Just installed new gas hot water heater- extremely hot flue

[MikeC1234]

Hello All.

Had to get a new hot water heater today as my old one started leaking after 9 years. I replaced it with the exact same model (40 gallon Rheem low boy, natural gas, normal venting) and finished installing it a couple of hours ago.

When I disconnected the vent from the old one, I noticed a lot of debris in the horizontal duct leading to my chimney. I do not have a chimney liner so it vents direct into the 1920's masonry chimney. I cleaned it out the best I could and will call a chimney guy tomorrow and most likely get a liner installed and finally change the configuration of the vent pipes (my natural gas boiler vent enters the chimney above the hot water heater vent and I was told that is a no-no as but never got around to getting it modified).

My question is that the vent pipe for the new hot water heater is extremely hot, like very hot...like it sizzles when I touch a wet rag to it. It read 280 degrees in one section on my infrared temperature gun. It is a single wall vent pipe, and I do not make a habit of touching them regularly to get a good comparison, but still seems way hotter than it should be.

My CO2 detector is about 6 feet away and has not gone off yet so that is good news. My question is should the vent pipe get that hot? Maybe because it is heating a full tank of cold water?

 

[GrumpyPlumber]

Installing a gas/combustion fixture DIY is ill advised, both fire and CO hazard - in this case, the riser off the heater is too short, not knowing that tank's height, you might have purchased a shorter heater to resolve it.

 

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[Fitter30]

280° is in range. If there's a drafting problem the first sign is melted plastic around the water piping next to the draft hood.

 

[Weekend Handyman]

Installing a gas/combustion fixture DIY is ill advised, both fire and CO hazard - in this case, the riser off the heater is too short, not knowing that tank's height, you might have purchased a shorter heater to resolve it.

It always amazes me when folks choose to do their own gas work. I will DIY most plumbing projects, limit myself to basic electrical work, but won’t touch gas or oil with a 10 ft pole. The consequences are just too high … a flood is one thing, an explosion is quite another.

 

[Weekend Handyman]

280° is in range. If there's a drafting problem the first sign is melted plastic around the water piping next to the draft hood.

Is that shark bite supply line close enough to the flue pipe to get fried? Looks like it is pretty much touching.

 

[Tuttles Revenge]

It always amazes me when folks choose to do their own gas work. I will DIY most plumbing projects, limit myself to basic electrical work, but won’t touch gas or oil with a 10 ft pole. The consequences are just too high … a flood is one thing, an explosion is quite another.

While I'm happy that people are afraid of gas.. I just don't understand why.

Is that shark bite supply line close enough to the flue pipe to get fried? Looks like it is pretty much touching.

Yeah.. that looks WAY too close.

 

[Weekend Handyman]

While I'm happy that people are afraid of gas.. I just don't understand why.

Yeah.. that looks WAY too close.

Fear of blowing one’s self ill mostly

I get your point tho. People have a hard time with objectively assessing risk. For example, what is the more dangerous job police officer or garbage collector?

 

[GrumpyPlumber]

While I'm happy that people are afraid of gas.. I just don't understand why.

Yeah.. that looks WAY too close.

Every winter here after heat kicks on, there's are news stories once/twice a month about CO poisonings, fire or explosions due to faulty installs.

The CO one's are particularly sad & scary, families die in their sleep.

 

[Oldspicesocal]

Every winter here after heat kicks on, there's are news stories once/twice a month about CO poisonings, fire or explosions due to faulty installs.

The CO one's are particularly sad & scary, families die in their sleep.

It looks fine don’t listen to this guy, as long as it slopes up and recommended 12” riser before an elbow

Installing a gas/combustion fixture DIY is ill advised, both fire and CO hazard - in this case, the riser off the heater is too short, not knowing that tank's height, you might have purchased a shorter heater to resolve it.

 

[Fitter30]

Top joint off water heater looks like the crimped end isn't shoved in far enough metal tape doesn't cut it each joint should have three screws per joint. Install manual probably wants 12" straight pipe off the top before a ell. Furnace and water flue wh should be on top of the furnace flue. Just because it's always been on the bottom most codes wh on top.

 

[Nebojsa]

I had a similar setup. Replaced it after having a chimney liner installed to prevent the bricks from deteriorating further from the condensation especially during winters. I have both flues join into one just before entering the wall.

 

[Jeff H Young]

Installation not greatest . Ive had many that couldnt have a straight shot for a foot off the draft hood, but thats only one of the issues . Its good you plan on improving things , Some are easily achieved some are not I too dont care for the water lines being too close to heat of vent easy to improove on that. glad to hear you have CO detectors good idea for us all to have!
As far as the dangers of working on a gas connection lighting a pilot or hooking up a union I think some of the comments are hysterical phobias. People die from stupid mistakes yes drunk driving , sober driving , hooking up water heaters is down there on the lower end of risks but the consequences can be high. crossing a street walking to school should be illegal for children right?

 

[GReynolds929]

It looks fine don’t listen to this guy, as long as it slopes up and recommended 12” riser before an elbow

I'd like to see a source for the 12" rise. The manuals for the water heaters we install don't have this requirement.

 

[Jeff H Young]

A O smith ultra low nox 50 gal gas water heaters recomend in the manual but dont require 12 inches verticle rise befor the first 90. It could be because these are ultra low nox and not just low nox ?