Water heater expansion testing

[pizzamonger]

If I have a closed loop system with a pressure regulator, how can I test to see if the water heater is causing a problem with expansion that is increasing the pressure? Will I be able to read it any time with a pressure meter on a hose bib? Do I need to create a special condition where the problem would be more evident?

 

[Reach4]

To test with a pressure gauge, take a hot shower or bath. Turn off all water use, and do not flush a toilet or otherwise use water.

While the water heater is still recovering, watch the gauge.

Alternatively, get a gauge with a "lazy"/"tattletale" hand. That records the peak pressure. Those can be affected by vibration.

 

[Sponsor]

 

[pizzamonger]

Got it. So use a ton of hot water, and then watch as the water heater re-heats the water. So my plan will be to put the meter on the hose bib in the front of the house. Enjoy a long hot shower, and then stand in the front of the house with my towel on for 30 minutes or so and see how high it goes. Sound ok?

 

[Reach4]

Got it. So use a ton of hot water, and then watch as the water heater re-heats the water. So my plan will be to put the meter on the hose bib in the front of the house. Enjoy a long hot shower, and then stand in the front of the house with my towel on for 30 minutes or so and see how high it goes. Sound ok?

Maybe use the hose bib in the back of the house. Or use a laundry tap or the water heater drain, and stay inside.

In fact, it is possible that the pressure outside and inside is different. That could occur if you have a PRV, but the hose bibs get their water before the PRV.

 

[pizzamonger]

The hose bib is after the regulator. I did some hot dishes, then I took a hot shower. My pressure is about 62.5psi with the new regulator. When I cam out of the shower it was still reading 62.5, but at some point it had spiked to 70psi, indicated by the max pressure part of the gauge. Now I will watch for a while to see if it increases as the water heater does it's thing.

 

[pizzamonger]

Strangely the water heater doesn’t seem to care that I used a lot of hot water and I don’t even think it’s running.

 

[pizzamonger]

Yep, no good. Spiked at 120 at some point. Some connections that aren't too tight are leaking a little here and there. What can I do until I get the pressure tank on? Leave a faucet open a little bit? Not use hot water?

 

[pizzamonger]

I only was able to see maybe 5oz of water that came out. Mostly on the connection from the cold water line to the water heater, where I knew it had a little issue. This was definitely more water than I have ever seen in that spot before though. Before it would get wet if I turned the water on and off a lot, this time it had standing water. I hope it didn't bust any other connections anywhere. I've turned the water heater down and will not use hot water until I can get the expansion tank on. How bad is one expansion testing of 120psi on an old system? I'll check the water meter tonight before sleep and again in the morning to see if I'm losing any anywhere.

 

[Reach4]

Some people go for years letting the T+P release water at 150 psi.

What kind of connection is dribbling at 120 PSI?

 

[Jadnashua]

Toilet fill valves are a common place where excess water pressure can be relieved and they often don't show any leaking since it just goes down the drain.

Most of the companies that sell ET also have a calculator on them to show you the amount of expansion based on the starting temperature, ending temperature, and volume it started with. It's a fixed, known constant, and you can do the math yourself if you wish.

 

[pizzamonger]

Some people go for years letting the T+P release water at 150 psi.

What kind of connection is dribbling at 120 PSI?

Im hoping it’s just the top of this connection. It’s the cold water line so will need work for expansion tank anyways. The toilet is new so hopefully did not bust that seal. Im watching the water meter overnight. The pressure gauge leaked a little at 120psi. Hard to say what else that might have woke up in the walls or under the house. Scary to check the gauge and see it was 120 and then find the water coming out of seals.

 

[pizzamonger]

Where should the pressure tank be mounted?

No good spot because the door is right there. Can it sit on the water heater? I know it’s better to have it vertical than horizontal. This rainbow cold water line makes it hard to envision.

 

[Reach4]

It does not have to be very close to the WH. Let's see the supply line where it might be handy to mount.

 

[pizzamonger]

Where should the pressure tank be mounted?

No good spot because the door is right there. Can it sit on the water heater? I know it’s better to have it vertical than horizontal. This rainbow cold water line makes it hard to envision.

View attachment 48883

 

[pizzamonger]

What do you think?

 

[Reach4]

I would try to add some support. It looks like this sits atop some not-well-supported 1/2 inch copper. Maybe some Perforated Metal Hanger Strap lifting toward the ceiling.

Set the air precharge to your normal pressure 62.5 or maybe a little higher. The tank should normally be empty except when the the water expands.

 

[Master Plumber Mark]

you had better put a leg under that expansion tank
down to the water heater. or tie it off and hang it from the rafters above it ..
the weight could cause too much stress on the pipes---

if were ever to break off then
you will know the true meaning of plumbing problems.....



n...

 

[pizzamonger]

I'm trying to adjust the regulator. No matter how tight I put it or how lose the pressure on the house is 62.5???

Is a wooden stand on top of the water heater ok by the book?

 

[pizzamonger]

Now it seems stuck at 80psi, which is around the pressure before installing the regulator. Guessing the regulator is not working. And guessing the pressure tank is full, since I set it to 65psi. I had a licensed plumber put everything in. Pretty frustrated right now.

 

[pizzamonger]

The guy testing and setting the regulator is a doofus. New pressure house pressure set to 55psi. Pressure tank set to 60-65psi. Will monitor overnight with gauge on utility sink. And dream of building some type of support for the pressure tank since I was left hanging like that.