Zone Valve Isolation

[NozSpark]

Are you allowed to use a relay/contactor for isolation purposes?

Personally I'd stick with a rotary isolator,,, the valve must be somewhere relatively hidden so why not put it with it

 

[buzzlightyear2014]

I would be wary of installing a user-operated manual over-ride of a heating control without checking with Vaillant.

Can the user just turn down the thermostat?

Has all been checked with Vaillant. Its only for isolation and maintenance on the valve, no power through valve, circuit won't fire and boiler doesn't run

 

[steptoe]

Problem is that's a bit fail dangerous. You are relying on the relay energising to isolate the supply, unless I have misunderstood what you are intending?

Im thinking fail safe,

power failure valve is dead anyway,

the other way is ensuring the relay will fall back and has not arc'd,

tbh, as Noz says, either way is probably not permitted for isolation purposes.

 

[Lurch]

Im thinking fail safe,

power failure valve is dead anyway

Wouldn't work like that, powering up a relay to isolate a switched live is not fail safe. If the relay failed then you have no isolation. General powercut in the area is not allowable as a safe means of isolation!

 

[steptoe]

Wouldn't work like that, powering up a relay to isolate a switched live is not fail safe. If the relay failed then you have no isolation. General powercut in the area is not allowable as a safe means of isolation!

Im not talking general powercut,

if you energised the relay it would isolate the valve, if you then lost power to the boiler then the valve would remain isolated,

having the relay permanently energised relies on it not 'growing' in the same way that RCDs often grow if they are never tested.

as pointed out though, this is probably one of the reasons that contactors/relays, are NOT permitted as isolation.

 

[Lurch]

if you energised the relay it would isolate the valve

IF

as pointed out though, this is probably one of the reasons that contactors/relays, are NOT permitted as isolation.

Exactly.

 

[Steve3948]

4 Pole Reyroll Plug and Socket, just pull apart for isolation.