Water heater fitting?

[Marshfly]

A couple of months ago, I was driving some washboard roads with my Lance 850 to get to a remote campground. Get parked and leveled, turn on the water pump, and immediately hear water in the cabinet. Turns out that the 90 fitting going into the water heater was installed too close to a drain pipe and vibrated against it. It snapped off clean flush with the water heater. I'm pretty sure that I can get rest of the fitting out and find a replacement so I can reroute it further from the drain line. My question is, what glue or caulk should I use to install the new fitting? It looks like there's some kind of caulk there now.

Here's a pic.

[Marshfly]

I actually dumped the PEX and used a 1/2" nipple on each end and a braided stainless toilet connector to get rid of half of the connections and make sure that there were no plastic fittings to worry about and insulate the plastic valve with the flexible braided hose.

[Marshfly]

ckwjl wrote:
It looks like the nipple at the cold water inlet of your water heater snapped. This nipple is a threaded check valve made of black plastic. The hot water outlet also has one, just turned in the opposite direction. My hot water outlet check valve cracked and I broke it completely off trying to remove it with a wrench. Get a $9.50 Pipe Nipple Extractor Set HDX167 at Home Depot. Harbor Freight has a similar set. Getting the check valve out with this is a breeze. I replaced the plastic check valve with a brass one I found at my local RV supply store.

This was exactly it. And that extractor worked great. Now to piece together the PEX from the bypass valve to make sure this doesn't happen again.

[ckwjl]

It looks like the nipple at the cold water inlet of your water heater snapped. This nipple is a threaded check valve made of black plastic. The hot water outlet also has one, just turned in the opposite direction. My hot water outlet check valve cracked and I broke it completely off trying to remove it with a wrench. Get a $9.50 Pipe Nipple Extractor Set HDX167 at Home Depot. Harbor Freight has a similar set. Getting the check valve out with this is a breeze. I replaced the plastic check valve with a brass one I found at my local RV supply store.

[AnEv942]

Well im 180° out, Standard pipe dope, the 'gray' stuff or any oil base will soften plastic, however there are several types of pipe joint compound suitable for plastic threads, they will say so. I use Oatey (great white w/ptfe). Rectoreseal amoung others-read the lables

Useful where tape wont seal or reusing fittings. Over torquing to get a seal (#1 failure on plastic threads is deformation) less likely than where tape is used. My first choice would be Teflon tape but in the camper 'dope', especially plastic to plastic threads or where vibration likely or thermal expansion/contraction like on water heater. All of our threaded water plumbing joints were installed with pipe joint compound, usually white. We've had no failure due to it. Weve had no leaks I assume due to it.

Coarse Ive not stayed an any motels that would give me the expertise of a professional, just my opinion. But that fitting not in line with where it should be causes me to think wouldnt have mattered what it was sealed with...

[Marshfly]

The fitting didn't fail. The 90 was hard against the black drain pipe below it and it snapped due to constant pressure from 30 miles of washboard.



Also, I'll have to look at it again but I thought it was a smooth fitting glued in there. I haven't pulled the stub out yet so maybe it's not. If it is threaded into the water heater, that makes this job easy. Is that normally the case?
I'd go look but the camper is in my warehouse across town.

[Old-Biscuit]

nomad297 wrote:

Dakota98 wrote:

nomad297 wrote:

Vet Man wrote:
Teflon Tape

This is correct. NEVER use pipe dope/thread compound on any plastic or rubber plumbing parts -- it will degrade the plastic and make it very brittle.

Bruce

Wouldn't either one of these be suitable ?

Dope

Tape

No. Never, ever use a compound on plastic or rubber plumbing parts, especially threads. Believe me. I've been fixing these mistakes for over three decades now.

Bruce

Which is why that plastic fitting failed due to vibration........factory used DOPE when doing install

[nomad297]

Dakota98 wrote:

nomad297 wrote:

Vet Man wrote:
Teflon Tape

This is correct. NEVER use pipe dope/thread compound on any plastic or rubber plumbing parts -- it will degrade the plastic and make it very brittle.

Bruce

Wouldn't either one of these be suitable ?

Dope

Tape

No. Never, ever use a compound on plastic or rubber plumbing parts, especially threads. Believe me. I've been fixing these mistakes for over three decades now.

Bruce

[Dakota98]

nomad297 wrote:

Vet Man wrote:
Teflon Tape

This is correct. NEVER use pipe dope/thread compound on any plastic or rubber plumbing parts -- it will degrade the plastic and make it very brittle.

Bruce

Wouldn't either one of these be suitable ?

Dope

Tape

[nomad297]

Vet Man wrote:
Teflon Tape

This is correct. NEVER use pipe dope/thread compound on any plastic or rubber plumbing parts -- it will degrade the plastic and make it very brittle.

Bruce

[Vet_Man]

Teflon Tape