Glow worm flexicom F9

[johnad]

Hopefully someone can help me out with my boiler problem
I have a glow worm flexiecom 24 cx.
A few days ago first thing in the morning the boiler was locked out flashing the F9 code, after some Internet searching I believe this to be a preasure problem ?
I then opened the filling loop and uped the preasure to 2 bar reset the boiler and it fired up and everything was ok for a few days ,
This morning the same thing so checked the preasure it was still on 2 bar so I reduced this to 1 bar and the boiler would just make a few noises and lock out again with F9 flashing,
So I upped the preasure to 2bar again and it's now all working anything under 1.8 bar and it stops so after finding some info on the internet I'm thinking it must be the preasure switch as the pump runs fine at a higher preasure.?
So before I pay out for a new switch are the any other possibilities ?
And if the switch is at fault would it still display the correct preasure on the display panel ?
Any advice please...
[/quote]

 

[johnad]

Just another point guys
This happends over night when the heating / hot water has been off for a few hours.
When I get it running its fine all day but now and then needs resetting in the morning.

 

[GuessMan]

You will need a new pressure sensor, but the expansion vessel will need to be checked also. This is what may have goosed the sensor.