Replacing Old Controller On Sundial Y Plan System

[craignigel]

Hello

I am trying to find out about the wiring for Sundial y-plan and its compatibility with different programmers.

The CH/HW system that I have is a fully pumped system with mid-position diverter valve, Sundial Y-plan. The present old controller is an old ACL Lifestyle (LS722) controller in the kitchen, which was one of the first to enable different time programming on different days of the week but with no temperature control except via a hall thermostat. The single base plate has the following connections:

N

L

1 HW OFF

2 NOT Connected

3 HW ON

4 CH ON

E

The thermostat in in the hall and is 2 wired.

As I am interested in purchasing a new controller. I have been looking at the British Gas Hive system or something like a Honeywell CMT927 but the latter will not control my HW. I like this model because it gives me 6 CH events (temp control) per day for each of 7 days. As I rent out rooms, this is important. Will the Hive system fit to the existing base plate connections shown above?

Please note there is no connection on terminal 2. Can you tell me why it is not used on Y-plan? Is this necessary for Hive?

I need the temperature to be taken from the entrance hall, where the present old thermostat is situated. The controller could go in the hall with a receiver wired to the kitchen base plate.

Thanks

Nigel

 

[Andy™]

no idea what backplate is used on either, but usually easy enough to change providing the new controller has the same outputs. CH off is not normally used

 

[Doc Hudson]

Welcome to the forum, I have never installed or seen one but the installation guide implies the wiring should be compatible. https://www.hivehome.com/guides/Hive_Installation_guide.pdf Other useful reading. http://recombu.com/digital/news/smart-energy-showdown-nest-vs-hive-vs-insteon-vs-honeywell-evohome_M12711.html On a Y plan, hot water off is needed to correctly position a three port valve in sympathy with the water and heating on signals to fire the boiler. Central Heating off is not needed.

Doc H.

 

[steptoe]

seems you want to change a programmer and seperate stat for a programmable stat,

so, no, your wiring at any one position is NOT compatible.

 

[NozSpark]

You could have a 2nchannel programmer and a programmable roomstat though.... just put the heating on continuous and alter the set points via the roomstat

 

[craignigel]

Thanks for the replies guys, much appreciated.

What I was hoping to do was to replace the present programmer with say the Hive receiver which connects to the boiler via the wiring centre using either the existing base plate or changing it if necessary. That's why I needed to know if the unconnected terminal 2 would be needed with Hive. Then I planned to remove the present thermostat in the Hallway....(do I link the 2 wires?) The new wireless Hive programmer would sit in the hall and communicate via my router to the Hive Receiver in the kitchen, passing on operating times for both HW &/or CH together with the temperatures that I set. It would then "inform" the Receiver when the set temperature was satisfied. The thermostat on the HW cylinder would work in the same way as at present, wired directly to the receiver.

Thanks

 

[ProDave]

All sounds too complicated for me.  I would leave it as it is.

Just what benefit do you hope to achieve?

 

[craignigel]

I need to replace the controller as the display is going (lines across). It must be 25 to years old!! If I get a circuit breaker trip I lose all the stored settings because the fitted rechargeable battery has long corroded and has gone. In any case I can only set one temperature for the CH when ON. I need a bit more versatility and at least a coupled of different temp setting during day and also night to cope with my room rentals.

So I'm taking the opportunity to find out about upgrading it. It's a challenge too and I'm interested in that kind of project!!

Thanks for taking time to post replies.

 

[ProDave]

I would just get a new programmer to fix the problems with the old one. Virtually any programmer will do what you want.

Then replace the ordinary room stat with a programmable room stat to give you the different temperatures at different times of day.

 

[Evans Electric]

As PD said .....  ask at a Plumbcentre or similar  ,  a modern controller should do what you want .  Most are fitted to a Standard British Gas  backplate including the existing one  and the supplier / paperwork should advise on any links that may need fitting .

No idea what this Hive thing is TBH .  As a DIYer  I would be very careful or you could foul up the whole system .  

 

[Richard-the-Ninth]

No idea what this Hive thing is TBH . 

Its a way of controlling your central heating via an app on your smart phone. The hive kit costs £199 including installation.

 

[Evans Electric]

Mon Dieu  !!

 

[steptoe]

you are NOT going to be able to change your room stat for a programmable one with the existing wiring,

end of,

you will have to add extra wires no matter what you do if you want to be able to change temps at different times of the day,

even with a HIVE system.

you will get it to work, just not properly.

 

[SPECIAL LOCATION]

As the man from Twatt alluded to....

Unless you actually modify the pipework to have more zones and thus more control over heating....

IMHO You are not going to get much extra from hive other than tapping in via wi-fi... 

There are cheaper programmable room stats that can give you different temperatures at different times..

Guinness