shower valves

I have a spa 4 body sprays, handheld, rainhead shower and installed a Kohler K-2971 Pressure Balancing valve with a K-728 transfer valve. The tempeture fluctuates a lot. I also have a tankless water heater. I read that pressure balancing don't get along well with tankless heater. This happens even when using one showerhead. So I think I need a thermostatic valve. But before I invest another $500+ I was want to get some opinions.

I have a thermostatically controlled valve from Grohe that seems to keep the temp very close to the setting, but I do not have a tankless system. Some designs do interact with the changing volume if it throttles to try to maintain temperature or the fact that the pressure may not be the same as the cold side.

There are a few threads that discuss this issue, but it will be interesting to see what suggestions you get.

FWIW, while Kohler makes some nice looking stuff, your results may differ - they change their designs so often, you may not find someone who has experience with things in your particular layout.

I have a tankless with a pressure balanced faucet and with non pressure balance.
I find that the temperature can vary a bit at times. A tankless will adjust temperature based on flow. If you change the setting on the valve, it tends to force the tankless to adjust itself again. I find it's better to leave the handle where it's at sometimes and let the tankless make it's adjustment. If you turn it back and forth, I'm messing with the tankless controls and how it makes it's temperature adjustment.

Does anyone have an experience with a Thermostatic with these?

MY feedback is that so many people hate the tankless. The best opinion I've heard to date is to have a small holding tank of hot water and have the tankless pre-treat that water. I think this can take out that issue. Maybe a 10 or 20 gallon reserve of sorts. We have yet to rig this up but it was an option given to me by a plumber a few years back.

hard to make out anything from this photo but I think this is kind of what the plumber was talking about.....



Photo Source

JW

FWIW, the Europeans have dealt with tankless systems for longer than we, and you may want to approach some of those manufacturer's tech support people to see if they have any recommendations. One apartment I had in Germany had one...it was not my favorite thing, but technology has improved since then.