Recirculating hot water
 

Fellow Villagers,

The plumbers roughed-in the plumbing for our new home in Well Point yesterday. We opted for recirculating hot water for our tankless heater. Does anyone have experience with how these things are plumbed for new construction?

From the installation manual, there appears to be two acceptable methods: using a dedicated return loop; and, a cross-over valve. The cross-over valve uses the cold water lines as a return path while the dedicated return loop is, well, dedicated to bringing the water back to the heater.

My question is, “how is the system plumbed for new construction?” Dedicated return or a cross-over valve?

The dedicated return seems better to me for some reason.

The water lines in my current Florida home run through the attic. In the summer, the cold water is very warm and in the winter is damned cold. I’ll have warm cold water year-round with the cross-over valve, I fear. (Albeit for just a short while.)

Suggest trying to contact the construction supervisor for your home.

In case not aware, Water heaters are typically placed on the garage wall near the gas meter. Usually the furthest place from point of use.

The number of pipes there could be a clue.

I wish I had contact information for any of those people!

The attached photo shows four fresh water lines originating (or terminating) at the corner of the garage. I’m still analyzing which way all the pipes go.

Kinda sounds like you are doing a custom build…..

If so call your designer (who you worked with) ….or even your realtor.

We have on on the house we bought. It has an electric WH. When we moved in the prior owners had it circulation 24/7. I am sure we saved water but it used quite a bit of electricity. I changed the timer so it circulates only certain times of the day.

When we built we also opted for a recirculating water heater. They ran a dedicated return line from the farthest point of use.

Supervisers number & name may be on the permit posted at the front of the house.

Thanks. I expect that to be the case, but I’m watching the house come out of the ground from the Florida panhandle. My eyesight isn’t quite that good. ;)

Recirculating water defeats the purpose of having tankless, as all the water lines become a virtual tank and your heater will run a lot more. You will save water but use a lot of electricity. Adding a timer as JRcorvett suggests is a good idea.

I agree. A timer is a feature in the model of tankless heater being installed. I appreciate the analogy of the how water lines effectively becoming the tank.

“Recirculating water defeats the purpose of having tankless” is not true. Recirculating water is beneficial to both a hot water tank or going tankless. A tankless gives you instant hot water at the tankless unit in the garage, it takes minutes to get the cold water out of the lines to your shower or tub. Tankless heaters you are not heating the tank 24/7 when not using/needing the water plus you still have to wait this hot water to get to your shower or tub.
We’ve had recirculating water in our last couple of houses and the most critical part of this system was setting the recirculating pump temperature correctly: too high an the pump will run constantly and keep asking the water heater/tankless heater to keep heating the water, too low of a setting, you will have colder water in the lines. I always had this pump setting a couple degrees cooler than the tank/tankless heater.

Adding a recirculating pump (in a timer) and a cross-over valve on your furthest fixture will accomplish the same thing. I checked into adding this on our build, but the $8200 cost was insane. Tho a dedicated return line buried in the slab was their method. This method should be less than $500 installed.

For those that have installed the recirculating pump with timer and crossover valve, does that cause the water in your cold water lines to always be quite warm?

Our recirculating water heater can be programmed to circulate only at certain times. It also has a “learning” mode. It’ll adjust according to your average usage.