The remote control for NEC split air con RSH-2647 does not seem to work properly. I changed the batteries and made it working a bit but then it started to play up again. It switches the unit on, the compressor light is on but then goes off and there is no heat. Sometimes I cannot even it move it to the sun. Can you advise what can be wrong. It does not seem to be anything wrong with the unit itself, more looks like remote control. Would new remote control help?