how can you tell when the pcb board on a COMBI is broke?

[JohnD]

No, it has to have an input of 240 volts.

Good grief

 

[charliechaplinspants]

No, it has to have an input of 240 volts.

Good grief

Congratulations, you win Householder ``don`t pull me up on my advice`` I`m not a pro, so that lets me out of being held accountable award! Enjoy.

 

[JohnD]

I was thinking of other inputs such as "call for heat"

Mine also has a primary flow switch, gas pressure sensor, temperature sensors on incoming and outgoing water; fan pressure switch, boiler temperature setting, cylinder stat, room stat weather sensor etc

And it has outputs to start fan, start pump (and overrun it); open gas valve; start ignition and time if it works; change condition of 3-port valve

What award do you get?

 

[charliechaplinspants]

Won`t get that far if pcb is knackered, smart boy.

 

[JohnD]

and if one of those devices is faulty, or a connector is loose, what do you do? Fit a new PCB?

 

[charliechaplinspants]

and if one of those devices is faulty, or a connector is loose, what do you do? Fit a new PCB?

Read what OP has asked.

 

[JohnD]

I have done

I also read what you said

...

a PCB is not an item I change often (as a heating engineer carrying out boiler repairs and servicing). Just because there is no output, does not mean the PCB is duff. It has to act on number of inputs to give an output.

No, it has to have an input of 240 volts.

Proper way to establish if PCB is faulty is to get to know what it is designed to do and then check the conditions that might be causing it to hang up. only then change it if it indeed is faulty.

Normally it runs the boiler and if there is no voltage from it, the boiler won`t work.

which I think is awful

 

[charliechaplinspants]

Normally, there is voltage into pcb and out of pcb, sorry, that`s the rule. all posts above were not made by me, you do realise that don`t you.

 

[Corgigrouch]

I would definately say that if a PCB was a black and charred mess, then it is pretty kippered... But since I have never seen one in such a state, I would have to test the boiler in a logical sequence

 

[gavinda]

might you even use..... [/gasp] a multimeter :shock

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