How to replace a Baxi 105E microswitch?

[ShaunCorbs]

The front diaphragm doesn’t control the pump the rear one does

 

[paul_cragg]

The front diaphragm doesn’t control the pump the rear one

The front diaphragm doesn’t control the pump the rear one does

So do you think that may that one has also split? I have ordered so fingers crossed

 

[ShaunCorbs]

That’s the pump proving one so providing your info is correct should fix your problem or it’s a weak pump

 

[paul_cragg]

Sorry, I have one last quick question, when I replaced the DHW diaphragm, I just turned the Mains off and ran the hot tap until there was no more water. Am I able to do the same when replacing the CH diaphragm or do I have to drain the boiler?

 

[ShaunCorbs]

Have to drain the heating system if your upstairs and above the radiators only need to drain the boiler but if your downstairs need to drain everything above the boiler

 

[paul_cragg]

Have to drain the heating system if your upstairs and above the radiators only need to drain the boiler but if your downstairs need to drain everything above the boiler

Thanks for all your help, so just so I am clear if you are replacing the DHW diaphragm you just need to turn mains off and run tap but if you are changing the CH diaphragm you have to drain the boiler? I will also get some fernox inhibitor when I do drain it down

 

[ShaunCorbs]

Correct and anything above the boiler