Worcester 240

[Boxer998]

Hello

I've cribbed off this site a thousand time but now I've hit a snag that I can't seem to solve so need to post.

Woke up yesterday morning and the rads were hot. The boiler (worcester 240) was running even though it is not on a timer and the switch was off.
I climbed up into the loft and had a look.

Could smell burnt electrics so switched off the power all stop.

switched back on and saw sparks coming from the righthand (three wires) switch activated by the diverter valve.

Stripped the valve off and the connections were fried.

Got a new (secind hand, both switches) assembly and fitted it.

Now the CH switches on and off on the switch, result.

However when you turn on the HW tap the diverter activates, the switches are switched and the boiler switches off!!!! Not so good.


Any clues?

What is the function of the two way switch? As that was the one that was cooked I'm guessing it tells the boiler to come on when the diverter valve switches it? what is it doing when the divert is closed?

What is the other switch doing? is it a flow sensor? if that was faulty would that switch the boiler off.

One of them switches the pump off I've worked that out. and that one works as you can hear it cut.

 

[matt1e]

However when you turn on the HW tap the diverter activates, the switches are switched and the boiler switches off!!!! Not so good.

Any clues?

are you sure you have wired the micro switches correctly?

switched back on and saw sparks coming from the righthand (three wires) switch activated by the diverter valve.

considering its normally the left hand switch that has the three connections,
are you sure you have wired the microswitches correctly?

What is the function of the two way switch? As that was the one that was cooked I'm guessing it tells the boiler to come on when the diverter valve switches it? what is it doing when the divert is closed?

it does the same when closed but takes the central heating controls out of circuit when hot water is demanded

What is the other switch doing? is it a flow sensor? if that was faulty would that switch the boiler off.

the other switch tells the pcb to run in DHW mode and use the HW sensor etc

One of them switches the pump off I've worked that out. and that one works as you can hear it cut.

you've worked it out wrong as it should not do that
so either
you have a faulty microswitch or the white cable core to them is open circuit
the pcb tracks are open circuit
the main rocker switch is open circuit on the hotwater connection(white)
or you have wired the switches incorrectly
it should be yellow top, white middle, grey bottom
a word of warning
do not experiment by swapping the connections on the micro switches around, the violet and red cores are extra low voltage and should be on their own switch, seperate from the grey yellow and white cores which are at mains voltage

 

[Boxer998]

Thanks for all that .

I've replaced the whole switch unit and PCB connector as a unit.

Just checked and the switches are working. all wires are identical to previous (fried) version

Noticed that with the switches off the diverter (not pressed by the valve pin) I can get hot water when the CH is on?

Is this OK (short term) or am I putting the whole system at risk?


I'm going to try it cold with no central heating on to see if it's anything to do with over temp or over pressure? But that will have to wait until the hot house flower is out for the evening.

 

[Boxer998]

Noticed that with the switches off the diverter. If I press the two wire, left hand (as you look at it fitted) switch (the one that switches to DHW running?) the gas cuts off.

Could this be to do with the whole thing running too hot? Only ask because with the switches off the diverter and the CH running I managed to run a bath and for the first time in history shes waiting for the bath to cool down!

 

[Boxer998]

Hello?

 

[Boxer998]

still no HW when the ch off and the boiler is cold.