I'm trying to decide between thermostatic and pressure balaced temperature controls for my shower faucet.
I hunted around through previous postings and got the impression that thermostatic valves have a slower response than pressure balancing valves. I was told by one salesperson that the response was "1 second" which seems kind of slow to me (though he said it like it was fast). Another question I had was that if the thermostatic valve is supposed to produce a fixed temperature output, what does it do when the target temperature is impossible to obtain with the input water supply? For example, if I demand 110 degree water but my hot water pipe is full of 65 degree water, what happens? I was told by another salesperson that the thermostatic valve merely sets a maximum possible temperature. But if that's true, then when someone turns on the hot nearby, or if the washing machine gets turned on, then it seems like I'd get hit by a sudden blast of cold water. Is this true?
I got the impression that pressure balance acts faster than thermostatic. And as long as the temperatures of hot and cold remain the same, it should give the same output temperature no matter what happens around the house. Is this better than the thermostatic? Can anybody point me to information on how the pressure balance valves actually work?