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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Electrical Questions >> Wiring for central heating -split location https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1519399190 Message started by londonman on Feb 23^rd, 2018, 3:19pm

Title: Wiring for central heating -split location
Post by londonman on Feb 23^rd, 2018, 3:19pm

The central heating pump has now been located down to the garage but the motorised valves (whose contacts will energise the pump when required) are located indoors upstairs. The garage is on its own circuit and the upstairs obviously has its own ring (all 17th edition).

So I'm wondering...the room thermostat will control the zone valve for the central heating...powered from the upstairs ring main. But the contacts on the motorised valve will have power fed from the garage (because the pump is there). Is this OK ?

If I do it the other way and, say, power the motorised valve and room thermostat from the garage supply then this means mains in the landing area that is not on the upstairs ring. Catch 22 ?

Or am I worrying unnecessarily ?

Title: Re: Wiring for central heating -split location
Post by thescruff on Feb 23^rd, 2018, 10:35pm

Not going to answer the sparky question other than to say, the Boiler, Mv, Pump and room stat all have to be linked somewhere.

Assuming we are talking about the same system, I don't like the way this is going without more information. Is someone clutching at straws?

Title: Re: Wiring for central heating -split location
Post by Lectrician on Feb 24^th, 2018, 6:55am

You need to run the pump from the same control supply as the valves. Where the valves are, is there no perm 230v?

Title: Re: Wiring for central heating -split location
Post by londonman on Feb 24^th, 2018, 8:25am

thescruff wrote on Feb 23^rd, 2018, 10:35pm:

Not going to answer the sparky question other than to say, the Boiler, Mv, Pump and room stat all have to be linked somewhere.

No, they don't in a situation like mine where there are two separate water systems and no, they're not clutching at straws.

Having converted to an unvented system everything is spot on. Just wish I'd bit the bullet earlier. Would have saved a lot of heartache and money and less hassle and a better system.

Title: Re: Wiring for central heating -split location
Post by londonman on Feb 24^th, 2018, 8:28am

Lectrician wrote on Feb 24^th, 2018, 6:55am:

You need to run the pump from the same control supply as the valves. Where the valves are, is there no perm 230v?

Funnily enough, I'd come to the same conclusion. Yes, one can easily put in a perm 255v supply. Yup, 255v is my incoming voltage...provided the hob's not on. "Long extension cable" if you recall !

Title: Re: Wiring for central heating -split location
Post by The_Trician on Mar 1^st, 2018, 5:35pm

So long as a single mcb isolates all, then you should be fine.