Central Heating and water not coming on? Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[oneahead]

Pilot on, new pump fitted recently. Suspect it is motorised valve? I manually moved valve yesterday to heating and it came on no problem. Today it will not even come on manually. Could it be anything else - i have a dis-continued old switchmaster valve which i believe needs pipe work/wiring when replaced - is this correct?

[rosebery]

Sounds like the actuator has finally given up the ghost and yes these things have been obsolete for ages.

All new 3 port valves have 4 or 5 wires, compared to the switchmaster's 6. Most 5 wire valves will fit on existing pipes, with only minor adjustments (you'll probably need to reduce each by a short amount). You'll need to remove the nuts and olives of course.

Wiring changes

SwitchMaster(Blue{Neutral}) - New Valve(Blue)
SwitchMaster(Green/Yellow{Earth}) - New Valve(Green/Yellow)
SwitchMaster(Red{S/Live}) - Link to Orange
SwitchMaster(Orange{HW On}) - New Valve(Orange)
SwitchMaster(White{HW Off}) - New Valve(Grey)
SwitchMaster(Yellow{CH On}) - New Valve(White)

Cheers

[oneahead]

Many thanks rosebery - any idea about the cost implication for labour and parts as i will not be able to do this myself?

[rosebery]

£ 80 - £ 100 plus valve. But get yourself a quote. There is no reason you shouldn't be able to do this yourself actually. Be happy that you can cope with any piping changes though and turn off the electric when doing it.

Cheers