Baxi 105e completely dead

[Wolfy67]

I have a problem which I am hoping someone here can help me diagnose. The boiler was working fine for bot CH and HW last night, this morning nothing. There seems as if there is no power getting to the boiler as none of the led lights are lit, including the power on one. There is power from the spur as I have checked this, and changed the fuse there. The boiler itself is just dead. Hoping its nothing to serious but would be graeful for any advice as to solutions.

 

[Gasguru]

Remove two screws from lower panel, lower panel down - check fuse/power at wiring block after removing access cover on left hand side.

 

[Rob]

when you say fuse i assume you mean the 3amp in the spur.

the boiler is also protected by a 2amp glass fuse mounted in the terminal block where the mains supply enters the boiler.
this will probably have blown.

be aware if a fault has occurred on the PCB

 

[Wolfy67]

Thanks for the answers and help. I tried changing the glass 2 amp fuse and the power light did then come on. Unfortuntely as soon as the hot water was turned on the fuse blew straight away. I am guessing that there must be a fault on the PCB itself, but any more advice appreciated.

Edit

Having just taken the board completely off there is a black streak down the reverse side so guessing this is the problem.

 

[Baxmax]

Before you commit to a new p.c.b check the resistance values at the pump and fan,about 180ohms and 50 ohms,as somethhing must of sent your board west in the first place

 

[Vic Spanner]

Unfortuntely as soon as the hot water was turned on the fuse blew straight away. I am guessing that there must be a fault on the PCB itself, but any more advice appreciated.

Edit

Having just taken the board completely off there is a black streak down the reverse side so guessing this is the problem.

Microswitch going short circuit. Not uncommon for these to go..As Baxmax says check with multimeter ..

 

[Wolfy67]

Thanks for all the help guys. Have replaced the PCB but run into a new issue. The thermostats seem to no longer control the temprature of the water for either the CH or HW, its either scalding or warm. I remember reading somewhere that there can be a problem if the two thermostats arn't turned to zero before the board is replaced. The CH one seems to meet resistance about quarter of the way round before moving through. Anyone heard of this before and oknow of a fix?

 

[Baxmax]

Before you removed your existing p.c.b you should have set the c.h and d.h.w controls to zero to achieve the correct orientation when fitting the new p.c.b.A bit like locking the door after the horse has bolted.

 

[Wolfy67]

But any way to fix now short of taking off the board and putting it back on again?

 

[Baxmax]

No you must remove the board and zero the controls and refit the board,there will be trial and error unless you dont get it right first time..You will know it is correct when there is no resistance at any point between min and max and of coarse your temps will be correct

 

[Wolfy67]

Job done. All sorted now, all controls work as they should and we now have hot water and heat. Thanks again all.