cpvc pipe & on-demand water heater

[johnnymac96]

We are currently in the middle of a whole-house remodel, part of the job specs was to replace all of the 40 yr old galvanized pipes with CPVC (per recommendation of the subcontracting plumber) and also install an on-demand external heater.

Today we were red-tagged during the rough-in inspection because apparently CPVC is not code-approved for use with on-demand heaters - our plumber claims to have installed a lot of these heaters with cpvc in non-incorporated areas of the county where inspections are not required, and claims he has never had one fail, but this is his first time to install one in the city and be inspected.

My GC sounded like he was genuinely upset with the plumber and assured me that the problem was entirely the plumber's problem to fix and no one else's, so I am not worried about any additional cost to me. What I am worried about is the delay.

The plumber is assuring everyone that the water heater is compatible with the cpvc ratings and that he will appeal to the inspector's office for a waiver of the code based on the individual specs and ratings and that it will take "2-3 days" to get the letter from the city. The problem is that we can't put up any drywall or insulation until this gets resolved.

So my question is, is this waiver likely to happen, and if it does, how much of a delay am I looking at to find out? If the waiver is not granted, the plumber is going to have to remove all of the downstream CPVC and replace it with copper or pex. We're talking about 100-120 feet of piping that is downstream of the water heater. It didn't take him long to put it in, I suspect it won't take him long to take it out and replace it.

On a more general level, is this red-tag a big deal? Are these heaters really compatible with the CPVC or should my wife and I insist that he just go ahead and install copper and ignore trying for an appeal? I am sure that just asking him to go ahead and redo it will entail some extra costs, but I am also a bit worried that even if we do get a waiver, the code was written for a reason and there is some risk of the pipe failing at some point.

Any feedback is appreciated - thanks!

 

[Jadnashua]

First thing...read the installation manual. The code says (normally) install per the manufactuer's instructions, and if it is not stated, then to some other applicable code.

I checked the installation manual for a Bosch unit (others are likely the same). It reads "Plastics or other PEX type plumbing line materials are not suitable for connecting directly to the water heater." Now, you could probably just do a transition to whatever maybe a foot or more away from the heater, but you can't connect it directly to it. IMHO, it is also a requirement to install a tempering valve on the output. I'd make the piping up to and including that copper, then transition, if you wanted.

 

[Sponsor]

 

[hj]

code

Codes are often more political than practical, so not being an approved item may, or may not, be because of the material itself. Variances can happen in minutes or they can take days or weeks. It depends on how adamant the agency is about not wanting to approve the pipe. A properly operating on-demand heater is no different than a tank type, since both are sending thermostatically temperature controlled water into the piping. Neither type should have plastic attached directly to the heater. But this is standard for any heater, even swimming pool heaters have this prohibition even though they are operating at much lower temperatures and pressure. It the heaters thermostat is set properly, and is working properly, then a tempering valve is not necessary.

 

[Got_Nailed]

In my city in VA you have to use copper between the heater and the tempering valve. After the tempering valve it is your choice. So you’re looking at under an hour of work to install the tempering valve and a foot of copper.

This might not be true where you live. Pick up the phone and call the inspector and ask if this would be good for the inspection. You might want to remind the inspector that look below. This is off the http://www.ppfahome.org/cpvc/index.html web site. After a tempering valve you will be in spec’s of the CPVC




USES/APPLICATIONS
CPVC piping which is suitable for hot and cold water distribution has a 400 psi pressure rating at room temperature, and a 100 psi pressure rating at 180 F.