Combi boiler wiring advice please

[Marvo]

Duplicate threads merged.

 

[Lucien Nunes]

I suppose the grey and brown of each valve could be connected together if you can't connect the greys to the heating unswitched supply.

Nope, that would tie the two stats together when both valves are open, backfeeding via the boiler SL and preventing one valve closing while the other stat is still calling for heat. Greys must be fed with permanent live.

 

[yellowvanman]

Nope, that would tie the two stats together when both valves are open, backfeeding via the boiler SL and preventing one valve closing while the other stat is still calling for heat. Greys must be fed with permanent live.

My thinking was connect the brown of zone 1 (say) heating valve to the grey of zone 1 heating valve and the brown of zone 2 heating valve to the grey of zone 2 heating valve. Can't see how this would backfeed. In this case the greys are only live when the stats are calling as opposed to being permanently live.

 

[BoredSparky]

Why not just wire it properly in the first place? Bring all the wiring together into a wiring centre, you need a permanent live for the boiler anyway so just as easy to do it right!

 

[Gavsparky]

All wired correctly to a control centre as it should be

 

[Lucien Nunes]

In this case the greys are only live when the stats are calling as opposed to being permanently live.

Not true, greys can be made live from SL backwards through valve microswitch. See pic, shown with both valves open. When stat 2 or its programmer contact removes the supply from valve 2's motor, the motor would remain energised via the path shown dotted until stat 1 is also satisfied. Then both valves would close at once. And vice versa of course.