I have three showers on second floor...

I have water temperature/pressure issues with shower 1 in particular scenarios:

1. ** This scenario has no issue ** shower 1 is being used. shower 2 is not in use. There is no issue with shower 1

2. ** this scenario has no issue ** shower 1 is being used. shower 3 is in use. There is no issue with shower 1.

3. ** this scenario has ISSUE ** shower 1 is being used. shower 2 is turned on. person in shower 1 gets cold water all of a sudden. When the person in shower 2 shuts off, everything returns (warm temp) returns to normal in shower 1.

shower 2 and 3 have pressure balancing moen valves. shower 1 is also moen valve but very old. There is no pressure balancing valve in shower 1.

FYI - shower 2 and 3 are adjacent to each other. Water heater piping wise... shower 2 and 3 are to one side of the water heater where as show 1 is on opposite side. I have two water heaters that are connected in series.

Do you think replacing shower 1 valve with pressure balancing mechanism will address my issue?

Thank you all for reading my post and thanks in advance for your advice.

 

It sounds more like a water flow issue at shower #2. More than likely that is not a low flow shower head and uses a good portion of the water pressure when on.

 

PJmax,

Thank you... I checked shower #2 with just opening the tub facet (shower head is not open). I still have the same issue in shower #1.

 

You need a flow reducer on the shower head.
Allowing the water to come out the tub faucet is even worse for water flow.

 

Hi PJmax,

do you think adjusting temp control in tub faucet will help?
https://www.youtube.com/watch?v=3EYCDcCNK3w