PIR Recirculating pump control?

[competant guy]

PIR Recirculating pump control?
Need to choose a suitable HW recirculating pump. I like the the Wilo ones as they have an auto "disinfection" cycle as well as temp management all built in.
What I need to add is an occupancy sensor, can they take an external trigger?
Also are there any other brands that have this feature do es anyone know?
Thanks in advance.

 

[stem]

I installed one on a Wilo Bronze several years ago at work. A PIR in the lobby just before the WC's and shower runs the pump that keeps the DHW circulating for I think from memory for about 1 hour after each trigger. It's connected to a relay and the second contact is used to run a central extraction fan. Once everyone has left the building after an hour both switch off.

The toilets are regularly used [there are usually about 10 to 15 in during a normal working day] so the 1 hour setting is sufficient to keep it running all day long without interruption when the building is occupied, which is necessary in this case as there is a kitchen tap elsewhere supplied by the pump as well that is outside of the PIR detection zone.

If you are planning to use the sensor just to switch the pump directly, instead of via a relay like me, make sure that the contact is suitably rated, I imagine the pump will have something like a 100W inductive load, so shouldn't present a problem, but make sure it has a suitable 'on' time for your installation.