Baxi 105e no heating

[Taza]

Please can you help.
Hot water works fine.
But when I switch heating on,the heating neon does not come on.
Check the signal from the heating control to the boiler that's ok.
I have a new central heating temp sensor so connected that up,still no heating neon light.
I have a new safety thermostat so connected that up,still no heating neon light.

Any ideas

Col

 

[Agile]

Changing a few parts without any reason?

What have you done to check the DHW flow switch?

Which exact model is it?

Tony

 

[gas112]

Bridge out the external controls on the boiler terminal strip to confirm boiler fault

 

[Taza]

The external supply is ok checked at the terminal block
Heating off no volts
Heating on I get 240v at terminal block.Link out still did not work.
No neon heating light ???????
No flashing warning lights ???????
Col

Model Baxi Combi 105e Instant
What have you done to check the DHW flow switch? ?????????

Cheers

 

[cemal]

taza diverter valve

 

[Ihavenojob]

Daft question,but is the selector switch in the heating&water position?

 

[Taza]

Lol
Yes it's in the heater & water position.
Diverter valve can you repair or should I just buy a new one.are they easy to change.

Cheers

Any more thoughts guys

 

[Taza]

What condition's have to be right before the heating neon lights up.

What switches have to be made.

If its a faulty switch why has no warning neons lit up.

Googled this problem and it comes up on several forums but the guys who put the post on don't seem to say at te end of the thread what the actual fault was.

Cheers

 

[gazthepottertonengineer]

If there is definately power to the switched live and the heating neon isn't lit and the selector switch is in hot water and heating position then it can only be either the selector switch or the pcb that is faulty!

 

[Taza]

Yer defo in the right position,
Strange thing happend today switch heating on checked the supply at the terminal block switch wire 240v.
No heating neon lit up.
After about hour the heating came on ??? Then went off after a while.
When it went off I checked switch wire still got 240v no heating neon.

Asked if anyone in the house had done anything and the lad said he had a bath.??

Just tried again still no heating but got signal to switch heating on.

Thanks for all the replies so far

 

[gazthepottertonengineer]

Does sound like pcb! Probably dry joint on it!

 

[Taza]

Cheers Gaz
Will check it out

 

[Taza]

This is doing my head in.
never got round to changing PCB as the heating would work after we switched the tap on for the hotwater,if we ran the hot water for ten minutes and then switched hot water tap off,the heating would kick in. ????

any ideas

Taza

 

[Taza]

Thanks Cemal
Problem sorted it was the Diverter Valve

 

[Agile]

What have you done to check the DHW flow switch?

Tony

If you had followed by advice 11 months ago you could have fixed it then!

The diverter valve operates the DHW flow switch and I would guess it was jamming in the DHW position.

Tony