Thread: Soot above water heater TPR Valve

Has anyone ever seen this condition before?

If so, any idea what the cause may be?

Thank you

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Looks like backdrafting, blocked vent, or similar combustion issue.

Dom.

Jon,

Like Dom said and often due to poor combustion/draft air, flame roll out or absent/misaligned inner door, usually also evident at the drain valve escutcheon.

Cleaned up a bit.

Is there a picture of the entire heater on the burner door side?

Of the venting arrangement above?

Can't tell from this picture, but sometimes it is a simple as the plumbers torch from installation.

Yes, here is the whole thing... and then the vent area.

Jon,

The flue pipe does not look like it has have the correct 1/4 inch per foot rise.

I see this on most gas water heaters. Inadequate chimney/ venting causes some flue gas spillage within the jacket of the water heater. You will usually see some signs of spillage at the draft hood, condensation and corrosion on the venting and top of the unit with this. Just another piece of the puzzle.

There should not be a torch near that TPR. Sweat the drain tube onto the fitting first then screw it in as a unit.

Bob

"Can't tell from this picture, but sometimes it is a simple as the plumbers torch from installation."

Jim
I was also thinking the same thing, but then I thought, no you can't torch the TPR valve. So I checked 2 TPR valves I have on hand, both are threaded.

There should not be a torch near that TPR. Sweat the drain tube onto the fitting first then screw it in as a unit.

Agreed, but did Bubba know that?

I was also thinking the same thing, but then I thought, no you can't torch the TPR valve. So I checked 2 TPR valves I have on hand, both are threaded.

Yes, all the TPR valves of this sort are threaded, but the adapter is not. And we all know that bubba would have to wait for it to cool and have a straight joint if he sweated the pipe onto the adapter before installing it.

I think, after seeing the other photos, that it is even more likely that the torch may have had a hand in this. I don't see any other evidence around the door, etc. of flame roll out and the likes that have been mentioned. But then, I was not there.

My first thought was a torch, then (like the others) 'but what would the plumbers be doing with a torch there'?

Originally Posted by Bob Harper

I see this on most gas water heaters. Inadequate chimney/ venting causes some flue gas spillage within the jacket of the water heater.

The spillage "within" the jacket, escapes from the highest opening - the T&P.

Just another piece of the puzzle.

And what a puzzle they can be.

Jon,

From the amount of rust on the bottom of the other Fired appliance in the Picture where there any issues there?

I doubt it was the plumber's torch. I see no blistering of paint, no melting of the plastic escutcheon around the TPR and look at the solder on the cold water inlet-- this was soldered off the unit first, screwed in then soldered to the pipes as it should have been. The solder would not run uphill when he sweated the cold inlet to the adapter. That solder was wiped while hot. Also, he knows not to apply heat close to delicate fittings. The plumber also knows from experience it is much easier and faster to sweat the adapter onto the pipe, let it cool, then screw it into the TPR than to try and hold it up into the adapter without it falling out while he's soldering--takes 3-4 hands that way.

You always sweat adapters first then screw then in.

I would replace that old gas cock with a modern ball valve listed to ANSI Z21.15. Those old ones tend to leak or stick.

I stick with venting and CAZ pressure issues.
Bob

Jim
If the soot was caused by trying to sweat a fitting, I expect to see soot beside and below the TPR (near the sweated fitting), not centered and above the TPR.

I'm sure it was not from a torch, the soot wiped off with my finger.

As for the furnace, it is an old 30 + year GE unit that is in need of replacement. No signs of spillage there.

I personally have never seen spillage from within the jacket, but that sounds like a reasonable cause.

Thank you,
Jon