baxi 105e

[oldplumber]

I attended a 105e combi a while back, fan starts and fails to run going to lock out so replaced aps, all went swimmingly and left. 2 weeks later same problem, aps funtioning now (wasnt before, I checked switching etc) so saw the flue venturi was a bit dirty outside it and popped a spare in and changed the silicone tubes. All running ok, but Im thinking the pcb may be at fault giving an intermittent problem, anyone else come across this before, a first for me as if the pcb goes its normally a complete failure straight way. cheers

 

[wards]

had weak fans in the past causing same fault.HTH

 

[Billy Bob Bob]

take the pcb out if its started to burn theres your problem also as said weak fans on early ones but a rare fault now also check the heat exchanger o rings are not leaking the water runs down the loom into the pcb causeing all sorts of weird faults

 

[wards]

as gas man said,a quick look at the board costs nothing.

 

[oldplumber]

cheers guys, had thought about fan but it was running up ok with no squeals or groans, I was trying to avoid the pcb question as the custard has seen to much of me recently, this particular boilers a nightmare, leaking seals etc, but he refuses to replace it at present, even though its cost him over £350 in callouts and parts in three months. still a nice little earner, apart from copping a parking ticket this morning while offloading kit, had to put most of it on his bill!!!, its getting so everytime you stop round here some long haired git with an electronic pad leaps out and slaps a sticky envelope on the screen ,2 in 2 weeks to date.

Anyhow sick joke "whats got 4 legs, goes woof and wakes the neighbours," Answer "some blighters cooker in Salford"

 

[REDSAW]

i attended one of them before, last winter.

same fault, changed the fan then it took out the pcb 5 mins later.
initially it is proberbly the pcb on its way (check for browning in the corner) but cost more than the fan which was dying anyway, trying to save the old dear some ££ ended up wwith a bill of £350.

 

[grahamgas]

I have had this problem on a few 105's.

Usual suspect as already stated, was the PCB.

Graham

 

[Reg Man]

I had similar probolem with a Sabre boiler. I diagnosed the lazy fan with a combustion test. I had changed the pressure switch. and this did not work. I bypassed this, and the combustion was bad. I therfore diagnosed there was not enough air flow and pressure to activate the pressure switch. New fan fitted works OK.

 

[SafeGasInstall]

hi ,could any one explain to me how can you prove a fun to be "weak fan" or "lazy fan"
i know on w bosch there is test point to reed neg pressure !
how about other type boilers???

 

[oldplumber]

In this case pcb change cured fault, wasnt fan, but if fan failing a new aps wont normally cure the fault so fan is next suspect.