Potterton promax he 24 / baxi

[newagegasman]

Ive had a fault with the above boiler and the baxi version about 6 months ago nothing made me suspect the boiler until today. what happens is it runs for maybe 2 hours and then goes dead it looks like theres no demand on the switch live when it does. so previous engineers have changed three port etc. i checked the condense trap flow and return, pump etc and even tanks in loft. it analyses perfect and is so intermittant. i cant get this one to simulate the fault the only difference between this one and the baxi is they have to manully reset it when it happens whereas the baxi has no lockout fault. neither does this sometimes. is there any common fault on these that i should be aware of??? so i know where to start??? cheers.

 

[zeebeedee]

Dodgy room stat/clock?

 

[newagegasman]

yeah see that what it looks like but its gotta be something with the boiler ive had the same fault twice with the same sort of boiler. i spent ages on one visit and put it back for an electrician.all power on the orange wire. but just goes dead no lock out nothing. today got me thinking its a common baxi fault.

 

[zeebeedee]

You mean the voltage drops off from the switch live? If so then its not the boiler it's on the external controls?

 

[mattyp]

Had this fault before- on one occasion it was the board also had faulty flow switches

 

[newagegasman]

which pcb???? no the power dosnt drop. theres power but its on but dosnt fire up and when i crack the multimeter out it fires up.. which pcb??? i wanted to be sure.

 

[mattyp]

You are testing me now ! Think it was the ignition, might be worth a call to makers ! If you have the time why not link out the flow switch to see if it locks out then ?

 

[newagegasman]

Yeah, i couldnt today was sat. problem is i was there for well over an hour and didnt go to lockout, it just look like theres no demand on the boiler with all controls on i did think flow switch pcb etc but there is two.the other baxi never went to lock out just spaights of firing up and going dead after a while it fires up again. cheers.

 

[Nostrum]

Flow switch would be my bet, I got caught up with the same problem for ages. Can be bridged out to test temporarily. Nightmare to change as well.