Replace mechanical satchwell tlx 2356 with siemens rdh10rf
- Thread starter netster
- Start date
Sponsored Links
Hi Dave, it is a wireless thermostat.
What I was asking was that "wireless" part of the electronics only concerns the communication between the receiver and the transmitter, and that the connection between the receiver and the central heating system should be the same as a wired thermostat? Or have I misunderstood..
I am probably confusing myself massively here, but what I understand is as follows:
With a wired thermostat, there is a temperature sensor, that controls a switch that switchs the central heating on or off.
With a wireless system, it is the same, except that the the temperature sensor is remote from the switch, communicating the temperature back to the switch wirelessly. I would then assume that once you get back to the switch part of things, wiring between the central heating and the switch is no different to a wired system?
My hope was that, wireless or otherwise, I am just replacing a switch that closes based on temperature, and to do that I just needed to know which wires we the live and the neutral (to power the swtich), which wire was the incoming live from the ch system, and which wire was the outgoing live back to the ch system. But from reading the thread it appears it is more complicated than this
Am I going mad?
If from my pics, it looks like there is no neutral, then can I assume that one wire is the live coming in from the ch system, one wire is the live going back to the ch system, and that the satchwell is just acting as a simple switch that completes the circuit above a certain temperature?
If so, am I right that what I could then do if I want a wireless thermostat, is to get a battery powered one ( so that there does not need to be power coming to the switch) and just connect up the live in and live out wires to the correct terminals?
All help appreciated, thanks
If so, am I right that what I could then do if I want a wireless thermostat, is to get a battery powered one ( so that there does not need to be power coming to the switch) and just connect up the live in and live out wires to the correct terminals?
All help appreciated, thanks
The wireless system will have a battery powered sender (the "stat") and a mains powered reciever that does the switching, which you connect it into the wiring center where an N will be available. I don't belive a 2 wire battery powered receiver exists, because neutral is always available at the wiring center.
If you want something simple to do a 2 wire replacement, your options are manual thermostat (a model not requiring a N, generally not as accurate) or a battery powered digital "combistat".
Sponsored Links
Thanks for all your help. I think I am clearer now.
Situation as I understand it as follows (for the benefit of any other newbie with a similar problem):
1. The wired/Wireless aspect for what I am trying to achieve is a red herring. It does not matter, it is the connection between the thermostat and the wiring centre that is important.
2. Putting the wireless controller to one side for a moment, if the thermostat itself is battery powered (I notice from a few other threads there are some models that are, which are recommended where a neutral is not available), then a two wire configuration to the wiring centre can work? (Please confirm)
3.) Otherwise, a neutral from the wiring centre needs to be brought to the thermostat, so that the thermostat can be powered. The live coming, in can be split to power the live terminal in the thermostat as well? (Please confirm)
Ok.
For my situation
I have the siemens RDH10RF which is the new thermostat I want to use, and has a wiring diagram as follows
http://picasaweb.google.co.uk/rmcdonald.lon/Thermo?authkey=FdcgfgP6Qs0#5269233318701425250
And my wiring centre looks like this (two pictures)
http://picasaweb.google.co.uk/rmcdonald.lon/Thermo?authkey=FdcgfgP6Qs0#5269232675575098850
http://picasaweb.google.co.uk/rmcdonald.lon/Thermo?authkey=FdcgfgP6Qs0#5269233106251359122
I can see clearly that only two wires are going from my wiring centre to the thermostat.
I also notice that my british gas engineer has left the earth wire loose in the wiring centre...
I would be grateful if someone could check this next bit for me:
To make the thermostat work, I am assuming I need to do the following:
1.) Use a 3 core cable
2.) Connect a neutral, to one of the Neutral terminals in the wiring centre (Which I have marked N in the picture) and run this through to the neutral terminal on the thermostat.
3.) Connect terminal 3 in the wiring centre to the live terminal in the siemens thermostat, and to the LX (common terminal) in the Siemens thermostat.
4.) Connect terminal 2 in the wiring centre, to the L1 terminal (item to be controlled) terminal in the siemens thermostat.
Is that right?
Situation as I understand it as follows (for the benefit of any other newbie with a similar problem):
1. The wired/Wireless aspect for what I am trying to achieve is a red herring. It does not matter, it is the connection between the thermostat and the wiring centre that is important.
2. Putting the wireless controller to one side for a moment, if the thermostat itself is battery powered (I notice from a few other threads there are some models that are, which are recommended where a neutral is not available), then a two wire configuration to the wiring centre can work? (Please confirm)
3.) Otherwise, a neutral from the wiring centre needs to be brought to the thermostat, so that the thermostat can be powered. The live coming, in can be split to power the live terminal in the thermostat as well? (Please confirm)
Ok.
For my situation
I have the siemens RDH10RF which is the new thermostat I want to use, and has a wiring diagram as follows
http://picasaweb.google.co.uk/rmcdonald.lon/Thermo?authkey=FdcgfgP6Qs0#5269233318701425250
And my wiring centre looks like this (two pictures)
http://picasaweb.google.co.uk/rmcdonald.lon/Thermo?authkey=FdcgfgP6Qs0#5269232675575098850
http://picasaweb.google.co.uk/rmcdonald.lon/Thermo?authkey=FdcgfgP6Qs0#5269233106251359122
I can see clearly that only two wires are going from my wiring centre to the thermostat.
I also notice that my british gas engineer has left the earth wire loose in the wiring centre...
I would be grateful if someone could check this next bit for me:
To make the thermostat work, I am assuming I need to do the following:
1.) Use a 3 core cable
2.) Connect a neutral, to one of the Neutral terminals in the wiring centre (Which I have marked N in the picture) and run this through to the neutral terminal on the thermostat.
3.) Connect terminal 3 in the wiring centre to the live terminal in the siemens thermostat, and to the LX (common terminal) in the Siemens thermostat.
4.) Connect terminal 2 in the wiring centre, to the L1 terminal (item to be controlled) terminal in the siemens thermostat.
Is that right?
Option 2 is easiest, and correct.
brown should be the switched live from the programmer, and blue the stat switched live feeding the zone valve.
therefore you'd need both mains permanent L and N for a wireless receiver, both of which are there in the wiring centre.
If the thermostat is programmable you won't need the existing progammer, you can make the brown a permanent live and yes, you'll need 3 active cores- L, N and switched live back to the valve
brown should be the switched live from the programmer, and blue the stat switched live feeding the zone valve.
therefore you'd need both mains permanent L and N for a wireless receiver, both of which are there in the wiring centre.
If the thermostat is programmable you won't need the existing progammer, you can make the brown a permanent live and yes, you'll need 3 active cores- L, N and switched live back to the valve
Thanks a lot Ben.
The unit is not programmable so I will be leaving the existing CH/HW programmer in place, I only intend to use the new thermostat as a thermostat, so probably would want to change any of the feeds/wires the programmer is receiving.
So I guess my final two option are:
1.) four core solution.
To use a 4 core cable, using two wires to bring the live from terminal 11 in the wiring centre, and the neutral for the terminal block marked N, through to the Siemens thermostat, and use terminal 3 & terminal 2 in the wiring to connect to the LX & L1 in the siemens.
2.) Three core solution
Pull a neutral through from the wiring centre to the thermostat.
(here is the bit I need confirmation on)
If I use the switched live, which is labelled COM (common? terminal 3 in the wiring centre) as the main live for the thermostat, is this a problem? I notice that term 3 is linked to term 9 which is the live from the heating system (not hot water), which I guess would mean:
a) this would only be live during the hours when the programmer is set to switch the heating on?
b) if this is the case, then this shouldn't be a problem, as we only need the thermostat to be active, when the central heating is actually on?
Is this right? Can I go for option two, and just use the existing 3 core wire, looping the live terminal in the stat, to the common (LX) terminal in the stat, or do I need to replace it with a 4 core wire?
Again thanks alot, as after your next reply, I am going to going and do this
The unit is not programmable so I will be leaving the existing CH/HW programmer in place, I only intend to use the new thermostat as a thermostat, so probably would want to change any of the feeds/wires the programmer is receiving.
So I guess my final two option are:
1.) four core solution.
To use a 4 core cable, using two wires to bring the live from terminal 11 in the wiring centre, and the neutral for the terminal block marked N, through to the Siemens thermostat, and use terminal 3 & terminal 2 in the wiring to connect to the LX & L1 in the siemens.
2.) Three core solution
Pull a neutral through from the wiring centre to the thermostat.
(here is the bit I need confirmation on)
If I use the switched live, which is labelled COM (common? terminal 3 in the wiring centre) as the main live for the thermostat, is this a problem? I notice that term 3 is linked to term 9 which is the live from the heating system (not hot water), which I guess would mean:
a) this would only be live during the hours when the programmer is set to switch the heating on?
b) if this is the case, then this shouldn't be a problem, as we only need the thermostat to be active, when the central heating is actually on?
Is this right? Can I go for option two, and just use the existing 3 core wire, looping the live terminal in the stat, to the common (LX) terminal in the stat, or do I need to replace it with a 4 core wire?
Again thanks alot, as after your next reply, I am going to going and do this
yes, of course, I'm thinking of prog. stats.
Plumbers do it all the time, as a class II plastic stat doesn't need an earth. so long as the core is sleeved up to notify it's a live cable and the flex is a short run that isn't buried in walls/under floors it's not terrible.
Myself I prefer to run a cable with enough cores and terminate the earth in a block.
Ben, thanks you very much for all your help.
I will put a proper explanation here in laymans terms, incase there are any other newbies that want to attempt a similar.
Objective: To replace an old mechanical thermostat with a new digital one. Additionally (but not important) the new stat has a wireless controller.
Important point to note: This is just to replace the thermostat, and NOT any programmable functions, as a different solution/wiring will be required for this.
The solution: The whole thing is just a switch!
1.) Power Off!! (This is important) Your old stat is likely to have 240v going into it (a point I almost did not consider), pretty much like a light switch, so do this before investigating further.
2.) The old thermostat. Wiring inside here is likely to be confusing when viewed on its own, as it may not be clear which wires are coming in from the wiring centre (the wiring panel inside your airing cupboard, or wherever the boiler/central heating controller is), or which wires are just internal to the thermostat itself. A better bet is to look inside the wiring centre itself first so you can see exactly how many wires are connected to the stat. (this is not nearly as scary as it sounds)
3.) The wiring centre.
With the power off, opening this up should be quite straight foward, and chances are this would have be updated from when the system was first installed (In my case a british gas engineer had replaced this a few years ago when fitting a new programmer). In any case you should see a wiring diagram inside the lid, which shows how the wires are laid out. The area of interest to you will be anything that points to the terminals where the wire going to your existing stat is located
You can see a picture of my wiring centre below, which showed my that terminal 2 & 3 were connected to my stat, and that a 3 wire (green & yellow) coming in from the stat, was left unconnected in my wiring centre).
http://picasaweb.google.co.uk/rmcdonald.lon/Thermo?authkey=FdcgfgP6Qs0#5269232675575098850
4.) Does your new stat need power?
If not (i believe there are a few model available which are completely battery operated), only two wires are needed then all you need to do is connect the live or common live as believe it is called, to the common live in your new stat, and connect the returning live wire in your stat, or the switched live as I believe it s called, to the returning live input in the wiring centre, basically this is the live that will being going back to the item to be controlled.And that's it.
If your stat does need its own power (as was the case for me) in addition to the live it will be switching on and off, then a cable with 3 wires are needed.
The problem for me was that the was no neutral coming into the original stat. To a newbie like me, "bringing a neutral" to the stat sounded like a big task, but it was very simple and straightfoward, and did not require running any extra cable.
Here is what I did.
The existing cable that ran between the Wiring C and the stat had 3 cores, (Brown,Blue & green/yellow).
Only the brown & blue were connected.
I connected the green & yellow to a neutral terminal in the wiring centre
I connected the brown wire (common live in the Wiring centre) to the Live terminal in the new stat. Now the stat has power.
I looped the live terminal in the new stat, to the common live terminal in the new stat (LX). Now the new stat has an incoming common live which it can switch.
I connected the switched live terminal in the new stat (L1) using the blue wire, back to the returing live in the wiring centre. I believe this is referred to as CALL and other names, but basically this is the live that will be connected to the device you want to control.
I did have a question as to whether it was ok to use the switched live coming in from the wiring centre, as the main live for the new stat, or did I need to locate a permanent live in the wiring centre.
The answer is it is fine to use the switched live, as in my situation, that live will be on when the programmer for the central heating is set to be on. Logically, the thermostat need only be doing its job when the timer for the CH is actually on. This way I did not need to run any new wires, and was able to use the existing 3 wire cable.
A point to note about your new mains powered stat. My one (siemens rdh10), does not need any setup if it loses power, so a switched live as the main live is no problem. If your device needs to be setup if it loses power, then a permanent live may be necessary for you, so that your stat has power even when the programmer has switched your CH off.
I know this is a bit of a long explanation, but it is aimed at the newbie, that needs a step by step.
Here is the short version:
Replacing the old mechanical stat, for a new digital stat - > YES it is possible and is quite simple.
1.) If your stat is battery powered, then just connect the common live that is in your existing stat, to your new stat, and your switched live, to the switched live in your new stat. There should be no need to disturb your wiring centre.
2.) If your stat requires power, then connect the common live (incoming live), to the live terminal in your new stat. Find the neutral terminal in your wiring centre (very straightforward), and connect this to the neutral in your new stat. Connect the switched live terminal in your new stat back to the wiring centre.
Job done.
Many thanks to hairyben
I will put a proper explanation here in laymans terms, incase there are any other newbies that want to attempt a similar.
Objective: To replace an old mechanical thermostat with a new digital one. Additionally (but not important) the new stat has a wireless controller.
Important point to note: This is just to replace the thermostat, and NOT any programmable functions, as a different solution/wiring will be required for this.
The solution: The whole thing is just a switch!
1.) Power Off!! (This is important) Your old stat is likely to have 240v going into it (a point I almost did not consider), pretty much like a light switch, so do this before investigating further.
2.) The old thermostat. Wiring inside here is likely to be confusing when viewed on its own, as it may not be clear which wires are coming in from the wiring centre (the wiring panel inside your airing cupboard, or wherever the boiler/central heating controller is), or which wires are just internal to the thermostat itself. A better bet is to look inside the wiring centre itself first so you can see exactly how many wires are connected to the stat. (this is not nearly as scary as it sounds)
3.) The wiring centre.
With the power off, opening this up should be quite straight foward, and chances are this would have be updated from when the system was first installed (In my case a british gas engineer had replaced this a few years ago when fitting a new programmer). In any case you should see a wiring diagram inside the lid, which shows how the wires are laid out. The area of interest to you will be anything that points to the terminals where the wire going to your existing stat is located
You can see a picture of my wiring centre below, which showed my that terminal 2 & 3 were connected to my stat, and that a 3 wire (green & yellow) coming in from the stat, was left unconnected in my wiring centre).
http://picasaweb.google.co.uk/rmcdonald.lon/Thermo?authkey=FdcgfgP6Qs0#5269232675575098850
4.) Does your new stat need power?
If not (i believe there are a few model available which are completely battery operated), only two wires are needed then all you need to do is connect the live or common live as believe it is called, to the common live in your new stat, and connect the returning live wire in your stat, or the switched live as I believe it s called, to the returning live input in the wiring centre, basically this is the live that will being going back to the item to be controlled.And that's it.
If your stat does need its own power (as was the case for me) in addition to the live it will be switching on and off, then a cable with 3 wires are needed.
The problem for me was that the was no neutral coming into the original stat. To a newbie like me, "bringing a neutral" to the stat sounded like a big task, but it was very simple and straightfoward, and did not require running any extra cable.
Here is what I did.
The existing cable that ran between the Wiring C and the stat had 3 cores, (Brown,Blue & green/yellow).
Only the brown & blue were connected.
I connected the green & yellow to a neutral terminal in the wiring centre
I connected the brown wire (common live in the Wiring centre) to the Live terminal in the new stat. Now the stat has power.
I looped the live terminal in the new stat, to the common live terminal in the new stat (LX). Now the new stat has an incoming common live which it can switch.
I connected the switched live terminal in the new stat (L1) using the blue wire, back to the returing live in the wiring centre. I believe this is referred to as CALL and other names, but basically this is the live that will be connected to the device you want to control.
I did have a question as to whether it was ok to use the switched live coming in from the wiring centre, as the main live for the new stat, or did I need to locate a permanent live in the wiring centre.
The answer is it is fine to use the switched live, as in my situation, that live will be on when the programmer for the central heating is set to be on. Logically, the thermostat need only be doing its job when the timer for the CH is actually on. This way I did not need to run any new wires, and was able to use the existing 3 wire cable.
A point to note about your new mains powered stat. My one (siemens rdh10), does not need any setup if it loses power, so a switched live as the main live is no problem. If your device needs to be setup if it loses power, then a permanent live may be necessary for you, so that your stat has power even when the programmer has switched your CH off.
I know this is a bit of a long explanation, but it is aimed at the newbie, that needs a step by step.
Here is the short version:
Replacing the old mechanical stat, for a new digital stat - > YES it is possible and is quite simple.
1.) If your stat is battery powered, then just connect the common live that is in your existing stat, to your new stat, and your switched live, to the switched live in your new stat. There should be no need to disturb your wiring centre.
2.) If your stat requires power, then connect the common live (incoming live), to the live terminal in your new stat. Find the neutral terminal in your wiring centre (very straightforward), and connect this to the neutral in your new stat. Connect the switched live terminal in your new stat back to the wiring centre.
Job done.
Many thanks to hairyben
I would recommend a wireless device (it does not affected the setup mentioned below)
The problem I have now solved, was
a.) The original thermostat was stuck
b.) The original thermostat was situated just outside the cupboard with the boiler in it, meaning that I had to turn the thermostat up to the max all the time to get the thing to come on at all, which would then mean my flat was either boiling for freezing.
The wireless device, has allowed me to put the temp sensor, in a much more sensible part of the flat, with an average temperature
The problem I have now solved, was
a.) The original thermostat was stuck
b.) The original thermostat was situated just outside the cupboard with the boiler in it, meaning that I had to turn the thermostat up to the max all the time to get the thing to come on at all, which would then mean my flat was either boiling for freezing.
The wireless device, has allowed me to put the temp sensor, in a much more sensible part of the flat, with an average temperature
A small point depending on the features of wireless controller you have.
As mentioned before, when the central heating timer shuts down, the live to the stat is switched off. Not a problem as you don't need your stat to be active when the central heating is off.
When the power comes back on, my stat fires back up just fine, but I notice that the wireless temperature does not send the call for heat to the stat, so the switch remains off/open.
A permanent live will solve the situation for me, but may not be necessary for a different wireless model.
As mentioned before, when the central heating timer shuts down, the live to the stat is switched off. Not a problem as you don't need your stat to be active when the central heating is off.
When the power comes back on, my stat fires back up just fine, but I notice that the wireless temperature does not send the call for heat to the stat, so the switch remains off/open.
A permanent live will solve the situation for me, but may not be necessary for a different wireless model.
Hi netster
I'm replacing a siemens programmer with a new wireless siemens programmable stat. (RDJ10RF)
My boiler is plugged into the wiring system
The wires i have coming in are L N E and a black wire (not sure what this is. Common?).
On the new stat receiver i've got L and N terminals and also L1 L2 and LX.
This is where i'm stuck. I can connect L and N to give the receiver power but don't know what to do with the other terminals
Any help would be greatly appreciated
Thanks
I'm replacing a siemens programmer with a new wireless siemens programmable stat. (RDJ10RF)
My boiler is plugged into the wiring system
The wires i have coming in are L N E and a black wire (not sure what this is. Common?).
On the new stat receiver i've got L and N terminals and also L1 L2 and LX.
This is where i'm stuck. I can connect L and N to give the receiver power but don't know what to do with the other terminals
Any help would be greatly appreciated
Thanks
Ian, start a new thread of your own and dont add to old posts.
I've just read through two pages of year old stuff to get to your hijack.
I've just read through two pages of year old stuff to get to your hijack.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
Similar threads
