Biasi Combi Boiler DHW working but no central heating!

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Hi,
My Biasi RIVA COMPACT HE MK2 M96A.24SM suddenly has a fault.
I have DHW but no central heating. Boiler fires up on the taps but not on CH.
I have bled my radiators, the water pressure is at 1 bar, slightly high I know and I've left the CH on for 2 hours but still won't come on. Thermostat is fine. Fuses are fine. I usually turn the central heating on via the thermostat when I need it.
Normally when I turn on the hot water tap I can hear a thud which is I believe is the divertor valve switching position via the actuator, not now. After disconnecting the actuator I can see that the pin is always in the forward/out position. I am able to manually push the diverter valve in and out.
When I turn on the boiler via the mains switch I can sometimes hear the actuator motor spinning but not always and some clicks!
Hot water runs into the radiator pipes as long as the hot water taps are open!
Could it be the primary circuit pressure switch? Someone elsewhere on the site had a similar problem which was the heat sensor/thermistor, how do I test these before buying the part?
I hope this is enough info, I would appreciate some help please and thanks in advance!
 
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1 bar pressure isn’t high, it’s often just right, or under required from some boilers. Your hot water works, so unlikely the pressure.
 
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post pics of your thermostat and any other controls you have a the control panel on the boiler
 
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Thanks for the replies here are some pics

20220729_215307.jpg



20220715_212040.jpg


20220715_183409.jpg
 
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Have you set timer to constantly on?
Yes, was working fine like this for years and then suddenly after being off for a few hours the CH stopped! Are you saying it simply reset itself?
 
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Yes, was working fine like this for years and then suddenly after being off for a few hours the CH stopped! Are you saying it simply reset itself?
That is why I asked you to post a pic of the control panel, your on board timer is not calling for heat, you need to set it to constantly on, a pic is better than a thousand words, those timers are absolute cheap rubbish ,press the little M button (manual till it says H ON then you can control it with the thermostat
 
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That is why I asked you to post a pic of the control panel, your on board timer is not calling for heat, you need to set it to constantly on, a pic is better than a thousand words, those timers are absolute cheap rubbish ,press the little M button (manual till it says H ON then you can control it with the thermostat
@ianmcd Thanks, silly me, sorted! Up and running. Sorry for the trouble guys. Embarrassing! When you don't know, you don't know!
Well I learned other things on the way, that's good lol.
 
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@ianmcd Thanks, silly me, sorted! Up and running. Sorry for the trouble guys. Embarrassing! When you don't know, you don't know!
Well I learned other things on the way, that's good lol.
Dont be silly that is what this site is all about, I know quite a few pros that have been caught out with those horrible little timers
 

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