Biasi m90 e 24s lockout

[Microcord]

Hi

Just need some advice before i call in local plumber.
Our biasi is playing up,the central heating fires up, gets very hot then locks out, pressure also gets too high, about 2-3 bar.

Dhw works....sometimes, but very intermittent.

Have changed the 2 thermistors and purge valve.
Pump runs ok, am going to check expansion tank pressure, but if its not that then could it be pcb?

Its been a bit hit and miss for a while but its recently got worse.
Any ideas?

Thanks in advance.

 

[terryplumb]

Sounds like the heat being generated by the boiler is not being dispersed.you sure circulator is working properly ? Could be a number of other issues including blockage.when you say " central heating fires up and gets very hot " , do you mean the boiler fires up but radiators do not get hot ,then boiler goes to lock out ?

 

[Microcord]

No the radiators get very hot, so its being pumped around, all rads hot.
We live in a very hard water area,but the system was treated with inhibitor.

 

[Microcord]

The temp gauge goes to 85-90 pressure goes high and locks out

 

[terryplumb]

Ah right. Different kettle of fish then. You are going to need an engineer to visit as the control gear is not controlling the boiler temperature and the overheat stat is intervening.

 

[Microcord]

Yeh i think its over my head, yeh the overheat stat stops it, so ive turned it off completely.
Thanks for your help though,much appreciated

 

[terryplumb]

Your welcome ,good luck with it .

 

[AGAS]

but if its not that then could it be pcb?

Its been a bit hit and miss for a while but its recently got worse

JEEZS ,well that is very hit or miss don't you think , not the pcb