Thread: What does this "pump" do?

Good evening

House is 3500 sqft, 1 water heater. The WH is located on the opposite side of the house from this second floor master bedroom. The hot water pressure was reduced in certain areas, but not where this was located. It plugs into a receptacle under the sink and has a timer.

It did not appear to do anything when I plugged it in. It only serves the one side of the double sink.

Thanks for your time.

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Photo attached, sorry.

Originally Posted by Dan Sandweg

Good evening

House is 3500 sqft, 1 water heater. The WH is located on the opposite side of the house from this second floor master bedroom. The hot water pressure was reduced in certain areas, but not where this was located. It plugs into a receptacle under the sink and has a timer.

It did not appear to do anything when I plugged it in. It only serves the one side of the double sink.

Thanks for your time.

Dan,

Looks to me like a circulation pump. The ones that I have seen connect the hot/cold together under a sink, typically a bathroom, connected to a momentary contact switch (like a doorbell button). When you want hot water, you press the momentary contact switch and the pump pulls from the hot water side and pushes the water back down the cold water side. A temperature sensor shuts the pump off when the water begins to warm up.

Kind of goofy, but it is sometimes more practical than running a return line for a standard hot water circulation pump.

Autocirc Undersink Instant Hot Water Circulating System ACT-E1

That looks like an AutoCirc pump: HVACQuick - Laing AutoCirc E1 Hot Water Recirculation Pumps

They connect to the hot and cold at the end of the run (farthest fixture) and when the hot side cools below a set temperature, it comes on and pumps water from the hot water side into the cold water side, which brings hot water to the faucet and keeps it there to provide hot water without wasting a lot of water to get the hot water there.

The cold side is now 'hot', but when the pump shuts off, the water cools and the cold water side will get cold water after only a short run of warm or hot water (depending on how long ago the pump last ran).

Sure beats having to wait 15 minutes to get hot water to a distant fixture.

Thanks for the information and your time.