glowworm flexi hx18 problem?

[mkflow]

hi,
customer of mine has above boiler on an open vented system. installed 2009. first f1 & f5 flasing on boiler carried out checks and only thing i could find faulty was 3port valve in airing cupboard not switch over to heating. customer did say before fault appeaded on boiler that had no heating. replaced valve run boiler tested, checked r/stat & c/stat and all switching over. run boiler for about two hours and now f4 is flasing???? anyone got any ideas?

many thanks in advance

 

[tamz]

Check pressures, flue for blockages, also electrical connections to gas valve

 

[mkflow]

thanks have check all and still no luck

 

[buckley plumb]

i might be a bit rusty on the hxi but is the pump wired to the boiler to give pump over run seen to many not wired correctly and they overheat due to not being able to dispursde the heatexchanger heat.

ant

 

[tamz]

Thats true. Always check the obvious.