Hot Water Pump Recommendations

[Arca]

Hi all,

I am running new plumbing to a master bath, and would like to install a hot water loop with a circulation pump under my double vanity (furthest point in loop).

I originally was going to wire the pump into my light switch and utilize a DOM relay, but didn’t remember that I am using a dimmer.

My new plan is to install a motion detector and the pump all on a separate circuit, and still utilize the DOM relay.

Does anyone have any experience with a similar setup, and does anyone have recommendations on a good pump?

Thanks!

 

[Tuttles Revenge]

I have installed setups with push button activation but never motion sensing. Sounds like a great idea.

We install a lot of Grundfos pumps.

 

[Sponsor]

 

[Jadnashua]

You need to ensure you choose a pump body with the proper materials...potable water requires either SS or bronze pump body, not a CI one. The pump on mine only draws like 9W, but the first time it runs in the morning (it's on a timer) might take nearly a minute to bring hot water. You don't want a large pump.

Grundfos has a neat pump designed for this that uses a magnetically coupled impeller, so no bearing shaft seal that can leak.

If you insulate the lines, there's not a huge energy hit to let the system cycle itself automatically. You will need a check valve. Most of the engineered systems don't get full hot at the point of use, but run until it is somewhere in the mid-90's, but that means hot is nearby - typically seconds. By limiting the full line from becoming full hot, that also limits the heat loss and you don't need to potentially wait for the hot after you activate it. When running the lines, insulate both the supply and return lines well.

 

[Reach4]

I have installed setups with push button activation but never motion sensing. Sounds like a great idea.

We install a lot of Grundfos pumps.

Button is more energy-efficient unless you don't enter the bathroom much without washing.

 

[Fitter30]

This is a timer switch that i'm using in both bathroom for exhaust fans and you can tie the pump with it.
https://www.amazon.com/Leviton-LTB3...ocphy=9023803&hvtargid=pla-306108239205&psc=1

 

[Arca]

Thank you for the responses, everyone. I thought about wiring the pump into my fan timer, but decided against it as the fan won't always be used for vanity or bathtub use.

I have the motion detector installed with the load wired to a GFCI/AFCI at the future pump location. Works great, but wiring got a little busy at the motion detector due to its location in the circuit...had to pigtail two other branch circuits in parallel on line side. All is well, just a bit more tedious of a wiring job.

I have been looking at the Grundfos pumps and I am thinking of going with this:

https://www.bigfrogsupply.com/produ...tMW2sJPlZjqvaFG2-r1VSiNJ2PTmdn5AaAsFHEALw_wcB

I am going to set it to constant operation and the motion detector simply energizes the GFCI/AFCI. I will adjust motion detector settings once we start using the bathroom. I still have a ton of work ahead of me with the whole bedroom, but I would be happy to report back any results or issues.

 

[Fitter30]

Pump is very flexible with the different modes.