Baxi Solo 3 40 PF Pump Stays On constantly - PCB or wiring?

[TheCorm]

My money is on a stuck microswitch in the 3 port valve.I'll bet it's been wired so that the pump L from the boiler activates the 3 port valve, and the microswitch in the valve then turns the pump on.

As you manually move the override lever on the 3 port valve (with power turned off) listen VERY carefully. Can you hear a little click inside the actuator body? If not then almost certainly the microswitch has failed. They can be replaced but it's a very fiddly job so buying a new actuator body might be the best solution.

I don't know that particular boiler, but I've found combination boilers that use a 3 port valve inside the boiler, and the same thing, a stuck microswitch leaves the pump running all the time.

Thanks ProDave, i'll give that a listen tomorrow.

Jamie

 

[TheCorm]

Sorry my reply is so late, been manic.

I've located a switch for the boiler which has made things a lot easier!

When switched off the pump goes off as expected.

The valve....I push it into from auto to manual I couldn't tell whether there was a click from inside or from the lever touching the side but when I let go it then slowly moves back to auto with a kind of water/quiet woosh from inside)

Corm