His/Her double shower - pressure balanced or thermostatic valves?

Users who are viewing this thread

poissonn

New Member
Messages
4
Reaction score
1
Points
1
Location
Quebec
Hi all, I searched through the forums, but I could only get partial answers on this one. I'm planning on building a shower with 2 independent valves & heads, similar to the picture below:

douche.jpg


There will be 1" pex coming up the wall and will tee off to 3/4" to each valve (currently not planning on doing balancing loops). The water pressure to the house is 65-70 psi so I'm not worried about flow or pressure.

However, I couldn't find a clear answer on if having two valves so close to each other absolutely requires to go for the more expansive thermostatic models. With pressure balanced valves, is there a risk for a brief scalding or very cold water snap if one person or the other suddenly close its valve or move it all the way to hot or cold?
 

Tuttles Revenge

In the Trades
Messages
2,570
Reaction score
776
Points
113
Pressure balanced and thermostatic valves are designed to prevent temperature fluctuations which could cause scalding. Either type would work in your proposed scenario.
 

LLigetfa

DIYer, not in the trades
Messages
7,023
Reaction score
442
Points
83
Location
NW Ontario, Canada
Pressure balance only corrects for changes in availability of volume. If the water temperature fluctuates from stack effect, the outcome can still scald. If the hot water is less hot, the outcome will also be less hot.
 

John Gayewski

In the Trades
Messages
2,241
Reaction score
571
Points
113
Location
Iowa
Don't get a thermostatic cartridge. You have no ability to change the temp above what someone else (the people who build them) decided was relevant.

That's just my opinion. They are just severely limited. Whereas there's more flexibility that you can determine with a regular manually limited cartridge.

I recently installed a thermostatic (wax filled) cartridge in a shower. With the water heater set at 120 I could only get 89f from thre showerhead. Had to set the heater to 140 to get 102f. Which was wasn't really sufficient either. Called the manufacturer. They told me the valves are just limited as to what you can get from them.

I'm sure there is some kind of workaround aftermarket parts or what not. Maybe adding a regulator to the cold piping, but why would someone want to mess with all that?
 

LLigetfa

DIYer, not in the trades
Messages
7,023
Reaction score
442
Points
83
Location
NW Ontario, Canada
I have a Delta shower valve with a pressure balance temperature control that is separate from the on/off (volume) valve. The thought being that I could set-and-forget the temperature and just use the on/off lever. Unfortunately, the variation in hot water temperature means I have to constantly "test" and adjust the temperature so it is not really set-and-forget.

Perhaps a thermostatic mixing valve at the water heater would be a better way to combat stacking and/or waning water temperature?
 

jadnashua

Retired Defense Industry Engineer xxx
Messages
32,714
Reaction score
1,157
Points
113
Location
New England
I've had a Grohe thermostatic valve installed for about 20-years...works just fine. Can get way hotter than I'd want, but to get there, you have to press in a safety lock. When adjusted properly, up against that stop, the temperature should be 105F, but can get MUCH hotter if you bypass that (it's simple, just press the button in while turning the control). One thing you can't get with mine, is a totally cold water stream, but that hasn't been an issue for me...I'm not a cold shower kind of guy! The coolest it seems to get is maybe room temperature, so it's always running at least a little hot into the mix.

Because of the way they work internally, you generally can get a higher gpm output of a thermostatically controlled valve, but that's not an issue when only controlling a single showerhead.

I put a thread in the tutorial section on the basic three types of currently legal shower valves.

A thermostatically controlled valve will hold the set temperature from summer to winter where the incoming cold water can vary radically, and as the WH starts to cool off until that cools off too much. Because of the humidity levels and room temperature, I find I like it slightly warmer in the winter, but don't touch the temperature control on a day-to-day basis...just use the volume control to turn the water on/off.

Given a choice, I'd install another thermostatically controlled valve. I had my first exposure to that in a Holiday Inn in London, England.
 

Tuttles Revenge

In the Trades
Messages
2,570
Reaction score
776
Points
113
Don't get a thermostatic cartridge. You have no ability to change the temp above what someone else (the people who build them) decided was relevant.

That's just my opinion. They are just severely limited. Whereas there's more flexibility that you can determine with a regular manually limited cartridge.

I recently installed a thermostatic (wax filled) cartridge in a shower. With the water heater set at 120 I could only get 89f from thre showerhead. Had to set the heater to 140 to get 102f. Which was wasn't really sufficient either. Called the manufacturer. They told me the valves are just limited as to what you can get from them.

I'm sure there is some kind of workaround aftermarket parts or what not. Maybe adding a regulator to the cold piping, but why would someone want to mess with all that?
I've never heard of nor experienced this in any thermostatic I've installed. I've always been able to get as much as the water heater will allow from a shower when installing a thermostatic..
 

John Gayewski

In the Trades
Messages
2,241
Reaction score
571
Points
113
Location
Iowa
I've never heard of nor experienced this in any thermostatic I've installed. I've always been able to get as much as the water heater will allow from a shower when installing a thermostatic..
Could be because it was an institutional shower. Leonard valve. I talked to the guy from the factory at leonard where they test them.

I haven't had the follow up conversation with him after some testing. Could be there is actually something wrong.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks