Just had a new water heater installed...

[Ncstatepack]

During our water heater install I was charged for a number of code-required upgrades. One of these upgrades was to add dielectric unions to the system to mate our new water heater to our copper pipes, which cost us $150. When I took a look at my setup after install, I noticed that my copper pipes were replaced by pex between my ball valve and my water heater. Would brass fittings (and a mixing valve) and pex pipes negate the need for dielectric unions? Did I actually get dielectric unions installed? Did I need them? I am in North Carolina.


Here's a pic of my setup... the pex pipe is behind the insulation

Thanks!

 

[journeyman]

I don't see any dielectric unions and it does not make sense anyway since the nipples on top of heater are already dielectrics

 

[Mr_David]

I don't see any dielectric unions.
Tempering valve a requirement there?
Do you run your heater excessively hot and then temper it down to give you more hot water?
Very uncommon here ,is why I ask. They use them only in special application here.

What was $150? the water heater or the unions?

 

[plumb_bob_square_pants]

Do you have an expansion tank? Are you on city or well water. I lived in Carolina and never seen any set up like that. If that is code compliant then that is news to me. Also if they charged you 150 for dielectric unions and then didn't put any on them on would dispute that charge. It sounds like fluff to me.

 

[Ncstatepack]

I don't see any dielectric unions.
Tempering valve a requirement there?
Do you run your heater excessively hot and then temper it down to give you more hot water?
Very uncommon here ,is why I ask. They use them only in special application here.

What was $150? the water heater or the unions?

Thanks for the reply. The tempering valve is not a requirement here, but was added to "compensate" for replacing my 65 gallons tank with a 50 gallon one. I am beginning to think this was a bad idea, as I now get a rush of cold water in the shower each time a toilet is flushed

This repair was completed via a home warranty I have. The warranty covers the water heater replacement (~$500) but does not cover any modifications or changes needed to bring it up to code. Because of this I ended up paying another ~$600 to add dielectric unions ($150), an expansion tank ($150), an expansion tank cover/jacket ($125), and a 3/4" ball valve ($95).

Obviously the company that installed the water heater inflated some of these prices to make-up what the warranty company isn't paying them for. Based on this I normally would have chosen a different company but it ended up being cheaper to have them do the work than going with a different company. After inspecting their work I am beginning to seriously question both the install of the dielectric unions and the need for them, based on there being no copper-to-galvanized interfaces.

 

[Ncstatepack]

Do you have an expansion tank? Are you on city or well water. I lived in Carolina and never seen any set up like that. If that is code compliant then that is news to me. Also if they charged you 150 for dielectric unions and then didn't put any on them on would dispute that charge. It sounds like fluff to me.

Thanks for the reply. I'm on city water.

It sounded like fluff to me in the beginning as well. Since the warranty company is paying for the install of the water heater I couldn't figure how it would cost $150 to install a $15 part into the line.

The water heater is in the garage, but the expansion tank was put in the crawl space. I'm not 100% sure why they needed to put a cover on it, but that's what the code says according to my local inspector's office. I think I'll be calling him tomorrow to ask about the dielectrics.

 

[frodo]

pex pipe is not to be used within 24'' of the water heater

the unions were a rip off.


pex is not allowed on the T&P valve either

 

[voletl]

That's an electric water heater so I don't see why you can't use PEX there's no draft Hood.

And also PEX can be used for a relief valve

 

[Debo22]

That's an electric water heater so I don't see why you can't use PEX there's no draft Hood.

And also PEX can be used for a relief valve

I don't see how pex can be used for t+p. It's not rated for 210 degrees and also pex fittings create an obstruction in the line. You need full 3/4 pipe.

 

[voletl]

Here you go...

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[Debo22]

#3 says, not be smaller than the diameter of the outlet of the valve served. Crimp fittings choke the ID of the diameter by about 1/2.

 

[SHEPLMBR]

#3 says, not be smaller than the diameter of the outlet of the valve served. Crimp fittings choke the ID of the diameter by about 1/2.

Uponor per or any other expandable pex is full flow

 

[voletl]

Okay you don't need to use 3/4 PEX you can go up to whatever size you need to as long as the outlet of the fitting is 3/4 or as SHEPLMER stated

 

[Debo22]

Okay you don't need to use 3/4 PEX you can go up to whatever size you need to as long as the outlet of the fitting is 3/4 or as SHEPLMER stated

I understand what you and Sheplmer are saying. I kept saying crimp fittings like in the Op's picture choke it down and most likely wouldn't be allowed. That being said, I've just never seen anything other than copper and galvanized that is used here.

 

[Mr_David]

It also Says you can't use flexible pipe for a t&p drain.

If I get ambitious I'll look for it. Here you can't use soft copper or copper corrugated water htr supply connectors to hook up the T&P drain.
Has to be rigid pipe. pex is not rigid.

What code book are you using?

 

[Mr_David]

Depending On your local code. It might say different.
But this 2010 California Code.


505.6 Temperature, Pressure, and Vacuum Relief Devices. The installation of temperature, pressure, and vacuum relief devices or combinations thereof, and automatic gas shutoff devices, shall be installed in accordance with the terms of their listings and the manufacturer's instructions. A shutoff valve shall not be placed between the relief valve and the water heater or on discharge pipes between such valves and the atmosphere. The hourly Btu discharge capacity or the rated steam relief capacity of the device shall be not less than the input rating of the water heater. [NFPA 54:10.28.5]

608.4 Each pressure relief valve shall be an approved automatic type with drain, and each such relief valve shall be set at a pressure of not more than one-hundred and fifty (150) pounds per square inch (1,034 kPa). No shutoff valve shall be installed between the relief valve and the system or in the drain line.

608.5 Relief valves located inside a building shall be provided with a drain not smaller than the relief valve outlet of galvanized steel, hard-drawn copper piping and fittings, CPVC or listed relief valve drain tube with fittings that will not reduce the internal bore of the pipe or tubing (straight lengths as opposed to coils) and shall extend from the valve to the outside of the building, with the end of the pipe not more than two (2) feet (610 mm) nor less than six (6) inches (152 mm) above ground or the flood level of the area receiving the discharge and pointing downward. Such drains shall be permitted to terminate at other approved locations. Relief valve drains shall not terminate in a building’s crawl space. No part of such drain pipe shall be trapped or subject to freezing. The terminal end of the drain pipe shall not be threaded.

 

[voletl]

Considering the original poster is from North Carolina and as far as I know North Carolina is IPC I'm using IPC code

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