Replacing Shower Valve Cartridge - how much water will actually be lost?

[Almighty1]

Okay, I have a question concerning replacing a shower valve catridge as I don't see a shut off valve for the water as it is probably behind all the tiles if there are any. So it seems the correct way to do this is to shut off the main water supply which till take care of the cold side and then shut off the cold water supply on the water heater but the water heater does not have a shutoff on the output side. As shutting off the main water supply basically turned off the water pressure so the water is no longer being pushed for both the hot and cold. My question is how much water will actually be lost since I would think it would only be a little because I can always just open other faucets like either the kitchen sink or bathroom sink to get rid of some of the water in the pipe and then basically the pipes will no longer have water where the shower valve is because the pipes will no longer be fully filled. Thanks in advance as never worked on something that did not have a shut off valve right before the thing I am working on.

 

[Reach4]

You could drain the WH down to low-enough.

You should remove the sediment from the WH periodically -- maybe every couple of years. This can be done by leaving the WH pressurized, and draining out several gallons. But draining water without pressure will also remove sediment, so a bonus.

 

[Sponsor]

 

[Almighty1]

Thanks @Reach4 - I used to drain the WH but I heard someone who did that with a Bradford-White from from mid-2010's actually had a leak as a result. Mines is also a 2019 Bradford-White and I did do it every two years.

 

[Sylvan]

I use the ASME section IV, which was used for boilers, so I figured it would also work for water heaters.

Remove the factory-blown-down valve and install a 3/4 brass nipple and full-port ball valve.

Install a 3/4 IPS x hose connector to the outlet of the valve.

Connect a garden hose and open the ball valve fully, then close slowly, not to hydroshock the appliance .

Remove the ball valve handle if there are children present, or place a Brass hose bib cap on the outlet, so if someone opens the valve, the brass cap won't allow it to scald anyone or flood the place.

 

[JohnCT]

Thanks @Reach4 - I used to drain the WH but I heard someone who did that with a Bradford-White from from mid-2010's actually had a leak as a result.

The drain didn't cause the leak. The heater was dying already. Ever hear of old timers putting black pepper in a car to stop radiator leaks? Maybe the drain/flush dislodged a piece of sediment stuck in a pinhole leak.

John

 

[Sylvan]

The drain didn't cause the leak. The heater was dying already. Ever hear of old timers putting black pepper in a car to stop radiator leaks? Maybe the drain/flush dislodged a piece of sediment stuck in a pinhole leak.

John

In the past, old-timers used RICE, as my former boss did. Funny smell while driving, also oatmeal worked wonders

While putting a test on a ruffing job on 104 Street nd Central Park West, there were a few pinhole leaks on the cast iron soil line.

The mechanic handed me a bucket and said Go into Central Park and get a lot of Manure. I was just starting my apprenticeship in 1969 and did not know better.

He poured it down the vent terminal, filled the line from the roof, and placed a plug at the base, sure enough, it stopped the leaks and it passed inspection

 

[Almighty1]

I use the ASME section IV, which was used for boilers, so I figured it would also work for water heaters.

Remove the factory-blown-down valve and install a 3/4 brass nipple and full-port ball valve.

Install a 3/4 IPS x hose connector to the outlet of the valve.

Connect a garden hose and open the ball valve fully, then close slowly, not to hydroshock the appliance .

Remove the ball valve handle if there are children present, or place a Brass hose bib cap on the outlet, so if someone opens the valve, the brass cap won't allow it to scald anyone or flood the place.

Thanks, will probably do this in the future.

 

[Almighty1]

The drain didn't cause the leak. The heater was dying already. Ever hear of old timers putting black pepper in a car to stop radiator leaks? Maybe the drain/flush dislodged a piece of sediment stuck in a pinhole leak.

John

This was supposedly a 1 year old BW heater. Of course anything is possible.