pipes under sink?

Yesterdays new construction inspection. I found these pipes under one of the master bath sinks. had never seen this before. There was no water softener. The home is on city water supply.

to clarify. i am not referring to the black primary condensate line.

Tempering valve for the toilet?

That’s my guess to prevent the toilet from sweating.

Is that the same as mixing valve?

Site specific temperature mixing valve for the tub / shower. Just started finding these on new construction and in the weirdest places.

You can also use these when you want to keep the old 3 handle style faucets in a tub / shower for aesthetic purposes.

Keeps you from adjusting your own temp in the shower?
That seems stupid.

In my area (GTA), we find mixing valves in the basement by the water heater and not for each fixture individually.

As far as I know, water is kept at 140F in the WH tank to keep bacteria growth to a minimum and to slow down the corrosion process inside.

The mixing value reduces the temperature from 140F to a more reasonable temperature which reduces the risk of hot water scalding.

…unless I am mixing this mixing value with something else :slight_smile:

I am curious if the house has a tank less or conventional water heater?

OK ,that makes sense.:wink:

It takes the place of a built in temperature regulator found in most new faucets. When I went to put in a new 3 handle H-C-S during a full rehab, the AHJ would not allow it without a “listed antiscald / pressure balance valve” which the 3 faucet did not meet. Thus the balancing valve under the sink next to the tub.

Was there a tub next to the sink?

comparison or code reference
water tempering valves


Barry we use Union Gas here and this is a great slide show.
Notice the mixing valve in the middle.