Pump under bathroom basin

[JohnC]

I came across this under a bathroom sink. Can anyone tell me the reason for this device? It says pump on the device and has a timer? Owner has no idea what it’s for. None of the other bathrooms have this

Thanks

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John

[Erby]

How was the water pressure at that sink if you unplugged the pump?

[kurt]

A misapplied idea of a circulated hot water system.

[JohnC]

Water pressure was fine.

Thanks

John

[Bill Kibbel]

Here's a simple diagram that I use to show folks how it works:

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[Bain]

Here's a simple diagram that I use to show folks how it works:

Click to Enlarge

27.22 KB

Why do the instructions want the pump beneath the sink furthest from the heater? If hot water is recirculating, it's recirculating (Or apparently, maybe not.), so why is this system ostensibly more efficient than the Grundfos systems we typically see right beside heaters?

[Jim Katen]

Why do the instructions want the pump beneath the sink furthest from the heater? If hot water is recirculating, it's recirculating (Or apparently, maybe not.), so why is this system ostensibly more efficient than the Grundfos systems we typically see right beside heaters?

Typical hot water circulating systems -- those that are actually planned in advance -- use a dedicated pipe to bring the hot water back to the water heater.

These systems are for people who's plumbing system wasn't intended to have a hot water circulating system. They use the cold water pipes as a return path for the hot water. If you don't use the sink farthest from the water heater, the one that *is* farthest from the water heater won't get the benefit of the circulation.

In my experience, with these systems you trade waiting for hot water for waiting for cold water.

- Jim Katen, Oregon

[Bain]

Why do the instructions want the pump beneath the sink furthest from the heater? If hot water is recirculating, it's recirculating (Or apparently, maybe not.), so why is this system ostensibly more efficient than the Grundfos systems we typically see right beside heaters?

Typical hot water circulating systems -- those that are actually planned in advance -- use a dedicated pipe to bring the hot water back to the water heater.

These systems are for people who's plumbing system wasn't intended to have a hot water circulating system. They use the cold water pipes as a return path for the hot water. If you don't use the sink farthest from the water heater, the one that *is* farthest from the water heater won't get the benefit of the circulation.

In my experience, with these systems you trade waiting for hot water for waiting for cold water.

- Jim Katen, Oregon

Ahh, gotcha. I wasn't quite clear on why the faucets were connected to the pump and intended to take another look when I had time. Now, I don't have to.

[JohnC]

Thaks Bill for the diagram.

John

[Tom Raymond]

The instant hot water system I use is even simpler than that, my wife gets up and uses the bathroom first []

[GrantJones]

The instant hot water system I use is even simpler than that, my wife gets up and uses the bathroom first []

Ha! Yeah, my wife installed one of those. The timer is on my side of the bed instead of under the sink.

[robert1966]

I have seen a similar device with a timer as well, but it was at a wet bar. Same application I quess.