Baxi HE133 Boiler Fault Finding Help Please

[picasso]

You sure the diagram aligns with the one you posted ? if its got a molex connector it should be the next diagram down on the pdf.

 

[hodder_fisher]

Ahhaa, I looked at Fig 4 for the honeywell valves and agree with you logic on SPST so thought I had better double check the actuator fitted to the boiler and its different than the spare I acquired (which is Fig 3 and shows SPDT config), it is configured for SPST control (Pic below)

So excellent spot ! thanks

Now back to the fault, could it be the Actuator as it should have permanent 240v on pin 3 and 240v as well on pin 6 when CH demand is on. This is what I have measured on the boiler !

Thanks

 

[picasso]

So your looking at changing the actuator as the pcb is sending what its supposed to.

 

[AGAS]

going round in circles here

 

[hodder_fisher]

Yeah thanks, back to the 1st item i changed - good lesson learnt to check if the replacement part is the same as the one removed. Will pick up a new actuator tomorrow from the local gas merchant and try tomorrow night.

Yes AGAS going round in circles one could say, but at least I now now how the system works

Thank you for you support gents.

 

[DP]

Figure 3. the first one you posted , cant see how you can have 240 on both brown and black with a spdt relay.

When relay operates, cam eventually breaks the drive and other contact is made completing the circuit for drive home when relay releases. Am I missing something?

 

[picasso]

Relay on the boiler pcb not the relay in the actuator head.