[kryptic89]

Hello, the flue above the water heater appears to point downwards a little, maybe by two inches. How problematic is this? Should I get it fixed? And if yes, how would I given that the water heater is already sitting at the base of the floor.

Thank you!

 

[rundawg]

Yes it is going down hill slightly, but because the 4” pipe right off the top of the WH is going into the larger pipe very quickly, the down hill slope is probably more horizontal.

Now that is assuming the pipe/chimney goes vertical on the other side of that block wall.

I don’t see any rusting on the top of the water heater, which is a good indication the flue gases are not regularly back drafting.

With that said, the only way to verify the WH is venting properly is with a combustion analysis, which includes a draft test on that vent pipe.

I also would recommend you purchase a “Low Level” CO monitor for the home to alert you to early exposure to any Carbon Monoxide.

 

[kryptic89]

Yes, that's probably right. I will get some CO monitors and indeed make sure we're okay on that front. This is in a home we're buying which we close on in 2 weeks. We kind of overlooked this issue at the inspection and didn't ask the sellers for remediation. But we'll test for CO as soon as we occupy the home. Is the draft test something that can be DIYed? Pardon my ignorance! Would it just be getting a thin strip of paper and seeing which way it bends at various points around the flue entrance? Thanks!

 

[STEVEusaPA]

Also not enough rise in the flue pipe off of the top of the water heater.

 

[rundawg]

Is the draft test something that can be DIYed? Pardon my ignorance! Would it just be getting a thin strip of paper and seeing which way it bends at various points around the flue entrance? Thanks!

No it is not. People think that just because air is flowing up the "draft hood" (opening in the vent pipe on top the WH), you are venting properly.

This is far from the truth. Too much air flowing up the draft hood will block flue gases from venting out of the WH, and spill them into the space.

Only proper instrumentation will tell you if the draft is adequate or not.

Proper draft only tells you the flue (vent pipe) has the ability to vent the combustion products. Only a combustion test showing stable CO and O2 numbers ensures the WH is actually venting.

 

[rundawg]

I will get some CO monitors and indeed make sure we're okay on that front.

Please investigate "Low Level" CO monitors.

Box store purchased UL listed CO detectors will not alert you until dangerous levels of CO are in the home.

Low level CO monitors will alarm in time for you to turn off the gas, ventilate the space, and investigate the problem.

 

[dougfamous]

Obviously the flue pipe is not right. In addition to the downhill pitch that oversized pipe its attached to could cause condensation problems later.

The good news: There's two options for fixing it.

The bad news: Neither one is easy.

Option 1 is to replace the water heater with a shorter tank that will allow for better venting.

Option 2 is to bust open the hole in the chimney to allow more pitch to the pipe. That PVC pipe running in front of it might need to be moved.

Either way, all of that oversized pipe should be removed and 4" run all the way and the chimney cemented back up.

PS: If that chimney is on the outside wall of the house AND the water heater is the only appliance that vents into it then you may also need a chimney liner installed to prevent the exhaust from condensing.