when i turn on my boiler it comes on and then after some hours it turns off showing an S75 code. No hot water and no heating. After trying torelight it sevaral times it comes back on. What could be the problem?

nassib, November 2010

My sister always turns her boiler off and in doing so, the pressure drops, you can connect a silver flexi pipe (which should be under your boiler usually hanging over the pipes) to connect the valves underneath, then slowly open both and the pressure will rise. Be careful to only raise it slightly as when it is in use the pressure will build up and shouldn't be above the line guide.

Karl, January 2022

F75 (not s75) relates to one of two things:
System pressure switch not functioning (often due to dirt in the system)
or:
Problem with the pump.

Most likely, pressure switch especially if it's a salmon pink colour.

Carefree, November 2010