# Any ideas on why this happened?



## plumberkc (Jun 23, 2011)

I installed this heater two days ago. I solder my adapters before connecting to the water heater. 

The plastic hot and cold rings have melted and It must be from the flue heating up. In pretty sure none of my other heaters have done this. I just happened to be back to do some other jobs.


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## SchmitzPlumbing (May 5, 2014)

i am guessing that your flue is blocked up. i have seen bird nests in them or bricks and mortar fall down and block it up. look down the chimney from the roof . if those are melting, carbon monoxide is also coming out.


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## Hoosier Plumber (Nov 28, 2013)

Lack of draft. 

Strike a match or burn a piece of paper and put it near the draft hood, if it doesn't draw smoke you have a problem.


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## plumbdrum (Nov 30, 2013)

So you Bio says you do water heaters and you don't know why the plastic pieces are melting. WOW!!!!! Your a dangerous man for not even checking draft before you left.

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## plumbdrum (Nov 30, 2013)

And to boot not enough rise off your connector, 3" may not be large enough . I won't mention vacuum relief valve. Also is that cortisol I see on the seem ?

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## plumbdrum (Nov 30, 2013)

Corrosion

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## Va. Plumber (Dec 8, 2008)

I had that happen at my house. It was caused from negative pressure in the house. I have an attic fan on my roof and the screens that let air into the attic were clogged so the fan had to get air from somewhere and that flue was the perfect place to pull it from. I cleaned the screens and all is fine after that. The flue would draft fine with the attic fan off.


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## Associated Plum (Nov 4, 2008)

Are the nipples cocked towards the outside of the heater instead of straight?

I don't see any burn marks on the plastic.

From what I can tell it looks like expansion from overheating.


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## Plumbworker (Oct 23, 2008)

Obvious lack of draft..


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## Master Mark (Aug 14, 2009)

I just melted one on tuesday the same way on top
of a Rheem heater... I got up on the roof and the 
draft hood had somehow totally crammed itself down
onto the chimmney and had sealed it off ... something must have happenned this winter to it,,, 

I took off the draft hood on the chimmney and you could feel a blast of hot air escape out the chimmney..

I was probably lucky that it did not blow the oil vial in the Rheem heater.....


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## mrjasontgreek (May 21, 2014)

To basically repeat what everyone has already said, looks like blocked vent or negative pressure in the house. check the flue, check any ventilation intake screens on the house, you may need make-up air...


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## plumberkc (Jun 23, 2011)

I should have mentioned that there was no downdraft when I checked after first lighting the heater. Thanks for your comment though, plumdrum. There was not a strong draft but definitely some draw. The house is 14 years old, located in a nice area.

We did have some rain the other day, I'm wondering if the vent cap is damaged and the rain may have impacted things. 

There has already been a roofer and HVAC contractor out. For the last few months water has been coming from either the flue or ductwork. Each said the problem was with the other trade.


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## Cal (Jun 17, 2008)

plumberkc said:


> I should have mentioned that there was no downdraft when I checked after first lighting the heater. Thanks for your comment though, plumdrum. There was not a strong draft but definitely some draw. The house is 14 years old, located in a nice area. We did have some rain the other day, I'm wondering if the vent cap is damaged and the rain may have impacted things. There has already been a roofer and HVAC contractor out. For the last few months water has been coming from either the flue or ductwork. Each said the problem was with the other trade.


In all honesty ,,, sounds silly but , try turning the draft hood to where the straight sides are lined up with the nipples. Right now you are drafting onto the nipples. 
I know sounds simple but try it .


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## PoodleHeadMikey (Jun 21, 2014)

*Intermittent backdraft? Or constant backdraft?*

If flue gas is coming out of the bottom of the draft hood only when the WH burner is firing - the chimney is likely blocked.

If the backdraft is constant (firing or not) then there is a negative pressure problem in the building. Does the mechanical room containing this WH have the proper fresh air inlet? Are there mechanically vented appliances also in the space? 

And a negative pressure backdraft can also be intermittent due to cycling of exhaust fans and venting of the space (doors open or not, etc.)

You will want to check all those things. Was this job code inspected?

PHM
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plumberkc said:


> I installed this heater two days ago. I solder my adapters before connecting to the water heater.
> 
> The plastic hot and cold rings have melted and It must be from the flue heating up. In pretty sure none of my other heaters have done this. I just happened to be back to do some other jobs.


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## mrjasontgreek (May 21, 2014)

Also negative pressure can be influenced by opening or closing of windows and doors, if the problem is intermittent check draft with all windows and doors shut and hvac equipment in its highest speed setting


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## saysflushable (Jun 15, 2009)

I bet he needs to turn the vent hood a .25 turn. I would check for draft and negative pressure also. Cal said it 1st but as soon as I saw the pic that's what I thought


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## plumbdrum (Nov 30, 2013)

saysflushable said:


> I bet he needs to turn the vent hood a .25 turn. I would check for draft and negative pressure also. Cal said it 1st but as soon as I saw the pic that's what I thought


You guys are cracking me up with the turning of the draft hood solution. There is clearly a drafting issue, what good is turning the draft hood going to do? So if it's got poor draft the 1/4" wide post on the hood is going to prevent it from melting? WOW, just when I thought I've heard it all.

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## Coolcanuck (Jan 30, 2012)

One I installed the other day was back drafting when the furnace blower started up. I knew there was going to be an issue before hand due to the condition of the existing venting. Damn WWII time housing.


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## wyrickmech (Mar 16, 2013)

Coolcanuck said:


> One I installed the other day was back drafting when the furnace blower started up. I knew there was going to be an issue before hand due to the condition of the existing venting. Damn WWII time housing.


 you may be on to something here what else is hooked to the vent. Why is it back drafting? There is a issue with the vent that is not in question but is there something else cycling on and off that is causing the issue. Check the furnace vent and type of furnace venting I think you may find the answer there.


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## Redwood (Sep 8, 2008)

That turning the draft hood is about as funny as the toilet emptying itself being a vent problem.... :blink:

Only with possible deadly consequences this time.... 

*Yea I get it that there is a flat side of the hood and having the flat side there could possibly... maybe... prevent the spillover from melting the plastic collars...*

*But it is unlikely and it certainly would not stop the spillover from happening....*:yes:

It is time to get a real troubleshooter in there to diagnose the problem with the drafting and yes that would entail looking at all the parts of the existing vent and chimney, other uses of the chimney, and possible negative pressures in the building....

So Plumber KC, When are you going to spill the beans on what you found or, are you going to let these guys flounder a little while longer? :laughing:


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## SchmitzPlumbing (May 5, 2014)

you might as well turn your aav 1/4 turn to make that work better as well:laughing:


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## plumbdrum (Nov 30, 2013)

SchmitzPlumbing said:


> you might as well turn your aav 1/4 turn to make that work better as well:laughing:


Now that's funny

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## plumbdrum (Nov 30, 2013)

The first time I looked at the picture, I swear I see some corrosion on a seam. That must be from all the humidity they have in KC, oh that's right it's a dry heat out there right?

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## Cal (Jun 17, 2008)

Ok fellas ,, we'll wait and see what the problem & solution are . Laugh it up ,,,


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## plumbdrum (Nov 30, 2013)

Can't be as bad as the one I saw yesterday . 50 gal gas atmospheric draft, single walled out the side of the house. Wish I had taken pictures, called Gas Co. To shut her down, it's funny I don't think I saw plastic rings on water pipes, maybe the plumber took them off cause he didn't want to melt them when he soldered. Laughing😆😆

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## MNplumb1 (Feb 17, 2014)

Had a brand new 30 gallon atmospheric that would trip high limit on bottom of heater. Replaced gas valve, no help , venting was clear but 3" changed venting to 4" no help. Once salesmen warranted heater noticed that flue baffle was compressed and was only partially drafting. Was an ao smith. New water heater now works beautiful


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## saysflushable (Jun 15, 2009)

You guys are probebly right and putting the vent hood on the way the factory ment for it to be installed won,t make a bit of difference but I would still do it. Oh heck it might take 3 minutes for me and I,m slow. Are your fresh air vents plugged . I think he did say it was drafting when he checked it. so I;ll take him at his word. Is it drafting properly all the time? That is the question


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## Coolcanuck (Jan 30, 2012)

wyrickmech said:


> you may be on to something here what else is hooked to the vent. Why is it back drafting? There is a issue with the vent that is not in question but is there something else cycling on and off that is causing the issue. Check the furnace vent and type of furnace venting I think you may find the answer there.


It was only back drafting when the blower started on the furnace. There was an open vent at the ceiling of the mechanical room, air pot was above the draft hood. There was also a crawl space under the building and I'm not sure if that space was being heated by the furnace. I think the open vent in the ceiling was meant for fresh air into the return of the furnace. I did my job, sealed up what I could on the existing ducting, with no change, and let the office know we should be doing further work on this hazardous condition. Haven't heard anything back yet.


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## plumbdrum (Nov 30, 2013)

Coolcanuck said:


> It was only back drafting when the blower started on the furnace. There was an open vent at the ceiling of the mechanical room, air pot was above the draft hood. There was also a crawl space under the building and I'm not sure if that space was being heated by the furnace. I think the open vent in the ceiling was meant for fresh air into the return of the furnace. I did my job, sealed up what I could on the existing ducting, with no change, and let the office know we should be doing further work on this hazardous condition. Haven't heard anything back yet.


Cracked heat exchange ?

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## Coolcanuck (Jan 30, 2012)

plumbdrum said:


> Cracked heat exchange ?
> 
> Sent from my iPhone using PlumbingZone


Nah, it was was firing fine. Can't proceed with any work without the clients ok, the problem of quoted work. IMHO the furnace is the issue and should be shut off until resolved, but that's my journeyman's decision to make.


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## wyrickmech (Mar 16, 2013)

Coolcanuck said:


> It was only back drafting when the blower started on the furnace. There was an open vent at the ceiling of the mechanical room, air pot was above the draft hood. There was also a crawl space under the building and I'm not sure if that space was being heated by the furnace. I think the open vent in the ceiling was meant for fresh air into the return of the furnace. I did my job, sealed up what I could on the existing ducting, with no change, and let the office know we should be doing further work on this hazardous condition. Haven't heard anything back yet.


 you have two types of venting systems. They must be separated to keep the problem from continuing. Positive pressure from the furnace will push flue gasses where ever it can and will stop drafting.


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## plumbdrum (Nov 30, 2013)

If it's a fan assisted it can vent with atmospheric appliances. That's if it's is a type 1 appliance, if not then he is correct, i the flue needs to be separated , furnace vents to the outside on its own, it would be a type 3 appliance

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## plumbdrum (Nov 30, 2013)

Coolcanuck said:


> It was only back drafting when the blower started on the furnace. There was an open vent at the ceiling of the mechanical room, air pot was above the draft hood. There was also a crawl space under the building and I'm not sure if that space was being heated by the furnace. I think the open vent in the ceiling was meant for fresh air into the return of the furnace. I did my job, sealed up what I could on the existing ducting, with no change, and let the office know we should be doing further work on this hazardous condition. Haven't heard anything back yet.


Now that I've read this again, the return not connected to the furnace is definitely your problem, have someone hook it up and that should solve your problem

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