House hot water heater.

[superj]

no, when i was still doing plumbing, we did a lot of commercial stuff and, every once in a while, we would do residential work if commercial got that slow. for home repairs, you are supposed to call the city only if doing gas line repairs or changing your gas stove or water heater so they can inspect for gas leaks

 

[superj]

i don't think anyone calls them when buying new appliances though

 

[Curious Hound]

Thousands of people do it wrong and it works. Many also end up with leaks and have to redo it several times, eventually waiting long enough for the joint to set up "good enough". I'm guilty, too. Learned a lot in that training class. Final test was a 12" piece of 3" or 4" pipe with caps on each end. After 24 hrs, it was pressurized to some high pressure (1000psi? 1500psi? I don't remember exactly) and had to hold for a certain time.

 

[Shran]

Do not use PVC or CPVC for your water heater. It is NOT the same stuff as PEX... it is cheap junk that is appropriate for drains and nothing else. If you expose it to hot water it'll degrade and crumble apart and flood your basement on Thanksgiving morning (happened to me.)

I'm on the fence on copper vs PEX. I have run a lot of both. Copper is nice for straight runs with no obstructions but repairs suck real bad when the pipe is full of water and absorbs the heat from your torch. PEX is nice if you have to go vertical through studs in a wall and it is more resistant to bursting from freezing but the fittings are really expensive and so are the tools.

If I'm doing new construction I would prefer copper, remodels could go either way, "light" remodels with not much access behind walls would probably get PEX.

 

[Roert42]

PVC will degrade over 140* F, so not acceptable for hot water application. CPVC is good to about 200* F before you have issues, and is used for hot water.

That's the main difference for use cases. That's also why the OD is different on the same size pipe. So someone cant accidently use a PVC fitting or add in a section of PVC pipe to a CPVC system.


I will agree, PEX is nice in when it comes to potentially freezing. I had some PEX under my mobile home that was exposed, I didn't know at the time, and it froze. Wrapped it in heat tape to thaw it out and it was fine. Copper would have burst.

 

[Shran]

Just sayin' I had 5' of CPVC going into and out of my water heater and then it turned to copper. Someone did a cheap ass retrofit when the water heater was replaced and it failed within 5 years at the worst possible time.

The plumber I called but did not use said that they have issues with PVC and CPVC all the time like this. It is junk and they don't ever use it. They do not consider it a "professional use" product.

Copper really sucks when it bursts. My parents have a rental trailer house that froze up when someone shut the furnace off and left for a month. Had to redo all the plumbing in the house and replace all the fixtures. Really sucked and was expensive.

 

[superj]

Thats funny the plumber said that since code was to use that for many years.

There are different types of plastic though, so maybe whoever did yours previously used a dwv rated pipe, not schedule 40 water supply pipe.

 

[Shran]

As far as I know there are three common ones - white, tan and black. Tan is CPVC from what I have seen, PVC is white, black is usually ABS I think. I had the tan stuff on there and it actually said sch 40 rated to xxx degrees and pressure right on the pipe. I suspect being a few inches away from the vent stack did not help matters either but either way it failed.

 

[Curious Hound]

Black ABS is not PVC.

There is also gray PVC. Electrical PVC conduit is gray and heavy duty PVC for industrial use is normally gray.