Boiler firing up when room stat is not calling for heat?

Hello,

Hope someone can help? I've had a sales wireless programmable thermostat installed and when tested by putting target temp up and down it works perfectly and boiler fires up and shuts down as it should. However when then left alone the boiler seems to fire up every few mins even though the room stat is satisfied and not calling for heat. Is this normal or is something not right?

Thank you in advance