Worcester 28i junior combi - wiring up a prog room stat q's?

[ryangordon]

Hi all

I have a combi boiler - WORCESTER 28i junior

There's a switch next to the boiler (with a neon light when turned on) and this is left on in order to get hot water when a tap is opened.

I have just moved into the new house

The hot water is great - not too long to reach taps and v hot. But there is no heating (i tried to test it but there is no timer or room thermostat)!

I have the boiler manual and it says - for a programmable room stat installation, a NEUTRAL wire from the prog room stat should go to the NS terminal at the boiler , the Live wire to the prog room stat should go to the LS terminal at the boiler and the Switched Live wire to the prog room stat should go to the LR terminal at the boiler

Is this correct? What I mean to ask/clarify is: if I buy a prog room stat and it required no neutral wire (ie has a battery instead) to i just need 2 wires to the boiler/prog room stat??

Also, is the Live connection to the prog room stat from the boiler (also known as a COMMON terminal) and the switched live from the prog room stat to the boiler, also known as the CALL terminal - as when i wired in a standard room stat in my old house about 3 years ago, the common and call terminals were used (and i'm presuming its just different terminology for live and switched live??)


One last question - with a standard boiler, all the wiring, ie from the 3 port, room and cylinder stats, programmer, mains live in, switched live to pump and boiler are all wired up together via a wiring centre. With a combi boiler, and only wiring is required for the heating side, does the heating circuit get its power directly from the boiler, due to the boiler having a permanent live to it (which is also required for the h/w to work instantaneously)??

Thanks for reading, sorry if I sound v confusing!

 

[chassmith]

Hiya,

I can help on this one (I think)! - with a combi, you will need a wire from the combi terminal strip to the programmable room thermostat, as you say, you may not require the neutral. So just use a 2 core wire.

Yes the LIVE to the programmable rookm thermostat is also known as a COMMON terminal, and the SWITCHED LIVE terminal is also known as a CALL terminal.

A combination boiler needs to be turned on at the switch (permanent live supply) to supply hot water when required at the taps, etc .... also it provides power to the LIVE/COMMON terminal of the programmable room thermostat (in your case) through the permanent live that the boiler itself has.

tThus, if the switch is turned off, you will not only get NO hot water, but you wil also get NO heating!!!!

 

[bengasman]

The answer is really simple. Look in the boiler manual and the thermostat manual, all the info you need is in there.
If that doesn't make it clear, don't do the job yourself as you would risk damage to the boiler and yourself.

btw, the info about the ls supplying power to the roomstat is incorrect.

 

[ryangordon]

Hi again

I will no how to wire up the stat (just the terminology is not clear).

Basically it gives 3 examples in the boiler manual, 1 for a room stat, 1 for a programmer and the 3rd for a room stat and programmer. I am presuming the room stat (option 1) means a prog room stat??

 

[ryangordon]

The answer is really simple. Look in the boiler manual and the thermostat manual, all the info you need is in there.
If that doesn't make it clear, don't do the job yourself as you would risk damage to the boiler and yourself.

btw, the info about the ls supplying power to the roomstat is incorrect.

l/s to the prog room stat surely must be correct??
on second looking at the boiler manual, LR terminal from the boiler seems to be the supply to the prog room stat! .... although the terminology isnt very clear, as for a prog or prog and standard room stat the LS does supply power to the prog !! )different way round for a prog room stat)??

 

[mrgas]

Worcester Greenstar Junior.
If using programmable stat.
Ls Live to Stat
Lr Switched live from stat.
If the stat you use needs a neutral (many do not) take the neutral from Ns.

 

[steved101]

LS to sat (Live/common terminal) terminal and switched live (call) temrinal from stat to boiler's LR terminal. As mrgas said, if a neutral is needed from the stat. then use the NS terminal.


The combi gives the prog ropom stat it's permanent live (from the LS terminal to the stats live/coomon temrinal).