biasi 28s keeps locking out

[bengasman]

Biasi 28s keeps locking out on heating, dhw appears to be fine.
Boiler stats for dhw and ch are both set about medium.
It has a new pcb and a new fan, thermistors measure correctly, flame sensor and leads are fine, aps seems fine, power supply is clean.
Boiler gets serviced every year and is clean as a whistle.
What did I miss apart from a few cards to complete the deck?

 

[sooey]

Slow pump?

 

[bengasman]

Slow pump?

forgot to mention, but pump seems fine.
spins freely, no muck and it happily deals with full load on dhw

 

[Agile]

I assume you mean an ignition lockout?

The minimum gas setting of the GV is at zero so it modulates down to no flame!!!

First thing you should have checked on arival !!

Common fault on the Baxi 80/105s too.

Should have been in the RGI only part!!!

Tony

 

[bengasman]

Did not think about the other side of the site, would have been better indeed.
Only changed the board a month ago and all was fine. If I remember correctly, it modulated down to about 2 mbar, but will check again. Only heard about the problem couple of days ago, and as they are opposite direction of where I am going at the moment, I thought it would not heart to check if there are any known issues, like this one.
Thanks Tony.

 

[Agile]

Check by pulling off mod coil contact.

There is no other common cause apart from too low min pressure on this model but then there is always scope for something very rare!

Tony