Please help me understand the central heating...

Purple-flower

this is the piece that fell off the actuator

Alex1983

The third picture is the hot water actuator. This will most likely be the fault, it will be passing mains power to the orange to create a demand when there should not be one.

Some of the early Drayton actuators you were unable to remove from the body, the brass bit under neath. If you can remove the actuator head then it will be a straight forward repair, on the opposite side to the a and b sticker, if there is a black plastic button you can press in then you will be able to remove the actuator from the body by lifting up. If there isn’t then you will need to have the system drained down and the body and head both replaced.

You will not stop the boiler firing with out in wiring the actuator.

Purple-flower

Alex1983 wrote: »

The third picture is the hot water actuator. This will most likely be the fault, it will be passing mains power to the orange to create a demand when there should not be one.

Some of the early Drayton actuators you were unable to remove from the body, the brass bit under neath. If you can remove the actuator head then it will be a straight forward repair, on the opposite side to the a and b sticker, if there is a black plastic button you can press in then you will be able to remove the actuator from the body by lifting up. If there isn’t then you will need to have the system drained down and the body and head both replaced.

You will not stop the boiler firing with out in wiring the actuator.

Thank you Alex1983, I will try this tomorrow so I can go down to wickes to purchase any supplies needed

Alex1983

You’ll probably be better off getting it from screwfix, I don’t know if you get a direct replacement from wickes/ b&q etc. Strangely, if I’m reading it correctly it’s cheaper to buy the body and head together instead of buying just the actuator.

Purple-flower

Alex1983 wrote: »

You’ll probably be better off getting it from screwfix, I don’t know if you get a direct replacement from wickes/ b&q etc. Strangely, if I’m reading it correctly it’s cheaper to buy the body and head together instead of buying just the actuator.

I'll try screwfix to get a like for like repair, in the meantime is there any way to cut power to just this section and turn it on on demand? The plumbers I have spoken to say they have at least a two week backlog :eek:!! I really don't want the heating and hot water on constantly for two weeks before its repaired... I am a pretty competent DIYer but I'm always cautious when it comes to electrics

Rodders53

Probably a sticking microswitch inside the HW actuator making the pump run/boiler fire despite valve being closed by the return spring.... May be possible to free the switch off if the blue cover is removed? .... May then work properly for a bit or more likely stick again next time HW is called for. (Rarely the contacts weld closed so won't free off).

Heating system Mains off first for safety, of course.

I've even replaced the microswitch in one similar actuator rather than buy a new head; but then my time is free and I can solder, and understand electrics as well as plumbing, and I found a source for the correct microswitch online.

The BGMVSP-2 ones were British Gas, I believe. I think Drayton do an equivalent valve and head (in Wickes/Screwfix) that should just fit on the existing valve.
Wire colours will almost certainly be identical between the two heads, so fairly easy to swap over for a competent d-i-y person, with due caution exercised.

http://www.draytoncontrols.co.uk/sites/default/files/Motorised%20Valve%20Installer%20Guide.pdf

Purple-flower

Rodders53 wrote: »

Probably a sticking microswitch inside the HW actuator making the pump run/boiler fire despite valve being closed by the return spring.... May be possible to free the switch off if the blue cover is removed? .... May then work properly for a bit or more likely stick again next time HW is called for. (Rarely the contacts weld closed so won't free off).

Heating system Mains off first for safety, of course.

I've even replaced the microswitch in one similar actuator rather than buy a new head; but then my time is free and I can solder, and understand electrics as well as plumbing, and I found a source for the correct microswitch online.

The BGMVSP-2 ones were British Gas, I believe. I think Drayton do an equivalent valve and head (in Wickes/Screwfix) that should just fit on the existing valve.
Wire colours will almost certainly be identical between the two heads, so fairly easy to swap over for a competent d-i-y person, with due caution exercised.

http://www.draytoncontrols.co.uk/sites/default/files/Motorised%20Valve%20Installer%20Guide.pdf

Thank you Rodders53, I am going to tackle this task on Monday just in case I need the whole day to hose out radiators or balance the system while I am at it :cool: