Omg Now What Am I Going to Do?

GaryFerg · Post by **GaryFerg** » Thu. Jan. 30, 2014 7:22 pm

Today when I got home I walked into my shed to check my boiler to find a steam filled room. The pex pipe leaving my boiler to my basement about 30 feet had broken and collapsed. The stove must have gotten so hot that it melted the pipe. Not sure what happened yet maybe the circulator failed? any way I am at a lost on how I am going to fix it. There isn't enough good pipe to grab onto to patch. I want to try and see if I can use a come along and pull some more through but this is doubtful. I am thinking for a temp fix I will lay black steal pipe along the ground and patch it in that way or maybe I can dig up enough pipe to patch in somewhere. I am thinking for the big fix, to use the black pipe and insulate it underground any suggestions?

grumpy · Post by **grumpy** » Thu. Jan. 30, 2014 7:28 pm

Black pipe sounds expensive, why not dig up the PEX and add a new section, a joint underground kinda sux but what ya gonna do..

coalkirk · Post by **coalkirk** » Thu. Jan. 30, 2014 7:31 pm

Black pipe is dirtcheap. The cost is cutting, threading and installing it. If anyone uses PEX they should have a tempering valve installed that will not let the water temp go above the level of the maximum for PEX. After all, it's plastic and will melt.

Rick 386 · Post by **Rick 386** » Thu. Jan. 30, 2014 7:48 pm

Don't know where you are located GaryFerg, but filling in your profile may lead to someone close by who had some to spare....
At least enough to get you back up and running until you fix it properly.

Yeah, I know it doesn't help right now but maybe...........

Rick

windyhill4.2 · Post by **windyhill4.2** » Thu. Jan. 30, 2014 8:35 pm

Quality pex would have to be way over 200* to melt with water . Insulate some kind of quality pipe & lay it on top of the ground to get heat back on quickly.

GaryFerg · Post by **GaryFerg** » Thu. Jan. 30, 2014 10:24 pm

i am going to patch something together until summer probably black pipe along the ground and through the window.I guess I can use foam pipe insulation on it. if I go with black pipe what is the best way to insulate it under ground? Also for 30 feet what diameter should I go?

McGiever · Post by **McGiever** » Fri. Jan. 31, 2014 7:19 am

Understand you wanting to get heating restored ASAP...but how did the system allow this extreme temp on pex to happen in the first place?
Sure adding black steel pipe allows one to ignore the root cause of the pex failure, but shouldn't the pex failure cause be understood?
For pex to rupture @ 12 psi there had to be some grossly high water temps. and that needs a remedy. And I doubt a thermostatic mixing valve can do it...mix valve needs to have cool enough water from return to dampen the supply. This water temp that ruptured the pex needed "Dumped" to a zone way before it got hot enough to rupture pex.

Did you have an ice in pipe blockage that might of caused this?
Blockage in pipe raises pressure up to match the pressure pop-off valve...30 psi.
We need to find out the cause...pex is a good product when properly installed.
Steel pipe doesn't like ice blockage either.

Post by **Rob R.** » Fri. Jan. 31, 2014 7:54 am

Something really bad happened...find out the root cause.

whistlenut · Post by **whistlenut** » Fri. Jan. 31, 2014 8:29 am

Somehow you MUST have a dump zone. No matter what you think happened, the temps went above 250 degrees. Most pex will withstand 220 in short time events, but something went crazy here. If it is a hand fed, then nothing is off limits. You have to create some means of dumping the excess heat, and resulting pressure. I'd look at your PRV and pressure reducer to the boiler as well.
Time frame? Water chemistry? History? There is more to this than a simple 'I Dunno'.

Dirty Steve · Post by **Dirty Steve** » Fri. Jan. 31, 2014 10:58 am

Is there no high limit shut off? Triple Aquastat with High and low limits? There are serious thermal protections issues here.

Freddy · Post by **Freddy** » Fri. Jan. 31, 2014 11:12 am

I guess, do whatever will get you back making heat as a temporary fix, then look to warmer weather for a proper fix. When I decided to use Pex I phoned Pex & they suggested using a mixing valve. They told me it takes less than 10 minutes of over limit temps to melt Pex. Yes, mixing valves use the cooler return water to temper the water that's headed to the Pex. Even with working limit switches on a boiler coal can easily exceed the temps needed to melt Pex.

windyhill4.2 · Post by **windyhill4.2** » Fri. Jan. 31, 2014 1:36 pm

Freddy,i've done some research on pex b4 answering your melt down claims, At 30 psi failure temp @ 268 *.These figures tell me that some thing drastic went wrong with this system to have such catastrophic failure ,pressure went berserk ?? temp went ? to mars ????? McGeiver said it best... how did this happen in the first place ???????????

OR were hot ashes left nearby & set fire to area ,melting the pex ??

Carbon12 · Post by **Carbon12** » Fri. Jan. 31, 2014 1:46 pm

Whatever happened was bad enough, however it sounds like maybe the PEX took the bullet and acted as a temp/pressure relief valve. When you say the shed was full of steam, do you mean just condensation coming off the hot water now vented into the cold air or actual boiling water steam. If it was real steam, you may want to thank the PEX for failing.

Post by **Lightning** » Fri. Jan. 31, 2014 1:47 pm

Perhaps a leak developed and emptied the boiler then hot steam would be able to melt the pex line.

kstills · Post by **kstills** » Fri. Jan. 31, 2014 1:49 pm

Pretty good PEX primer:

http://passthrough.fw-notify.net/download/405666/ ... sc_lang=en

PEX softens at 264F, melts around 330f.

I doubt it melted, but it's pressure rating drops quickly above 200f.