Water pressure switch needs replacing

[stardelta]

I have Worcester Bosh 350 combi and the System Water Pressure Switch sometimes gets scale on the actuator and sticks. Naturally, boiler shuts down as it thinks "no water pressure" but pressure guage shows all ok. Got a replacement to fit but need a few tips on task involved i.e. do I have to vent anything afterwards on refilling ? Please be assured this in no way involves any modifications on the gas side (which I would never ever touch)



Regards

M.A.

[heathfield]

It'll help to write the spade (electric connection) numbers on the switch itself so you don't get confused as to which is which when reconnecting the wires. Do it so you can see two of the numbers whatever rotary position the switch ends up in. Use several turns of PTFE tape on the threads. And yes, you'll have to bleed the radiators once the system is back up and running. My 350 is on its third mains pressure switch in about 15 years.

[stardelta]

Many thanks Heathfield,looks like your'e in a hard water area too!