Worcester 30 CDI conventional wiring

[Woodwould]

Evening all,

I am just after a little help with my Worc 30 CDI conventional boiler. I am wanting to wire in a two port valve, cylinder stat to open the zone valve and start the boiler and a volt free 'boiler enable' contact on my UFH control panel. Am I correct in assuming that if you connect Lr and Ls on ST10 this starts the boiler?

Cheers

 

[davebgas]

ST10 is the room thermostat and/or external timer terminal

Connect room stat live supply to Ls
Room stat Live return to Lr
Room stat neutra to Ns

 

[Woodwould]

Morning,

Yeah, I gathered that from the rather vague WB instructions, but for the room heating controls I only have a volt free contact to wire back to the boiler and as Lr and Ls come bridged when you buy the boiler I was presuming that I wire back the volt free to here so the boiler will switch on and off?

Cheers

 

[doitall]

Yes you remove the bridge, then one is the supply live, and the other the switch live.

 

[Woodwould]

Awesome, cheers doitall

This will give 240v across the volt free contacts then? It was just going to be an expensive mistake to make if it was wrong.

It was wired in to a Honeywell wiring centre with the zone valve and the cylinder stat. But it did not seem to work correctly, the zone valve opened on the cylinder and the UFH called for heat but the boiler was not kicking in. But when the temp on the boiler dropped to the setting on the built in dial, (whatever you set it at, between 40’c and 80’c) the boiler would come on.

Obviously this did not really affect the UFH because of the low temp it runs at. But for generating hot water through the coil in the cylinder it was not reliable, so I have disconnected it and currently the boiler is running permanently on its built in stat that is set on the dial (between 40’c and 80’c).

If it is functioning this way I am guessing is not the way it should be wired?

 

[doitall]

I would be very carefull what you are trying to achieve, and certainly wouldn't recommend playing with it.

We need a lot more information on what is fitted and how it is meant to be controlled.

 

[Woodwould]

Yes, I understand that’s why I put it to a simple system as I was not happy with what had been done. i.e. not working correctly. If it’s a simple system it suits simple people like me!

I have experience of domestic and light commercial wiring but have not ventured in to heating controls. The boiler installation was a mass of wires in to a Honeywell wiring centre, not very neatly done, it resembled a tin of spaghetti! So I thought if a jobs worth doing………

Its just a case of a bit of head scratching but I like to have everything done NOW, especially if it’s my own house!

 

[doitall]

Boiler wiring is outside the skills of most sparkies, unless they specialise.

As I said I couldn't possible comment without knowing exactly what is fitted and why.

 

[doitall]

Diynot on a go slow.

 

[doitall]

Diynot stopped working

With a bit of luck the mods will remove the last two posts when they wake up.

 

[Woodwould]

Yeah, yeah, next you will be telling us there is a differeince between plumbers and heating engineers!!!

 

[doitall]

Yeah, yeah, next you will be telling us there is a difference between plumbers and heating engineers!!!

Two different skills completely.

 

[Woodwould]

I have a Heatmiser UH1 – with the volt free contacts, this also controls all the room temps, a Danfoss HP22 zone valve (four wire) and an adjustable cylinder stat of far eastern origin.

Sounds simple when I put it like this!