PSI and leaking faucet question

Help Support Plumbing Forums:

SurferChicUSA

New Member
Joined
Dec 10, 2018
Messages
1
Reaction score
0
Location
Southern California Hi-desert
Hi guys! Please bear with me while I try to explain my situation:

I’ve been a full-time RV’r for over 25 years, in a total of four vehicles. The plumbing in an RV is similar to that in a stationary home. I’ve installed faucets in my rv as well as in real homes, with no problems (kitchen faucets, bathroom faucets, outdoor faucets, etc.. No leaks, nothing out of the ordinary.

Here’s the problem: my friend impulsively bought an RV, without giving me a chance to check out all the amenities, like the electric, the plumbing & appliances (incl the hot water heater). Since the stock hot water heater in her rig didn’t work, she had another friend install an after market hot water heater that is not rv-specific, but that is supposed to be applicable to an rv/tiny house/etc.

( it’s a Bosch Electric Mini-Tank Water Heater Tronic 3000 T 7-Gallon (ES8) - Eliminate Time for Hot Water - Shelf, Wall or Floor Mounted)

Facts that I think are important for troubleshooting:

PRIOR to the installation of the Bosh hot water heater, there were NO WATER LEAKS in the RV.

The water inlets for all RV’s have built in water pressure regulators set at 50 PSI.

The built in water pressure regulator on the Bosch is 150 PSI

My friend wanted a new faucet installed because she broke the little diverter knob that gets pulled to make the shower head work.

The original faucet did not leak prior to Bosh being installed.

Once the hot water heater was installed, ONLY the hot water side leaked (where the water line is attached to the faucet).

So I removed the old faucet, and installed a new faucet.

I used the old (original) 1/2 inch compression fitting to screw on the COLD water supply to the new faucet. It went on easily and did NOT leak.

I did the same thing with the HOT water - original hardware screwed on easily to the new faucet. Leaked like crazy.

Since only the HOT water leaked with the old faucet AND with the new faucet, using the old fittings, I went and bought my favorite “go to” - brass Shark Bite fittings.

I used the BRAND NEW shark bite fitting on the HOT side and it STILL LEAKED.

Cold side: no leaks with old faucet/old fitting, no leaks with new faucet/old fittings.

Hot side: no leaks prior to hot water installation. After hot water heater installation, the hot side leaked with old faucet/old fitting, new faucet/old fitting, & leaks with new faucet/new fittings.

My theory is that the water pressure leaving the hot water heater is too high for the pipes in the rv, since the rv water inlet is set at 50 PSI & the Bosch is 150.

The guy who installed the hot water heater is an apartment handyman, not a licensed contractor or plumber. He said that the 150 PSI mentioned in th Bosch specs just means that the Bosch is “capable of accepting up to 150 PSI,” but that whatever the pressure is entering the hot water heater is the same amount of pressure exiting the heater.

He seems to think that using a braided supply hose on the hot water side will stop the leak. Not one of my four RV’s have EVER needed a braided supply hose for the hot water faucets. All of my hot water faucet lines are connected exactly like the cold water faucets with the same fixtures. I could switch my cold with my hot and there’d be no leaks. He’s not taking into consideration the fact that it’s only the hot side leaking and that it only started leaking after the hot water heater installation.

In my little brain, I see the hot water heater as being the cause of the leak because it seems to me that there is 50 PSI coming in to the rv, then the water enters the hot water heater and comes out at 100 psi higher than the rv is designed for.

Am I right, or is it just a coincidence that ONLY the hot water side leaks even with new fittings and a new faucet????

The guy who installed it thinks that adding the braided hose will solve the problem.

I have two theories—

1). that an in-line water pressure regulator set at 50 PSI added after the hot water heater (to step down the psi from 150 back to 50) will solve the problem.

OR

2). The fact that he did not install a hose to he pressure relief valve to allow excess pressure to escape could be causing the pressure to be too high, and since the excessive pressure isn’t escaping via the pressure relief valve, it is being forced out the end of the line, which is where it’s leaking.

Does anyone have any thoughts on this????

Thanks in advance!!!
 

voletl

Well-Known Member
Joined
Dec 17, 2014
Messages
800
Reaction score
249
Location
New York
Did you hook a pressure gauge to a hot line to actually test your theory? If your hot water pressure was 150 psi all the faucets in your rv would be dripping like crazy.

Also the pressure relief vavle doesnt need a hose to be attached to it to work. If it needs to pop it will pop.
 

Diehard

Well-Known Member
Joined
Aug 19, 2017
Messages
2,640
Reaction score
469
Location
North Reading, Mass.
If it did have a PRV set for 150PSI it would simply remain wide open if being fed with 50 psi pressure. A PRV can't boost pressure. The 150 psi is likely a working pressure rating.

You mentioned that they, "did not install a hose to he pressure relief valve to allow excess pressure to escape" implying they may have plugged it. If so, that may be the cause of the suspected elevated pressure.

Did you try NOT turning the heater on and then checking for leaks? Although the best time to have tried that would have been after making all your new connections. If the water is not heated then the pressure wouldn't be any higher, eliminating the association to the new heater.
 
Last edited:

Mr_David

Easily Amused
Professional
Joined
Jan 11, 2010
Messages
4,170
Reaction score
1,058
Location
Santee,Ca,
The water inlets for all RV’s have built in water pressure regulators set at 50 PSI.
ALL !! Are you sure?
I had an RV and when I connected to a water supply I had to use a reducer on the hose I was connecting with.


The built in water pressure regulator on the Bosch is 150 PSI.
Are you sure it's a regulator you're talking about or a safety relief valve.


I used the old (original) 1/2 inch compression fitting to screw on the COLD water supply to the new faucet. It went on easily and did NOT leak.
I would say you just got lucky .

I used the BRAND NEW shark bite fitting on the HOT side and it STILL LEAKED.
Cold side: no leaks with old faucet/old fitting, no leaks with new faucet/old fittings.
Hot side: no leaks prior to hot water installation. After hot water heater installation, the hot side leaked with old faucet/old fitting, new faucet/old fitting, & leaks with new faucet/new fittings.
What specific fitting did you use?

My theory is that the water pressure leaving the hot water heater is too high for the pipes in the rv, since the rv water inlet is set at 50 PSI & the Bosch is 150.
If inlet pressure is 50 psi the entire system is 50 psi. Heating the water, as previously mentioned, can increase the water pressure but that would be an increase in both the hot and cold system equally.

The guy who installed the hot water heater is an apartment handyman, not a licensed contractor or plumber. He said that the 150 PSI mentioned in th Bosch specs just means that the Bosch is “capable of accepting up to 150 PSI,” but that whatever the pressure is entering the hot water heater is the same amount of pressure exiting the heater.
He is correct.
Heating the water can increase the pressure, but again, the pressure would increase in the entire system.


He seems to think that using a braided supply hose on the hot water side will stop the leak. Not one of my four RV’s have EVER needed a braided supply hose for the hot water faucets. All of my hot water faucet lines are connected exactly like the cold water faucets with the same fixtures. I could switch my cold with my hot and there’d be no leaks. He’s not taking into consideration the fact that it’s only the hot side leaking and that it only started leaking after the hot water heater installation.

What is going into the faucet? Is there a neoprene gasket/cone washer on a copper tube and a brass nut. did you try changing the washer.
how is it connected to the faucet?


In my little brain, I see the hot water heater as being the cause of the leak because it seems to me that there is 50 PSI coming in to the rv, then the water enters the hot water heater and comes out at 100 psi higher than the rv is designed for.

Am I right, or is it just a coincidence that ONLY the hot water side leaks even with new fittings and a new faucet????

The guy who installed it thinks that adding the braided hose will solve the problem.

I have two theories—

1). that an in-line water pressure regulator set at 50 PSI added after the hot water heater (to step down the psi from 150 back to 50) will solve the problem.

Not the solution, as previously pointed out

OR

2). The fact that he did not install a hose to he pressure relief valve to allow excess pressure to escape could be causing the pressure to be too high, and since the excessive pressure isn’t escaping via the pressure relief valve, it is being forced out the end of the line, which is where it’s leaking.

Hope he didn't put a plug in it. That is a safety valve, designed to open at 150 psi so the heater does not explode.

Does anyone have any thoughts on this????

Thanks in advance!!! You're Welcome
 
Top