Ariston Combi boiler overpressurising

[miffli]

I have the genus 23mffi boiler which when the heating is on the pressure flies up to 3+ bar. That is almost in the red, probably would go if the heating was left on.

any ideas what this issue may be?
Best regards

 

[bazdaman]

Read the faqs its all in there, this topic has been done to death! Expansion vessel it sounds like

 

[DP]

Maybe about time the boiler was serviced

 

[miffli]

Maybe about time the boiler was serviced

It was some 6 weeks ago, I was having the trip out coming on, was leaking from the release valve, plumber tightened it right up, now sometimes it fails to work on the heating-only hot water works, but over the last 2 days the heating is working, but the pressure is going way high.

Plumber came back and changed the Thermister, this did not work, then advised the flow group needs to be changed, but I am told otherwise- plus have seen on here other possible faults, but no precise diagnosis given.

 

[bazdaman]

Time to ditch the plumber and get a heating engineer in that can diagnose faults and not guess

 

[DP]

The issue with over pressure is dealt with when boiler is serviced. The way your plumber is doing bull in a china shop thing, time you looked for someone who carries out task without guessing what needs to be done. What you got was possibly a boiler operational check NOT a service as suggested by the makers

Show him your boiler manual service section. Tells him what should be done. When it comes to changing parts, I say let him do it but do not pay unless if repair not effective