water pump on a timer

[cory wright]

i found this water pump connected to the supply lines underneath a bahtroom sink. the pump is on a timer. i am unsure what the purpose ofo the pump and timer is. i unplugged the water pump and still had good water pressure. has anyone seen this before?

[David Bell]

The way it looks to be set up is as a hot water recirc line that is only being used at certain times to facilitate hot water to the faucet early in the morning

[Jerry Peck]

The is an AutoCirc pump: Laing Thermotech, Inc. - The Leader in Instant Hot Water Technology (http://www.autocirc.com/)

They work by pumping hot water (which is cold at first) back into the cold water line and back to the water heater, when hot water reaches the pump, the pump shuts off, leaving a little hot water in the cold water line (which cools off to cold again) and you have less time to wait for hot water to get to the faucet.

If you turn it on at the wrong time, you will briefly get hot water from the cold side until it quickly runs out (the pump does not pump much hot water into the cold side) and turns cold again.