Replaceing Thermostat Help!

[OptimalKiller]

Hi everyone,

I have an old thermostat a Drayton 533 & I want to replace it with a new digital one. so could someone point me in the right direction on how to fit the new unit.

On the mechanical thermostat I have 3 wires connect to the unit.

The blue wire connects to the connector labeled N, which i assume is neutral.

then I have a red wire which connects to the connector labeled L, which i assume is live.

Then i have a yellow cable which connects to the connector labeled Heating load.

on the Digital thermostat I have 3 connectors Application

Wiring Diagram for 230V

SL Off - Heat Off
L - Live
SL (ON) - Heat ON
N - Neatural

Wiring For Volt Free Application

NO - Switched Live (Volt Free)
COM - Volt Free Feed
NC - Normally Closed
N - Neutral
L - Live (230V Feed)



So which wire connects to which? Please help

Thanks in advance

Glyn

PS. I have a combi boiler if that has any relevance

 

[Gas2Air]

What combi do you have, some have 240vc into the board and some now have volt free contacts to connect to.

 

[OptimalKiller]

its a Baxi Potterton Main Combi 24HE Combi boiler.

I saw this in the manual.

IMPORTANT: The room thermostat MUST be suitable
for 230V switching.

does this help?

 

[Gas2Air]

Do you mean the Platinum HE24? If so the RS needs wiring to the boiler as you state with 240v switching, it would be easier to use an RF wireless stat and receiver that is linked to board?

 

[OptimalKiller]

Thats what I'm trying to use now an RF Thermostat, I took the old analoge thermostat off the wall and these are the only wires I have available. so can I use these wires to connect up the RF Thermostat if so which wire goes to which coonector.

What I was thinking of doing was to do the following

useing the guide for Wiring Diagram for 230V

L - Live Connect the Red Wire from the old thermostat
SL (ON) - Heat ON Connect the Yellow wire from the old thermostat
N - Neatural Connect the blue wire from the old thermostat

Thanks

Glyn

 

[Gas2Air]

Thats what I'm trying to use now an RF Thermostat, I took the old analoge thermostat off the wall and these are the only wires I have available. so can I use these wires to connect up the RF Thermostat if so which wire goes to which coonector.

What I was thinking of doing was to do the following

L - Live Connect the Red Wire from the old thermostat
SL (ON) - Heat ON Connect the Yellow wire from the old thermostat
N - Neatural Connect the blue wire from the old thermostat

Thanks

Glyn

You will not need any wires to the new RF, if you have any after you dismantle your old 240v one make them safe and bury them.

The RF will be battery operated. Has the boiler got an integral timer or seperate one ie on the wall? Normally with this boiler as most baxi it has a link on the mains terminal 240v block in for fitting of external controls.

 

[OptimalKiller]

Maybe I'm getting confused, On my Boiler I have a anagloge dial which I can set the time by pressing in the switches, which I dont want to use. However my thermostat analoge is already connected to the boiler to control the room tempature, now I have just brought a Wireless thermostat Horstmann HRFS1 Room Thermostat

http://www.screwfix.com/search.do;j...KCSTHZPCFFA?_dyncharset=UTF-8&fh_search=93829

so all I want to do is replace the old room thermostat with the new wireless room thermosat

Thanks

Glyn

 

[simond]

What a hideous looking product, looks like it was designed in the 70s. I imagine the budget wouldn't stretch to the superior Honeywell CM unit?

Wire it up as you suggested. On your programmer you will need to leave the CH on permanently if it is to work properly.

 

[D_Hailsham]

What I was thinking of doing was to do the following

L - Live Connect the Red Wire from the old thermostat
SL (ON) - Heat ON Connect the Yellow wire from the old thermostat
N - Neutral Connect the blue wire from the old thermostat

If you are happy with the wireless receiver in this location, then that's the way to wire it. But you need to follow the instructions to wire up for 230V.

You will not need any wires to the new RF, if you have any after you dismantle your old 240v one make them safe and bury them.

You may not need wires for the transmitter (battery operated); but you certainly need wires for the receiver.

The built-in clock on the boiler must be set to constant.

Are you aware that the Horstmann HRFS1 is an obsolete model? There is no info at all on the Horstmann web-site.

 

[OptimalKiller]

thanks for all your help, i have now resolved the problem. I had to bridge the wire from Heating load to Live on the RF receiver. All is working. However I'm going to change the unit as it looks horrible, can anyone recommend a good wireless room thermostat.

P.S. thanks to everyone help. much appreciated.

Thanks

Glyn

 

[D_Hailsham]

can anyone recommend a good wireless room thermostat.

Honeywell CM921 (24 hour) or CM927 (7-day) are probably the best around.