Myson Touch?

Myson Touch thermostatic controller.
My mums new build has the Touch 2 upstairs which controls upstairs rads & hotwater. All good.
Downstairs she has underfloor heating and ‘Touch’ thermostat. She’s adjusted the room temp ^ to 20°, presses ‘done’. The flame icon is on the screen but there’s no raise in the temperature, it’s not working.
Any ideas anyone please? Her room temp is around 14.5° at the moment!