than up the chimney, not to mention being a code violation. For ex., a 3" vent connector with a 12" rise is good for about 22,000 BTUs even though 99% of all water heaters use 3" vent connectors because that's the size of the draft hood collar. There are ways to improve on this setup.

What kills me is all these old iron monsters with the 8" collars for a home that could be heated with a modern boiler using a 5" collar.

If this thing is bad enough, they may have to replace that iron monster with a Mod/con boiler power vented out the side of the home. In that case, you could d/c the WH and let the mod/con heat the potable water, too and just seal off the flue.
Bob