Three Wires:
brown wire from the current sense loop goes to (1)
brown wire from the SSR goes to (5)
White wire with spade lug goes to the WHT wire (high pressure sw etc).
This will be installed on the repaired (non-warranty) unit tomorrow.
Hopefully, those Ebay parts will do the job..
The Transistor box is from a recycled garage door
Open wireless sensor.