honeywell rf stat

[hammers4spanner]

This is one for the guys with sparks knowledge on here ,,basically trying to save few pounds by wiring in my own rf stats instead of being over charged by an electrician.
The diagram isn't to clear to my limited knowledge
the stat is a honeywell cm927
the terminal points read NNL ABC
first things do i take the live out of the boiler into the stat as the diagram makes me think i need a 5 amp fused spur.
secondly are the T1 and T2 on the drawing the frost stat in the boiler ??
Any guidance would be hugely fgratefull and save me some pennies

 

[diamondgas]

It depends on what boiler you have to be honest H4S ... some are 230v, some low voltage and some volt free.

Basicaly L and N are self explanatory ... A & B are your switches. If your boiler is 230v then you don't need to run the feed just the switched live return. However any of the other two means you have to run them suply from boiler to A, switched live back from B Does that make sense?

 

[hammers4spanner]

todays was an glow worm 24 kw ultracom thought save some pennies but eneded up confusing myself , so i am to presume take live feed from boiler to L and N on receiver ?? Then take a supply from T1 and T2 into the A and B ??The C on the drawing is showing i presume a switch .

 

[Johnieb]

I was in the exact same position last week. I thought i would save some pennies too. I managed to do it, just about. but i totally agree, the wiring diagram on these is a bit confusing and it did my head in for ages. I took a three core out of my fused spur into the receiver, i wired the neutral into N (obviously) and then wired my live wire into the first L on the left only. The earth i wired into a small chock block. then I took a five core out out the receiver, wiring my Live and neutral into the same live and Neutral from the spur (i.e on the left side of the receiver). The earth from the boiler i wired into the other side of the chock block, so there was a permanent earth from / to the boiler. Then the two switch wires, i wired from the boiler into A and B. It worked fine. You dont need to put anything into the second L terminal in the receiver. Although, this confused me for ages as i kept thinking that there needed to be a linbk there, but there doesn't. hope that helps.

 

[hammers4spanner]

Instead of just coming out of fused spur can i not just come out of boiler LIVE and neutral supply??

 

[diamondgas]

Instead of just coming out of fused spur can i not just come out of boiler LIVE and neutral supply??

Yep with 4 core as these boxes don't need an earth I believe?

 

[dontknowitall]

Not read above fully, but I think the live should be from the power source, not the boiler.

Try this thread:

http://www.ukplumbersforums.co.uk/central-heating-forum/26311-y-plan-wiring-help-please.html

 

[Johnieb]

I dont think so Hammers. I agree, i think / am pretty sure you need to feed your receiver from your spur. Never seen it done from the boiler mate!

 

[dancinplumba]

feed it from your boiler, use the cable grip an heat resist flex

 

[hammers4spanner]

lol from boiler or spur seems to be a conflict of opinions !!

 

[dontknowitall]

Generally, live from consumer unit to 5amp fused switch to wiring centre.

Live to programmer, then to pump, then to stats, then to zone valves then to boiler.

 

[M.Joshi]

If the boiler is fed from the spur, then you can run the L & N from the boiler. If the wiring centre is nearby, then take your L & N from there. If siting the receiver near the boiler and the boiler has separate L & N terminals for external thermostats etc., then use that.

Try placing the receiver where it won't be blocked too much by the metal casing of the boiler. Although saying that, others have said that the Honeywell wireless thermostats are quite resilient.

 

[hammers4spanner]

It says in the instructions to locate receiver no closer than 30 mm from boiler ,, just had a brain blockage when trying to wire it in today all i wanted to know was can i take live/neutral from boiler into receiver and then from boiler frost stat into A/B on the receiver seems to have caused a difference of opinion which aint helping lol

 

[M.Joshi]

The important thing is that you have one point of isolation for all system controls.

Take the L & N from the most convenient point nearest the boiler - so long as it is all isolated by the same fused spur as the system/boiler.

 

[dancinplumba]

It says in the instructions to locate receiver no closer than 30 mm from boiler ,, just had a brain blockage when trying to wire it in today all i wanted to know was can i take live/neutral from boiler into receiver and then from boiler frost stat into A/B on the receiver seems to have caused a difference of opinion which aint helping lol

yes