Tempering valve feeding to anti-scald shower

David Thomas

Hey, after sending many people over here from FHB's Breaktime forum, I want some advice from the more experienced folks.

DHW, RFH, and a bit of forced air hydronics off of one HWH. So I run the HWH hot. But then through a tempering valve (Watts 120-160F) for all plumbing fixtures.

The Peerless anti-scald shower valve, even when set to its hottest, wants pretty hot water. Possibly to balance out the 37-39F incoming cold (Kenai, Alaska).

When I do that, the kitchen sink feels like a scald hazard for my pre-schooler.

I could put another tempering valve (Watts or Taco 5000) under the kitchen sink and continue to run the whole house HW pretty hot.

BUT INSTEAD - What if I put a anti-sweat valve (50-50 hot-cold mix valve for toilets) on the cold shower feed? Then dial the whole house tempering valve down to 115-120F?

Is that anti-scald shower valve fine with 120F on the hot side and 80F on the cold side? Must happen in Phoenix, right? And I think it would make the shower less touchy than it is now balancing 38F versus 140F inputs.

Any thing I'm missing here? Many thanks in advance. -David

bigugh_4

\"Cascading\" Mixing valves

An old trick. especially in photo labs to control water temperture exactly. Just use the valves within their respective temperture ranges and you should be fine. "Cascading" means contolling the input of a second tempering valve with the first valve. The manufactures information, "curves" should be as close to the middle as you can possibly get. Water at 120*F will burn second degree. 110* F water is too hot to "normally " bathe in. Gallon per minute considerations may have to be looked at also. You'd most likely want your tub to fill quickly. or shower to wet you nicely. good luck
bigugh