Thermostat can anyone help

[Laura Hardy]

Had a new thermostat put in with a new boiler and im unsure if its working correctly.
Temperature is set at 20.5
Room temperature is showing at 20
Heating is not coming on.
Its an esi model esrtp4rf
Should it not be sending info to the boiler as soon as it goes below the desired room temp ie 20.5?? Its been at 20 degrees for over 15 mins and nothing. The icons to show its transmitting are there.
I hope that makes sense

 

[Riley]

Put it higher a lot of them do not respond to 1/2°c increments

 

[ShaunCorbs]

Increase it 5 dc should fire

 

[Harvest Fields]

Leave it set at 22

 

[Laura Hardy]

Im guessing it has to be a difference of a full degree before it acknowledges it needs to fire up.

 

[Riley]

I think that’s what we all alluded to

 

[Laura Hardy]

Why does it do that then?

 

[Riley]

I would imagine because it’s too precise half degree is next to negligible in a property you wouldn’t feel the difference . I believe that a lot of thermostats actually have a waiver for accuracy sometimes to as much as + or -2°C

 

[ShaunCorbs]

I'm guessing it's battery powered

 

[Wirdy]

Thermostats are designed with a value called 'hysteresis' and is normally set to 1c or 2c to prevent the boiler cycling on & off too much. If it's a newer digital thermostat you can sometimes adjust the hysteresis value in the settings menu, but probably won't go below 1c.
As said above, if your boiler is not coming in until a difference of 1c or 2c between actual & desired temp is reached then your system is behaving normally.