Tempering Valve

I just installed a Jacuzzi whirlpool tub. To help fill it, I would like to install a tempering valve at the hot water heater and raise the temperature of the WH.

Right now the water is set around 130 degrees. By using the tempering valve, I can use the existing (40 gal) WH that is only 4 yrs old. Whomever installed the WH (we just bought the house a few years ago) necked down from 3/4" to 1/2" copper right at the WH inlet and outlet. All the lines in the house are 1/2" only.

My question: If I buy the Watts 70A tempering valve, which has 1/2" connections, will this noticeably impede the flow? Or should I buy the 3/4" connection model and plumb it in. I'm not sure how much flow restriction the 1/2" model will have. There has to be enough flow to fill the tub in a reasonable amount of time. Right now, without a tempering valve, it fills fairly quickly.

Thanks
Steve

If all the supply pipes are 1/2", it probably won't make any difference going bigger...see what the pros say.



Found under many bathroom sinks in the cabinet for tempering hot water to the tub.

I'm still trying to figure out what you are hoping to achieve with the tempering valve. Some of the statements you made seem to negate what one would want to achieve when filling this type of tub.

you are already screwed

A 40 gallon heater will not fill up a whirlpool tub

you can set the thing to 170 and it still wont fill up
that tub....

forget the tempering valve,

install a 50 or a 75 gallon heater