Vokera Flowmatic 20/80 rs no hot water

[entreri911]

i have been having trouble with this for a while, i can only get hot water when the boiler is in CH mode. i have replaced the diaphragms in the CH manifold and DHW manifold but no luck. i have noticed that when in CH mode the spindle in the CH manifold moves and breaks the micro switch however when the hot water is turned on although the DHW spindle moves and makes a switch the CH spindle only moves slightly and does not break the switch. i was thinking that this may be the fault and if it is does anyone know how to fix it.

like i said i have changed the diaphragm in it so i know they are not the cause but now i am scratching my head, any help would be appreciated.

 

[nicknox]

Remove the switch from the pump ch/pump flow switch and push in and out with pliers (being careful not to scratch it). The spindles can get dirty and not move smoothly. You might also find the pump might be weak.

 

[Agile]

I think that you have said that the DHW pin only moves slightly.

It needs to move about 10-12mm to operate the microswitches. Try operating them by hand and see if that brings on the boiler.

Just changing the diaphragm is only half the story. You have to clean out all the moving parts in the manifold and grease them until they move easily and smoothly.

I know that you all imagine that fixing boilers is easy because plumbers can do it ( sometimes ) but the reality is that considerable skill and experience is required.

Tony Glazier