Could any one let me know if it is a requirement to have isolation on motorised valve?. And if so would all poles need to be broken inc the aux.

It's not usual - particularly if isolation of that valve caused "hydraulic" problems.

The isolation would be via the control panel or wiring centre - ie if domestic, you turn off the fused spur feeding the CH controls.

If, for some curious reason, you do need isolation, then yes, every live conductor would require isolation.

Regards

OMS

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Failure is always an option

Thanks oms.

I am talking about a domestic situation, the timeclock /controls are downstairs. There are a number of valves upstairs, with no isolation. The pumps do have local isolation. As there is a complex control system even an electrician in the future maybe unsure if maybe a froststat of overun stat may enegise the valve. Just wondered if there was a reg looking for local isolation.

In general the wiring regs permit remote isolation provided it can be secured in an open position (e.g. locked off) - 537.2.1.5.
- Andy.

OK - there is no regulation demanding isolation, just that if isolation is required it has to comply with BS 7671.

So, unless you feel there is risk of trapping, crushing etc if the valve moves without warning (unlikley in a domestic) then you don't need any local isolation.

Presumbly, turning off the fused spur to the wiring centre kills everything anyway - and any spark stupid enough to have the cover off a motorised valve with the power on well................

Regards

OMS

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Failure is always an option

Some designs suggest adding isolation switches at various points. Nu-heat do for example suggest local isolation at UFH manifolds etc. this is particularly true wher heat pumps or the like are used, so they can just replace or work on part of the system without having to shut down the heat pumps.

You also sometimes see valves wired through a 6pin inline plug and socket, although I haven't for a while now....

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Regard
Richard (Dick)

www.rllewellyn.co.uk

I think BG used to wire their valves with plugs and sockets so it was easy for the "plumbers" to change them over.

We've done lots of UFH systems over the last few years as our farms have built new cottages and I've not yet put local isolation in. Sort of worked on the principle that if you couldn't work out how to isolate it safely using the FCU marked heating controls then you probably aren't competent to have your fingers in the wiring anyway

Stu

Agreed stu. I only ever worried to any great length with systems that would be commissioned by others to get the mcs, and figured I'd best stick to their design.

I had a lad second fixing a system for me recently, and he was going to town with isolators everywhere, triple pole in places to isolate back fed switch wires and things, cost me a blooming sight more than I'd allowed in the quote!

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Regard
Richard (Dick)

www.rllewellyn.co.uk

The safest way in a domestic home, is to turn off the main FCU marked Central Heating, and remove the fuse - Some CH master FCU's (mine included) have a padlock off facility, whereby a small padlock can be passed through the empty fuse drawer to lock off the supply.