Central heating system tripping circuit breaker (ed.)

[stunning]

My central heating system which includes the Potterton Suprima is tripping the circuit breaker.
If I switch off the isolation switch ((boiler and control panel), reset the circuit breaker, then switch on the isolation switch again it trips the circuit breaker immediately.
Any suggestions?

 

[stunning]

Just touched the bottom of the mid protection actuator and there was a drop of water there. I'm wondering if this is the location of the earth leak.

 

[JohnD]

Water leaks onto electrical parts are a common cause.

 

[oldbutnotdead]

MCB or RCD or RCBO- which is tripping? Pic is probably easiest...
plus what else is on that circuit?

 

[stunning]

This is the leak on the mid way valve

 

[stunning]

This RCD is tripping, currently in the good position.
This morning Ive switched it on and it hasnt tripped.
Also has the water pump in the circuit.

 

[stunning]

Also just spotted that the spring attachment is broken off, what does that spring do?

 

[oldbutnotdead]

Ok. First thing- where's the water coming from?
Second, the spring is usually quite important, fixable with an M3 or so nut and bolt.

 

[JohnD]

This is the leak on the mid way valve

Which way is "up" in your pic?

Water seldom drips upwards.

 

[stunning]

I unclipped the mid way valve and you can see the water leak. All pics are posted the right way up so far.

 

[oldbutnotdead]

Mmm that does look a bit crusty. And probably not repairable without removal (possibly not repairable full stop). Time to source a replacement.

 

[JohnD]

I unclipped the mid way valve and you can see the water leak. All pics are posted the right way up so far.

Could it be dripping onto some other electrical part, such as the pump or thermostat? Or a wiring connection?

 

[Harry Bloomfield]

Also just spotted that the spring attachment is broken off, what does that spring do?

The motor drives the valve to the intended position, and holds it there. Default position is water heating, powered can be either HW + CH, or CH only. The motor can only drive in one direction. The spring returns it back to the default position of water heating.

 

[CBW]

I would obtain a new 3 port valve altogether, I’ve had a valve leaking once on a 3 port valve, which was tripping electrics too.