3 Wire stat and timer on Vaillants, best way to do it?

[Paul - PDS]

Hi all,

Fitting an Ecotec Pro at the moment and usually i just wire in a Honeywell programmable room stat. However, the customer would like to keep his trusty old 3 wire room stat already in situ - but he wants a timer at the boiler end too..

Could someone please tell me the best way to do this, with a Vaillant mechanical timeswitch perhaps? Forgive me for sounding a bit thick, just never use this setup!

thanks in advance,


Paul

 

[Ermintrude]

Use two contacts on stat which open and close on temp. - then wire a clock in series with stat. Use the 24v connection on pcb.

 

[Leo21]

Stick a150 plug in timer and wire stat like you do a programmable stat.

 

[kozak1968]

Take the red link wire out of the 24v side on the left of pcb and wire stat in and fit the 150 time clock.

 

[Nostrum]

Wire through 240v as you should supply a neutral for the room stat.

 

[AWheating]

Is it not in the boiler instructions?

 

[Leo21]

Is it not in the boiler instructions?

Yrs, but it's as clear as mud.

 

[Paul - PDS]

Thank-you chaps I'm gonna take your advice and use the VT150 and remove 240v link, it seem the instructions aren't the best when it comes to controls!

 

[Ermintrude]

Wire through 240v as you should supply a neutral for the room stat.

Controls and pcb last longer if u switching with 24v - as per valliant tech. Why does sat need N? And where you gonna pick nutral off the pcb? It's s/l?

 

[Leo21]

Controls and pcb last longer if u switching with 24v - as per valliant tech. Why does sat need N? And where you gonna pick nutral off the pcb? It's s/l?

240v stats are supposed to be wired with a neutral. Anticipator or something.

 

[Vee]

No 5 used to be the neutral on 240v, not in the instructions though. Best check with Vaillant.

 

[ambrosia]

Wire through 240v as you should supply a neutral for the room stat.

I know your meant to do it that way to make the room stat more efficient, however 24v through something which is likely to fall apart over the years just seems safer, room stat are hardly as sturdy as light switches