Thermal Expansion Valve -- in Toilet!

[CubGirl]

Hi, I just got a re-pipe to replace the old galvanized with PEX. Code calls for an expansion tank.

The plumber put in a Watts GOV80M2 that goes in your toilet. It cost $16.

After 12 hours, it wouldn't stop running and wasted a lot of water. So the tenants complained and when the plumber came to fix it (he couldn't), he told me he'd have the inspector look at the Watts one then install a regular one. I told him I wanted an expansion device. He said it wasn't necessary.

So he replaced the expansion valve today with what looks like to me a regular fill valve. I told him I was not happy and he told me it was an expansion valve. It's gray and black.

The only expansion valve that goes in your toilet that I can find out there is the Watts GOV80M2. Does anyone know of any others? The inspector today said it WAS an expansion device but when I asked both inspector & plumber the name & model #, no one could say... This is on the phone, after the fact.

Thanks...

 

[Reach4]

That Watts valve is not an expansion tank. It seems to have some kind of water hammer preventer action. If you are not getting a bang when the tank is done filling, I would not worry about it.

This thread is one of many that have discussions of expansion tanks: https://terrylove.com/forums/index.php?threads/water-heater-expansion-tank.54062/

 

[Sponsor]

 

[Jadnashua]

If your unit's water pressure is excessive, the internal valve in that Watts device will open, and that could be continuously. It's doing its job. Plumbing code requires the water plumbing pressure to be less than or equal to 80psi. IF it was, then that valve should NOT be continuously open and is indicative of some other issue (I suppose it COULD be defective, but not likely).

With a closed system, there must be an expansion tank. This is entirely different function than that Watts valve.

 

[CubGirl]

Hi and thanks... the Pressure in the home is 85 psi (so I'm told) and so these expansion devices stay on. plumber said he'd put on a Pressure Reducing valve at no cost except materials... I think an expansion tank would've been preferable. Since he wouldn't install a tank (he said no room) and the psi blows specs by 5, I have to buy a PRV... grrrrr

 

[CubGirl]

Also, the Watts serves as expansion tank too. Here this is from Watts literature. Not happy with this but I guess legally, plumber met code.

Here's what Watts says this does:

"The Governor 80-M1 discharges any extra volume of water generated by thermal expansion into the water closet eliminating the need for the installation of more expensive expansion tanks and auxiliary relief valves and their discharge lines."

 

[Terry]

Anything over 80 PSI I install a pressure reducer and an expansion tank.
I've heard of the pressure relieving fill valves, but have never installed them.

 

[CubGirl]

Yes I agree installing both is best solution.... but it looks like I'm stuck with this toilet expansion device.

:-(

 

[Jadnashua]

Terminology wise, it's a pressure relief valve, not a pressure reduction valve. Once the PRV is installed, each time the water heater runs after you've used some hot water, you'll be throwing away some water through that valve. An expansion tank is installed on the cold water supply side of the water heater such that there is no shutoff between it and the water heater. THat really shouldn't be a major issue. THen, instead of wasting water each time the WH runs, it will be stored in the expansion tank, and come out when you next open any faucet.

 

[Reach4]

Terminology wise, it's a pressure relief valve, not a pressure reduction valve.

What "it" are you referring to?

 

[SteveW]

Hi and thanks... the Pressure in the home is 85 psi (so I'm told) and so these expansion devices stay on. plumber said he'd put on a Pressure Reducing valve at no cost except materials... I think an expansion tank would've been preferable. Since he wouldn't install a tank (he said no room) and the psi blows specs by 5, I have to buy a PRV... grrrrr

So-- your static pressure is too high (higher than 80), the plumber is willing to put in a pressure reducing valve, but no room for an expansion tank. Right so far?

Then have the plumber put in the pressure reducing valve, and let the Watts fill valve handle the occasional blowoff from thermal expansion. Would still waste some water, but a whole lot less than what's happening now.

 

[Jadnashua]

What "it" are you referring to?

The Watts valve in the toilet. IN a convoluted way, it does reduce the pressure, but it is doing that in an entirely different way than a pressure reduction valve (PRV) that is used to regulate the water supply...those do NOT throw water away to perform that task.

Depending on the size of your water heater (WH), the temperature of the incoming cold water, and how hot you make it, along with how much you use at any one time, the expansion factor could cause a cup or more of water to be discharged each time. Alabama may have adequate water supplies, but take that over possibly millions of homes with one, it adds up...it is a waste, it costs in both water supply and sewage. As an emergency backup for a failing PRV, may have some merit, but it would mask that problem since you probably would not know it was happening.

 

[SteveW]

Yes I agree installing both is best solution.... but it looks like I'm stuck with this toilet expansion device.

:-(

Cubgirl:

You are "stuck" with the toilet expansion device and a PRV. Get the PRV installed.

 

[CubGirl]

Hi yes & thanks everybody! The PRV was installed Friday at their cost ($38.00) so I'm good there. But I agree that a regular expansion tank = PRV is the way to go, rather than this crappy Watts GOV80M2 Universal Toilet Fill Valve/Toilet Repair Kit that wastes lots of water.

When I asked for them to install a regular tank instead of this Watts toilet device, I was told there is no room for it. This property has a counter top height WH and there is 3/4" Pex cold main going to it with a cut off at the top of the water heater. There is little room between the cut of and the water heater to tee off to an expansion tank. Even if there were room, the tenant would not want an expansion tank hung in her kitchen. The mains are in the crawl space and I've scoured the internet to find out if the expansion tank can be installed on the cold main BEFORE the WH cut off valve.

I've seen some say no cut-off between the expansion tank and the WH. I've seen some say a cut off before and after the tank to facilitate replacement is recommended. I've seen others that have the expansion tank after the PRV and before the tank with no cut off anywhere. If the plumber would install the tank in the crawl space after the PRV & before the WH cut off valve, then the "no room" excuse is blown away.

What do you all think? Can an expansion tank be installed in the crawl space, on the cold main, after the PRV & before the WH cut-off valve? If so, it may have to be installed horizontally, unless the plumber can attach it to a joist. Is a horizontal install OK? I want the Amtrol ST-12.

Thanks everyone!

 

[Jadnashua]

The tank is supposed to be installed so that you cannot isolate the tank from it...IOW, between any shutoff and the tank. Now, that doesn't mean it won't work located elsewhere. You could always move the shutoff. The tank can be installed in nearly any position. Because it will eventually fail, when it does, it will fill up with water, so it will become heavy, so it must be supported.

 

[CubGirl]

Hi, what is IOW? And do you mean the Expansion tank is not supposed to be isolated from the WH? The main is on the ground (unlike NH, we have slabs & tiny crawl spaces in Alabama). Can it just lay on the ground on its side?? The ground would be its support... Thanks!

 

[Terry]

I install the expansion on the cold water side, sometimes near the incoming water shutoff and most of the time near the water heater. It all works.

 

[Jadnashua]

Hi, what is IOW? And do you mean the Expansion tank is not supposed to be isolated from the WH? The main is on the ground (unlike NH, we have slabs & tiny crawl spaces in Alabama). Can it just lay on the ground on its side?? The ground would be its support... Thanks!

IOW=in other words. On the ground might be okay if you placed some plastic or something underneath so it wouldn't be likely to be sitting on the potentially moist soil. You might want to ensure air could circulate as the incoming water might be cold, and it could be humid - condensation might shorten its life.

Yes, there should not be any valve between the WH and the expansion tank. As long as the valve is not closed, it would work anywhere on the cold inlet. The issue is, if that ET was isolated from the tank, it couldn't do its job, and in that case, the T&P valve on the WH would likely open to relieve the pressure. The PRV makes the system 'closed'. Water doesn't compress, so when it expands, the pressure goes up VERY quickly. Normally, it would go into the expansion tank. In your case, it gets dumped into the toilet and down the drain. As long as nobody closes the valve, it will all work fine.

 

[Terry]

There are many plumbers that install the expansion tank with an isolating shutoff for easy replacement years later.

The pressure relief valve can't be capped or have a shutoff on it.

 

[SteveW]

There are many plumbers that install the expansion tank with an isolating shutoff for easy replacement years later.

The pressure relief valve can't be capped or have a shutoff on it.

Good to know, Terry. I put a ball valve in series with my expansion tank for just such a purpose. Figured when, not if, it fails, I could isolate it while waiting to get a replacement.

I also teed in a boiler drain just so I could check the house pressure periodically, using a hose bib water pressure gauge.