Water Heater Insufficient

[IFIXH20]

Yes I am sure about the tape

 

[stevemachine]

Yeah I would suggest either finding proper tape or not even worrying about it. With the flue being screwed in you should be fine. And ok well see what you can do. If you can even get 6" it's better than nothing. The more vertical the better.

 

[randmplumbing]

Drain your tank and try turning the temperature up a little bit.

 

[Renhoek]

And also not sure about your jurisdiction but in mine you aren't allowed to put a 90 right off the draft hood, should go up about a ft first. But that may depend on area

Hi,

I just posted a message asking for a video of a draft hood "smoke test". Then I saw that you suggested that some jurisdictions require a straight vent pipe right above the draft hood; is that to allow an unobstructed flow of hot exhaust to heat up the vent pipe properly?

The draft hood in the house I'm renting has two adjustable 3" vent joints attached before the first section of straight pipe. It looks like something from a Dr. Suess cartoon! I will post a photo to get your opinion.

I did the smoke test on my draft hood, and although the smoke from a stick of incense did get sucked in, it barely did. I was glad to see someone say that their smoke was sucked in from 2" away. My incense has to be right at the EDGE of the hood to get sucked in. I think this could be overheating the combustion chamber after a few minutes.

I have a problem with the pilot AND burner shutting down after 15 minutes and I want to know if it's venting well enough before I replace the HWH for nothing. Money is tight.

Thanks,

RH in CA
6/17/13

 

[Renhoek]

Here are three photos of the "Dr. Seuss" venting I mentioned just now.

The first is the draft hood -- no signs of back drafting, right?

The second show the two adjustable couplings that lead to the first section of straight vent pipe (which is about 4 feet long).

The last shows the 3" vent joining the larger natural gas furnace vent.

Any opinions about why the "smoke test" I did seems like it's not drafting fast enough to keep the combustion chamber from overheating and shutting off the pilot AND the burner every 15 minutes.

RH in CA

 

[lemmon]

Not sure the cause but it sounds like some type of safety feature is shutting it down on you. At that point I'd get a pro to take a look.

 

[ricvan]

Is the venting single or double walled ..... any code I look at when joining 2 appliances together with metal venting the whole system or at least where they join together(common venting) should be double walled(B-Vent)...unless venting into a masonry chimney at 2 separate locations of the chimney... there are a lot of bends in your exhaust that would also make your draw a lot lower in pressure than a straight run up would do

 

[stevemachine]

Yeah definitely doesn't look like it's up to code. Too many bends will create more restriction of flow for the flue gases. The more vertical the better negative draft you will have which is what you want. They kinda seem to go up at an angle instead of straight up then over to your common vent.

 

[stevemachine]

And it sounds like a TCO switch might be shot on your HWT. If it has one then that could be the problem. That's usually due to 3" venting on a hot water heater instead of 4". Plus those extra bends can't be helping

 

[Renhoek]

And it sounds like a TCO switch might be shot on your HWT. If it has one then that could be the problem. That's usually due to 3" venting on a hot water heater instead of 4". Plus those extra bends can't be helping

Thanks for all the feedback.

So far, I:

> replaced the original 200*C TCO/thermocouple assembly with the one that AO Smith said it listed. That is a 180*C "High Altitude" version. They swore it was the right part, so I installed it, even though I was never told what "High Altitude" referred to. Does anyone know?

> I inspected the flue baffle: looked OK.

> I vacuumed the top and bottom of the Cordite fire arrestor. I even pushed a thin guitar string through most of the holes to make sure they were clear.

> I swept a little rust off the top of the burner and vacuumed it all around.
(I had trouble getting the burner to sit on its support bracket, but AOS said it being off-center was NOT a safety problem. Should I believe them?).

> I vacuumed the inside of the combustion chamber. I replaced the fiberglass-looking gasket with a new one. The viewing window is fine.

> I drained about half the water from the tank: no sign of sediments.

> I have NOT done a "drop out test" -- what is that?

So far, the only thing that appears unusual is the draft hood test. If anyone can post one, or post a link to one, that would be great.

I will also post a photo of a 4-foot length of single-wall 3" pipe that I found near the boiler (AOS said that my 50-gallon boiler uses 3", not 4"). I think it was the original vent and a previous tenant changed it for some unknown reason. Maybe the boiler had a separate exit through the roof before someone joined it into the furnace vent...

I haven't vacuumed out the 3", single-walled exhaust vent because I figured that if a bird built a nest in it, I would smell roasted chicken. Or roasted squirrel.


Thanks again,

RH

 

[Renhoek]

Yeah definitely doesn't look like it's up to code. Too many bends will create more restriction of flow for the flue gases. The more vertical the better negative draft you will have which is what you want. They kinda seem to go up at an angle instead of straight up then over to your common vent.

Hi,

I think you are right. As I said, the smoke test I performed didn't seem to draw smoke very quickly into the exhaust/flue pipe.

And I found this 4' single-wall 3" pipe next to the boiler when I moved in last fall. If it were connected to the top of the HWT, it might have been too close to a rafter, and it seems to have exited the garage in a different spot (or out through the fireplace, which it's right next to).

The tarnished gray color of this pipe also matches the 4" furnace pipe, so I think it was in the house many years ago.

Not sure who might have changed it out, or why (a fire risk?), but I think the Stooge that replaced it did a crummy job. It might not even be up to code.

Any opinions are welcome.


RH

 

[stevemachine]

For the burner I wouldn't worry about it sitting on the bracket, that's just so it sits in the Centre of the tank. Drop out test is where you light the burner, let heat up the thermocouple for a few minutes then blow the flame out. The pilot gas will continue to come. Then the power unit should click. From the time you blow out the pilot till that click is your drop out test. 180 seconds is the maximum time allowed. With youLrs being a closed combustion chamber I wouldn't worry, this test doesn't apply to your situation really. In my code book 3" venting is only good for around 35000 btus (I won't get in depth, there's variables and charts) so 3" is rarely even used now a days. Charts have changed over the years which is why you still see it in service. 50 gallon never ever uses 3", not in my experience. Ultimately the venting needs to be changed. That's the root cause.

 

[stevemachine]

And let's post on your created one instead of hijacking this one

 

[LiQuId]

It is against code to use ANY tape on the Vent piping, you need to use 3 screws and NO tape. Also the acidity from the boiler discharge will destroy the mortar in the joints holding the chimny together in no time. to do this Correctlly you need to have a liner pulled in the chimney but you STILL wouldnt be able to have those 2 appliances vented that close to each other and in that mannor.

also you cant Toss a 90' bend right off of the top of the flue collar.

AND I can see that you love sharkbite ( those shark flex connectors arnt cheap either ) but you are asking for many problems looking at the pics in general. At least Dont have the flex connector touching the vent ( 6" minimum distance between single wall and objects.

Not trying to be a dick, but YOU need a professional.

 

[Renhoek]

It is against code to use ANY tape on the Vent piping, you need to use 3 screws and NO tape. Also the acidity from the boiler discharge will destroy the mortar in the joints holding the chimny together in no time. to do this Correctlly you need to have a liner pulled in the chimney but you STILL wouldnt be able to have those 2 appliances vented that close to each other and in that mannor.

also you cant Toss a 90' bend right off of the top of the flue collar.

AND I can see that you love sharkbite ( those shark flex connectors arnt cheap either ) but you are asking for many problems looking at the pics in general. At least Dont have the flex connector touching the vent ( 6" minimum distance between single wall and objects.

Not trying to be a dick, but YOU need a professional.

> The tape is not holding the vent pipes together: they are screwed together, the tape is just preventing gas from leaking into the garage. But it's A/C duct tape and I think I should replace it with the correct tape, if at all.

> I agree that, since this failed the "smoke test", the venting IS my problem.

> I appreciate ALL opinions, and yes, I wish I could call in another (it would be the fourth) pro.




RH

 

[lemmon]

Quick Question concerning tcouplers and pilot lights
i read somewhere that if your pilot light is too high it will burn out tcouplers very quickly
My original one lasted 5 years now I've been replacing them every 6 months or so
any insight