Siemens RDJ10 room thermostat

[Helen Young]

Hi, hope someone is able to help. I’ve recently turned my heating on and read the instructions for the Siemens RDJ 10 thermostat repeatedly so they’re no stuck in my brain(!)
I’ve set it so the temperature should be 20.5 degrees, problem is it’s only getting to 18. I don’t understand why
My boiler is working and fires up when I want hot water but the heating and radiators are never hot like I would expect when I’m asking for heat. It’s been on all day today and still luke warm radiators and wearing a jumper. please could someone help?

 

[oldbuffer]

1. Do you have thermostatic valves on the radiators? If so, are they set to around 4 (approximates to 20 - 21 degrees)?
2. What is the central heating temperature on the boiler set to?
3. What boiler and controls do you have?

 

[CBW]

What position is the slider in and have you checked if it’s the batteries?

 

[stem]

The thermostat is simply a switch. It turns the heating 'on' and 'off' and that's all it does. A small triangle symbol in the display shows when the thermostat has switched 'on'. If the symbol isn't present, that means it has switched 'off'.

So, if the thermostat has turned the heating 'on' and the boiler is running and is continuing to do so, it's doing it's job and can do no more. Provided that it doesn't switch the heating off until the set temperature (in your case 20.5 degrees) in the room where it is located is reached. How warm your home actually gets will then depend upon how well the heating system is performing.

If the thermostat is turning the heating off before 20.5 degrees, have you checked that the thermostat is in comfort mode (Sun symbol showing) and not setback mode (Moon crescent symbol showing)? The set back mode is used to reduce the temperature by a few degrees during the night or when the premises is unoccupied.