Help needed wiring up my new SUNVIC programmable room stat

[havetobelieve]

This is my first post and having read through many posts on here this morning, I still am yet to find one that can help me directly. This is a very good forum though and I have learned a lot from reading through various posts.

Anyway my post :-

I have bought a SUNVIC programmable room thermostat (£30) It is a TLX6501. I currently have a DRAYTON TEMPUS 7 programmer which controls both HEATING and HOT WATER. I have a 3 port valve and a circulating pump also, which are both upstairs in the airing cupboard, behind my bath.

Basically I know currently I do not have the CH ON terminal wired up in the programmer, as it is not required. But, for a programmable room thermostat to work, I will have to slightly alter the wiring to my system.

My old room thermostat is a normal type, and has 3 wires going to it. They are marked as COMMON, CALL and NEUTRAL.

The new programmable one has 3 terminals, COMMON, NO and NC.
From reading the instruction booklet it says connect live to the COM terminal. Connect HEATER/COOLER in series with NO and neutral. So, I am a little puzzled here. Is heater the ON (CALL) terminal and cooler the OFF (SATISFIED) terminal ?

I need a permanent live for the programmable stat to work properly, to come on independent of the programmer (and also will no longer be wired to the programmer)

Am I way off track here or nearly there...? Please help experienced plumbers/heating engineers.. I have done some plumbing and wiring myself in the past, I have replaced a faulty cylinder thermostat and a circulating pump, rad valves by plugging the feed tank feed and vent pipes, and installed new rads in my home, so am not a complete dunce!!!

Looking forward to your help. Hoping to get this done this afternoon

 

[mogget]

Usually the easiest way is to replace the old room stat with the new programmable one, and set the old heating timeswitch / programmer to continuously on. This hands over control to the new room stat.

As the new room stat is battery powered, it doesn't require a neutral. The neutral should be terminated safely and the existing live and switched live connected to common and 'on' (call) respectively.

 

[havetobelieve]

if the heating is constantly on won't it waste energy? i know techincally it won't but just having the programmer light on all the time kind of worries me !

thanks for your advice though, i'll think about it and probably do it this way.

what is the easiest way to exactly change the wiring though....

 

[mogget]

The new room stat itself will interrupt the supply to the heating so the only 'extras' will be the light and relay at the timeswitch, which will be very little even in comparison to the small amount used by the 3 port valve.

I've just looked up the diagram for the tempus 7 however, if you take the wire out of terminal 4 (CH ON) and connect it instead to the permanent live at the programmer, this should have the desired effect.

 

[havetobelieve]

Thanks for this advice.

Yeah as you say the only thing is the light on ht eprogrammer, but what do you mean by the relay?! Sorry, if it's a stupid question.

Thanks also for looking up the diagram. My programmer seems to have the live and neutral taken DIRECTLY from the spur right next to it and also an earth has been added - and the other 3 wires, CH ON, HW ON and HW OFF are the only ones run directly upstairs and to the wiring centre.

I'm still a bit unclear, it's that time of the week!!

 

[mogget]

Thanks for this advice.

Yeah as you say the only thing is the light on ht eprogrammer, but what do you mean by the relay?! Sorry, if it's a stupid question.

Thanks also for looking up the diagram. My programmer seems to have the live and neutral taken DIRECTLY from the spur right next to it and also an earth has been added - and the other 3 wires, CH ON, HW ON and HW OFF are the only ones run directly upstairs and to the wiring centre.

I'm still a bit unclear, it's that time of the week!!

A relay is an electrically operated switch - it's the bit that 'clicks' inside the timeswitch when it switches on or off. This is so that a low voltage signal can be used to switch a much larger voltage/current, for example a 5volt signal to switch 240v for your heating.

I wouldn't like to comment on the quality of your electrics, but the timeswitch turns the heating on by connecting terminal 4 (CH ON) to the live supply internally via the relay. So if you take the wire from terminal 4 (CH ON) and connect it to the permanent live instead, this will have exactly the same effect, except that the heating will now be controlled by the room stat only, regardless of the setting on the CH side of the timeswitch.

 

[havetobelieve]

Thanks for explaining that in good detail. So from what I knew and you have told me:

I remove the CH ON terminal and connect this to the live terminal at the programmer instead. This I take it operates the white wire in the motorised valve when heating is selected on by the programmable room stat.

With the room stat, I connect the COMMON terminal to the new programmable room stat COMMON terminal, and the CALL to the call, and make safe the neutral at both ends?

 

[mogget]

Thanks for explaining that in good detail. So from what I knew and you have told me:

I remove the CH ON terminal and connect this to the live terminal at the programmer instead. This I take it operates the white wire in the motorised valve when heating is selected on by the programmable room stat.

That's right, the room stat switches the white wire to the three port valve. Previously, the timeswitch controlled the supply to the room stat so both the timeswitch and the room stat had to be 'on' for the white wire to go live.

Once you bridge the connection at the timeswitch, there will be permanent live to the room stat, which then switches the white wire all by itself. Because the actual thermostat is battery powered, there's no need for a neutral.

With the room stat, I connect the COMMON terminal to the new programmable room stat COMMON terminal, and the CALL to the call, and make safe the neutral at both ends?

Yes, but it's only necessary to terminate the neutral at the room stat, it doesn't need to be disconnected at the other end unless there's no space for a safe termination at the room stat end.

 

[havetobelieve]

thank you for helping me again and explaining.

please bare with me i have one final detail to confirm with you...

as the new prog. stat does not require neutral, do i just connect the common to the common in the new stat and call to the call (well what i am saying is the new stat doesn't have a call terminal is has a NO and a NC terminal as well as the C (COMMON)! I may sound stupid or idiotic here, but is NO terminal the SATISFIED terminal and the NC the call one? I want to get them right, but the terminology, etc is different for different makes/models and I am not as experienced as you of course)!!

And then of course as explained, cap off the old neutral wire that went to the old room stat.

 

[mogget]

Just been to have a look at http://www.sunvic.co.uk/tlx6501.htm as this normally open / normally closed stuff is a bit confusing for me too, and can confirm that the "N/O" terminal (normally open, break on temperature rise) is the one you want.

If you did accidentally use the wrong one, all that would happen would be that the heating would come on when it's warm and off when it's cold, about as much use as a lead balloon.

 

[havetobelieve]

thanks - been waiting for your reply really appreciate it mate.

ok, so let me get this straight and start with my work !!

the N/O is the call terminal and the N/C is the normally closed (sat terminal) so:

i shall remove the CH ON from the programmer and connect it to the programmer live terminal

then wire up the prog. room stat to: common (same as old stat) and call (to Normally open terminal) Then cap off the old room stat's neutral wire at the room stat end (using a bit of insulating tape).

then that should be done and new prog room stat in operation!??

 

[mogget]

That should do it.

 

[havetobelieve]

i am doing it now and the only thing i am a little worried about (maybe it's fine but i just want to check), is that is it OK to have 2 wires going into 1 terminal? i suppose you do when you spur off of a ring main, so maybe it's ok to do this to the programmer too?

 

[mogget]

as long as both wires are secure and aren't going to pull out, it should be fine. Sometimes you can put a little loop on the end so it goes round the screw and holds a bit better - but nothing's going to be tugging on them once it's all in place.