Runs fine (reliably) on cooling it should run fine on heating ie not a refrigeration problem.
You need to crank the remote setting right up to 28 or so on heat, turn it on then go outside and see what the outdoor unit does.
Does the outdoor fan run? Does the compressor start? When the indoor stops, do the louvres close up or stay open?
How long have you waited for heating to start before turning it off in disgust?
All splits will have an indoor preheat cycle to prevent a gust of cold air while the system gets going, anything from 3 to 10 minutes. The fan is triggered by the indoor coil temp sensor, typically a small bead attached to a well on the copper U bends. Make sure this is still in it's well.
If the sensor does not get to temp after a certain time the unit will fault. Causes are- Short of gas, no because it runs fine on cooling, or a dud coil sensor.
Like I said earlier, if the big pipe gets hot, then gas level is not too bad, fault is probably controls.
As with CT's you get what you pay for with AC units. Daikin, Mitsubishi, Fujitsu, Panasonic and dare I say it, Samsung are all good units.
Stay away from the cheapies if you can.