I'm about to replace the flow switch (aka differential pressure switch?) on my 15-yr-old Vaillant combi boiler.
I'm no plumber but I think I can manage it okay.
The snag is that the plumbers' merchant supplying the switch says I'll have to drain the system before fitting the switch and refill it afterwards.
I've no idea how to drain and refill.
Can anyone help?
I'm no plumber but I think I can manage it okay.
The snag is that the plumbers' merchant supplying the switch says I'll have to drain the system before fitting the switch and refill it afterwards.
I've no idea how to drain and refill.
Can anyone help?