Plumbing Question

[skyking1]

Yes, I'm more familiar with copper piping coming right off the top of the hot water tank and going right out.

 

[target2019]

It was dumping out the wall. It wasn't cut off, just never glued. The glue appears to have been missed during the rush of the build.

If I could summarize what we've come up with:
- For OP's housing area, code apparently allows a PRV in lieu of an expansion tank for hot water expansion
- This device is under the sink and is very simply plumbed with an exit straight out the wall

And here's my editorial: this is cheaper than an expansion tank and a plumber can plumb this up in 10 minutes. 5 minutes to cut the hole in the wall, 5 minutes to Pex crimp and tighten the "drain" line. Apparently for this builder, 10 minutes was too much and they did it 9 minutes by not gluing the drain line. I'm joking, but you get the drift.

This application is not at all common in North America and almost stands out as a wild duck.

I think you are painting the right picture here. It also may help with cleanout, water hammer, and plumber's butt crack. Last item of course is my attempt at a joke.

This is dredging up work memories. I used to examine drawings of US Navy ship systems for parts and what to replace them with (like the Zorn PRV, water hammer arrestors, and other valves. )

 

[Dean56]

The reason I responded is because I have this exact same setup in my house which was built in 1998.
I live about 20 miles north of OP in Georgia. Thermal expansion tanks were not required (not even sure if they were around in 1998). But, this is how the plumbing system was protected inside the house in case the water pressure increased above the allowable limit. BTW- the whole house was plumbed using copper pipe.

The water heater has it's own PRV which exits the house in it's own pipe.

 

[JoeWras]

Here in NC, my municipality (and many others) started putting in backflow/check valves at the meter around the late 90s. They made a big deal about us installing water heater expansion tanks to save our plumbing. Before they did this, our expanding hot water pushed against the city water. This would end when they did the installation and warned we'd have some blowouts if we didn't install the tank.

I installed my own around 1999. I remember before I did that when I turned on my hot water, the water just flowed out like crazy. You could really see that the pressure increased.

Georgia seems to have taken a different path.

Expansion tanks are not new. They were integral to many hot water heating loops. Here's a 1996 NYT article that mentions them: HOME REPAIR;How to Keep Your Hot-Water Heating System Up and Running (Published 1996)

 

[Jerry1]

How does one figure out the water pressure of the house? I’m having a different issue and need to know my water pressure.

 

[JoeWras]

Buy a simple pressure checker that fits on a hose spigot. Turn off your hot water at the tank and drain a good deal out of the hot water lines by turning on hot water at a few sinks for a minute or so.

Then put the tester on the hose spigot and see what you get when you turn on the spigot.

I recently bought this pressure tester and I like it a lot. It works better than my old one and as far as I can tell, it is accurate.

https://www.amazon.com/gp/product/B0BFCN2XWZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

BTW: an advanced exercise is to do the above first, then turn on your hot water as normal and let the water heater reach maximum heating without you turning on any faucet or appliance. The tester above has a nice "max" needle to help with this.

In this way, you can check the pressure differential between hot and cold water. When I have my expansion tank disabled, I see a difference of up to 30 psi, but usually about 20 psi. It is not insignificant.

 

[ERD50]

Buy a simple pressure checker that fits on a hose spigot. ....

I recently bought this pressure tester and I like it a lot. It works better than my old one and as far as I can tell, it is accurate.

https://www.amazon.com/gp/product/B0BFCN2XWZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

View attachment 51471

BTW: an advanced exercise is to do the above first, then turn on your hot water as normal and let the water heater reach maximum heating without you turning on any faucet or appliance. The tester above has a nice "max" needle to help with this.

In this way, you can check the pressure differential between hot and cold water. When I have my expansion tank disabled, I see a difference of up to 30 psi, but usually about 20 psi. It is not insignificant.

Thanks for that link. I had cobbled up a pressure gauge and a hose connector to check water pressure, but that reset-able MAX needle is what I really need.

There was no expansion tank on our water heater (home built in 2007), and the water heater lasted 15 years (about as much as one can expect, though I've had them last much longer), so I'm not sure an expansion tank would make much difference. But I'm curious to see what I do get.

Also, I would not expect a difference between hot/cold unless there is a check valve on the inlet of the water heater. I'm not sure how common that is?

 

[ERD50]

I'll also add - our water heater was ~ 30 YO and still working fine on our old home on a well. Water softener for the hard well water, never replaced the anode rod except when we first moved in (sulfur smell, changed it out for the alum-zinc type, but never replaced after that - couldn't get it out and was afraid I'd break something, so left it).

With a well, there is an expansion/storage tank, so we should never have a high pressure from water heater expansion - unless the water heater had a check valve. But I figure the benefit of that exp tank might be offset by cycling of the pump, between 45 PSI to 60 and back to 45 several times a day. Seems that would be a long term stress on the tank, a small fluctuation every time?

 

[JoeWras]

Yeah, typically if you have an expansion tank somewhere, that's it.

The expansion tank is not just to protect the water heater. It is to protect everything. Every joint, every toilet flush valve, etc.