I am after a bit of advice to do with CH Thermostats. At the moment we have an antique looking Satchwell TLX 2259 and i dont think its very accurate at all so i would like to replace it with a digital thermostat before the weather gets cooler.

The old thermostat has 3 wires going to it; yellow, red, blue. Is there anything i need to take into account or is it just a case of buying a new thermostat and wiring it up?

I am after a bit of advice to do with CH Thermostats. At the moment we have an antique looking Satchwell TLX 2259 and i dont think its very accurate at all so i would like to replace it with a digital thermostat before the weather gets cooler.

The old thermostat has 3 wires going to it; yellow, red, blue. Is there anything i need to take into account or is it just a case of buying a new thermostat and wiring it up?

The three wires will be phase, neutral & control - get a meter across to find check which is which PROBABLY red = phase, blue = Neutral & Yellow = control.

If earthed you can detect all above easily.

Then look up specs for digital types and go from there.

I am after a bit of advice to do with CH Thermostats. At the moment we have an antique looking Satchwell TLX 2259 and i dont think its very accurate at all so i would like to replace it with a digital thermostat before the weather gets cooler.

The old thermostat has 3 wires going to it; yellow, red, blue. Is there anything i need to take into account or is it just a case of buying a new thermostat and wiring it up?

Hi Alex

Another thought before you get just a Thermostat, we have one that has a timer built in, so it will control the time it comes on and off as well as the temp !

Also some of the newer thermostats don't need mains to operate, so watch out, as your system might not allow this type of stat.

Radiotwo

Do a lot of research as some of the new digital stats actually "learn" how long it takes your room/house to warm up and cool down...I have one and it is battery powered but does switch mains as well, it seems to keep the room to an even temp and stops constant cycling on and off so in theory will save power as well

http://aunz.siemens.com/Environment/CC/Products/Documents/REV11_Data_sheet.pdf

I just bought and fitted one of these this week....

http://www.screwfix.com/prods/17585/Plumbing/Central-Heating-Controls/Horstmann-DRT2-Room-Thermostat

If you get similar you only need to connect the yellow and red wires,the blue(neutral)is not required in this case.The instructions that come with the new stat will tell you what is required. On the Screwfix web page you can also download the instuctions which might help.

I bought the above as a mate at work bought one last year,and as I normally leave the heating on contant and turn the stat up during the day and down a bit at night,thought this would be ideal for me. This new stat is progammed to come on in the morning at say 6am @ 20 deg. 8.30am it turns down to 16, goes back up to 20 at 1600hrs till 10pm where it goes back to 16,all of which can be set to your requirements.All in all a not bad bit of kit. And it controls to +/- 1 deg unlike my old mechanical effort,which probably was more like +/- 5 deg.I did look in B&Q as they have two similar items that were £30 odd reduced to £10,but none of my local branches had any,and looking at the diplay model they were a bit big anyway.

Hi Alex

Another thought before you get just a Thermostat, we have one that has a timer built in, so it will control the time it comes on and off as well as the temp !

Also some of the newer thermostats don't need mains to operate, so watch out, as your system might not allow this type of stat.

Radiotwo

We have a fairly new heating/hot water timer that's all digital and works well. Just have a dilapidated thermostat, why the previous person didn't change the two when the timer was replaced i don't know.

So i have been looking at the Siemens RDH10, from the following PDF instruction manual can anyone tell me which wire would go to which terminal and is it even compatible?

p4766730.pdf

So i have been looking at the Siemens RDH10, from the following PDF instruction manual can anyone tell me which wire would go to which terminal and is it even compatible?

p4766730.pdf

Hi Again

That one will only work if your system works without Mains voltage on the stat, you did say yours was a fairly new system, so might be ok, but check on your wires, I think you said Yellow, red, and blue, you need to check with a meter and see if there is 240 volts on any wires, if so that unit will not work.

Radiotwo

Hi Again

That one will only work if your system works without Mains voltage on the stat, you did say yours was a fairly new system, so might be ok, but check on your wires, I think you said Yellow, red, and blue, you need to check with a meter and see if there is 240 volts on any wires, if so that unit will not work.

Radiotwo

Don't understand that comment - the posted pdf appears to be an isolated change over relay that can switch 24-250v at 5A, so in my opinion would be ok

See http://www.tlc-direct.co.uk/Technical/DataSheets/Sunvic/TLX.pdf for wiring of your current stat. This suggested L is T3, SwL is T1 and T4 is N

Aledgedly, the neutral is there to operate a pre heat resistor to prevent large swings in room temp, so fitting the L & SwL accross LX and L1 of the Siemens should do it. Do not connect the netral wire, (if the live is on LX, L2 will be live when the room is up to temp) just leave it un-insulated and preferably exposed (or use a choc block and then insulate - your choice )

As above connect red and yellow wires to Lx and L1,tape up the blue (neutral) as it is not required.

First Q --Room to be monitored - most rooms to set the temperature are those that the installer decode was easiest .So go looking for the best room .

Cheers for the help guys! Fitted my siemens rdh10rf this morning.

Was a little confusing as it needs a constant live, but i sorted it

Hi,

I am going to attempt changing my TLS2259 for a Siemens RDH10.

Did you wire it like the following?

Wire in TLX2259 Terminal 3 goes to RDH10 terminal LX

Wire in TLX2259 Terminal 1 goes to RDH10 terminal L2

Cheers

Cheers for the help guys! Fitted my siemens rdh10rf this morning.

Was a little confusing as it needs a constant live, but i sorted it

Ok, I installed the RDH10 last night and found the wiring was

Wire in TLX2259 Terminal 3 goes to RDH10 terminal LX

Wire in TLX2259 Terminal 1 goes to RDH10 terminal L1

Ok, I installed the RDH10 last night and found the wiring was

Wire in TLX2259 Terminal 3 goes to RDH10 terminal LX

Wire in TLX2259 Terminal 1 goes to RDH10 terminal L1

What did you do about the live and neutral terminals?

I had to loop a bit of wire from LX to the Live to get it to switch on.

Right sorry to resurrect an old topic but yesterday we had an rdh10 fitted along with our new boiler. And am completely lost on how to use it :-(

Could anyone who has one of these please help me on how to use this unit. Simple terms only please

I'm mainly stuck with the meaning of comfort setting (the sun) and energy saving setting (the moon)

Any help will be gratefully appreciated

Wayne