Hello

Installed DanfossRandall Y plan contractor pack.

The HW circuit works fine in all respects, but CH circuit doesn't.
Someone gave me this table:

ORANGE BROWN/WHITE GREY
OFF 0v 0v 240v

DHWonly 240 0 0

DHW + CH 240 240 reduced voltage

CHonly 240 240 240


I checked these off and they all came up fine, BUT
when I pulled off the actuator head to watch it cycling through the
positions it failed to return to the HW only position when I turned off
everything at the controller. Cutting power to the controller DID make
it return. Is this most likely to be an Actuator or Controller fault?

Also, when I manipulated the spindle of the 3 port valve manually it
made the pump sound as though it was having problems when set to the CH
only position, and it still failed to get the pipes warm...

Also (!) the Boiler fails to stay alight for longer than a few minutes
at a time, especially when set to CH only... under what conditions does
the boiler shut down other than over heat? It is a Glow Worm Space
saver 52. Would it shut down if it was pushing against flow restriction
in the rad circuit ?

Taking all this into account, I reckon I have 3 possible (maybe 4?)
problems.

1 flow restriction in the CH circuit
2 Faulty controller
3 Faulty Actuator
(4 sticky valve in 3 port body causing 1?)

Bearing in mind all voltages across actuator seem fine and it cycles
through all positions smoothly my opinion is that it is an actuator
problem causing it to fail to return to its default HW only position.
But it also seems I have a flow restriction causing the pump some
problems...

Please release me from this plumbing hell, its getting cold and I live
with 3 slightly concerned tenants! At least they can have a hot shower.




Cheers