Venting hot water heater

Gravyfries

Hello, I just had a replacement boiler installed last week. They took the original flue from the water heater and brought it down to join the new boiler flue. Now there isn't nearly as much rise.  I also need a new water heater and I told the installers to account for the flue rise when installing the new boiler. I'm picking up a water heater tomorrow and was going to get a standard height heater which is about a half inch taller than my current water heater. Now I'm thinking maybe I should get the short version to account for a better rise and draft. The short version is about 8 inches shorter. Attached is a picture of the current heater configuration. It definitely rises from the water heater but looks like the flue pipe actually dips down before it goes into the T. Will I be ok in getting the taller version? I ask because it has a better warranty and energy rating. Thanks!

icesailor

Venting Water Heaters:

I love to see water heaters vent into a boiler vent through the bull of a tee. Such good draft. Did they know that they make Wye's to do that? Of course, there's no possibility of the boiler flue gasses blocking the bull of the tee when the boiler is running. And their is no possibility of the water heater being replaced with something just a little higher like all the new heaters are. Of course, you could just leave off the draft hood.

You could hook it up that way with the new one and it would "mostly" work. Maybe the shorter one would be a better choice.

My old boss from 35 years ago would have ripped my head off for doing that.

Mark Eatherton

Chris....

I caught your ironic drift, but you need to remember who it is that comes by here and reads this stuff. Most are weekend warriors. "I saw that it was OK to eliminate the draft hood on the internet..."



Please be mindful of this when you post here. Some people will take what you said literally, and will do what you said to do.



To the O.P., theoretically, the manufacturer would like to see 1 foot of straight vertical rise before the pipe heads horizontally, but some times, you can't get what they want without significantly modifying the existing chimney, and sometimes that modification is limited by the location of the tap into the chimney.



If you can't get the heater to draft correctly, you can go to National COmfort Institute and have one of their CO tech's apply a barometric damper and a spill switch to make it work correctly.



Proceed with caution.



ME

Lance

OOPS! Did I hear a shortcut error?

Never ever remove a draft hood that the manufacturer provides.

1) To get the engineering ratings it has to be there. It is part of the heaters design.

2) It is also a safety control. In a downdraft situation it diverts the draft to keep from interfering with the burner or pilot. When operating normal, a burner makes carbon dioxide, vents up chimney, in a downdraft it makes CO and vents into the house. This is science and engineering and a highly technical business and requires the people that do the work be learned, trained and most of all experienced if we are going to keep our customers alive and their property safe. 

3) If your house burns down and the draft diverter is not there, the survivors will not be compensated for insurance loss and it will invalidate the manufactuers warranty.

Fix the problem do the right solution it's cost is cheaper than your life and home.

Your installer was wrong to alter the vent connector. Especially if it fails the NFPA 54 gas code.

Lance

AOSmith warrranty tech rep and Master Plumber, Gasfitter and HVAC contractor.

Lance

Opps again.

From the picture the vent looks fine. The key question is does the heater pass the vent test and meet the code for your area. If it does it is OK.

Drafting flue vents can go wrong even when piped in right. It must pass the test or be modified. The code is a minimum standard and must be exceeded when needed.

Lance

Gravyfries

Thanks

The city inspector will be out this morning to have a look since they have to inspect the boiler installation.  I did a draft test by lighting a piece of cardbord (putting it out) and then see if the smoke vents up the flue.  The smoke vented just fine.  I just feel that if I get the shorter heater, it will have a good vertical rise straight out of the heater and then we can put a slightly better angle going in to the T.

Gravyfries

Inspection

Well, the inspector came out and had a look at the boiler install.  I noticed a tiny puddle of water and showed it to him.  It appears that the bolt connecting the circulator wasn't tight enough (I think he said flange?  I can't remember).   He said that I should probably have a "wye" instead of the "tee" for the flue connection.  I just wish they would have left the old heater connection the way it was.   Thanks all.  So much to learn.......