strange boiler question - gas valve, pcb and programmer

[jackecole]

weird question probably, but wondered if any breakdown engineers knew of this one?

apparantly a gas valve blew a pcb and programmer .... just wondered how this would happen.

DOnt know the boiler, just in general wondered/was thinking how this could do that! - unless a burnt out/shorted vale coil or bad connections at the gas valve caused the back surge??

 

[ChrisR]

GV blowing a pcb is common by drawing too much current.
Blowing a programmer is improbable.

 

[jackecole]

I suppose, why would it draw too much current though? Just a design fault in them? Or if the coil shorts?

 

[Agile]

The most common fault on a gas valve is the coil going open circuit because the very thin wire breaks. That does not damage anything else.

But just sometimes the insulation fails, often after shorted turns cause an increase in the current and thus the heat disapation.

In that case sometimes they short to earth or just draw too much current and fault the PCB.

Sometimes the PCBs have a component which is designed to fail to prevent excessive current being taken.

Tony

 

[jackecole]

HYou guys are amazing, thanks for explaining that.

I suppose some PCB's use more fuses to blow instead of damaging the board itself.

Is there another component the PCB has to prevent excessive current being taken Tony??

 

[Axel]

Another common fault is within the engineers brain - they change the wrong part first so have to keep changing other parts until the system magically starts to work again....

 

[kevplumb]

no thats parts changers who don't understand how a boiler works

 

[Boilerman2]

Its called treating the symptoms instead of the Cause!!

 

[kevplumb]

ive known enough of the first generation turbomax gas valves take the board out