Boiler diagnosis - CH on standby, pump running but no flame!

[pls1]

I've got a problem with a Ferroli Tempra 30 system boiler - approx 6 yrs old.
The programmer and room stat are both calling for CH/HW but the boiler will ignite briefly (5-10secs max) and then go into standby mode (flashing green LED). Once in standby the pump will remain on but the fan will stop.

I've checked the zone valves for CH/HW and they are operating correctly, room stat/cylinder stat/programmer is calling for heat but boiler doesn't want to give it. Checked pressure ok - 1bar.

If I reset the boiler from the front panel it will go straight into standby with pump on (no fan/flame). Occasionally if I leave it for a few minutes turned off and then reset it will power up/ignite but then flame out/fan off after 5-10 secs.

This happened once or twice about a year ago but went away without having to work on the boiler.

Anyone any ideas?

 

[bellairaphon]

more than likely be the fenturi in the fan. ull know if u take the combustion case off more than likely fire up. or pressure switch but i think venturi breaking the combustion so need a corgi engineer

 

[pls1]

It fired up briefly with the combustion case off but went back into standby again within 5-10secs.
In the meantime I contacted Ferroli technical support who thought it might be the temperature sensors on the IN/OUT flow pipes.
Would appreciate a second opinion if that is a likely cause.

 

[bellairaphon]

the ferrolli temp n overheat stats have always been dodgey especially on the modena's worth a try

 

[numpty1]

most likely the thermistor,these boilers are renowned for weird faults,cheapest is the thermistor about a tenner once you have that replaced have the boiler serviced by a competent person who is familiar with these and knows how to diagnose faults,it may be a good idea to replace the venturi at the same time as the service,make sure he checks the exp vessel as these tend to be undersized on this model.