Any Plumbers Here? Trying to ID a part...

[JimmyTwoToes]

Installing a heat pump/hybrid WH in my shop, using a combination of Pex and copper. I came across a video showing a very clean installation and am looking to replicate it. The only piece I'm not sure of is circled in the attached photo. Is it a back-flow preventer? Not sure why it is installed where it is (cold inlet line). Is it needed? I already have a back-flow preventer on my incoming water line from the city.

 

[The Cobbler]

I would say it's a vacuum break /backflow preventer. probably a local code thing so water can't be sucked back from the heater in a vacumm situation on the supply

 

[JimmyTwoToes]

I would say it's a vacuum break /backflow preventer. probably a local code thing so water can't be sucked back from the heater in a vacumm situation on the supply

Great, thx. As long as I have a backflow preventer on the incoming line, a second one at the WH would be redundant, yes?

 

[The Cobbler]

probably. unless you local codes say different

 

[JimmyTwoToes]

probably. unless you local codes say different

Thanks again. Have never seen one installed on any WH here.

 

[rlitman]

I would say it's a vacuum break /backflow preventer. probably a local code thing so water can't be sucked back from the heater in a vacumm situation on the supply

I've never seen one installed like this, but I agree that there's nothing else that looks like that, though if it were a vacuum breaker, it's missing it's bell top (which is an important part of the system). Anyway, a vacuum breaker must be installed at least 6" higher than the highest point plumbed downstream of it. As it is, it's higher than the tank (good), but the red hot water pipe goes up from there, so this vacuum breaker does absolutely nothing [useful]. Had the water heater been in an attic with everything below it, then a vacuum breaker above it might make sense in some AHJ I suppose. In this orientation, you'd need an RPZ valve to fully protect the supply, and an RPZ should not be installed indoors. Also, a vacuum breaker itself probably shouldn't be installed indoors in a part of the system that stays pressurized. It's fine on a faucet, but used like it is here, it's a recipe for catastrophic flooding.

tl;dr: don't copy this picture. It's stupid.

 

[dogdog]

that is probably one of those air valves not a back flow preventer...
The back flow preventer I have is something like these for my boiler.

Watts 0061935; 9D M3 Backflow Preventer (1/2in)

prosupplydirect.com

https://www.amazon.com/Watts-0061888-9D-Backflow-Preventer/dp/B008FVDIQY/?tag=atomicindus08-20

maybe you have one of these contraptions... maybe wait for a real plumber to respond, no idea what your code is.?

https://www.supplyhouse.com/Rheem-SP623336-Vacuum-Relief-Valve

 

[dogdog]

This vacuum relief valve looks like the one in your picture.

1/2" Model VR Brass Vacuum Relief Valve

1/2" Model VR, Brass Vacuum Relief Valve The Apollo® Model VR Vacuum Relief valve is designed to automatically vent a system should a vacuum occur. It prevents siphoning of water from the system and/or tank collapse. Features: Brass poppet for improved strength Suitable for LP steam (15 PSIG...

www.emeraldgoldextractors.com

 

[rharman]

@JimmyTwoToes - I'd be curious for some follow-up on how that WH works for you. I'm thinking of replacing our gas unit with one of those in the semi-near future.

Where are you located (climate)?
What size is your existing/previous one?
What make/model/size is the hybrid WH?

I'm concerned about recovery time for one thing. Is yours 240V so it has the aux heating elements?

Thanks!

 

[Mr onetwo]

The vacuum breaker you asked about is fine for the application and is not missing any parts.Back in the day that particular one would have been used on low pressure steam systems because it is rated for 250 degrees F. I would use a Watts N36 for a domestic hot water heater simply because they were the cheapest option.Both operate the same.