controlling two Heatpumps

[mac_J]

Would like advice and comments on setting up following electric control for two heat pumps

I wish to send a start signal to two 10kW heatpumps simultaneously.

One of the heatpumps would have delay start built in, to avoid excessive current draw

One of the heatpumps would kept running until water temperature reached 45C, the other would cut out at 48C.

All advice appreciated

Regards

Johnf4@mac.com

[mad fridgie]

Install a latching relay, when both stats are open break the latch, only when both stats are closed make the latch

T1 on and T2 on = to energize latch "On"
T1 off and T2 on = On
T1 off and T2 Off = Off.

Or even buy a smart relay (baby PLC) and do your timer in here as well