Harwil 46 mm with cable

This Harwil flow switch, with a half-inch thread, is used in the Astrel Easy Heater, among others. It screws into a threaded socket, often on the heater union.

There are several versions of this Harwil flow switch, all bearing the reference Q-12DS-C, with different thread diameter lengths and sizes (see diagram). This is the "Large" size, with a 1/2" thread and a 46 mm body length. This flow switch is not compatible with the straight or tee Harwil flow switches (which are in "Medium" size), although it has the same reference.

Dimensions ("Large" size, in red on the diagram)
Thread diameter: 21 mm (1/2-inch MPT)
Reed length: 46 mm
Total length: 75 mm

Part numbers
Astrel: PFGMA0AF0001
Harwil : Q-12DS-C2/2/6M/

Installation instructions