I have Delonghi portble air conditioner which I have since 3 years. Now this winter when I started using it as heater, it randomly shuts down wth 5 or so beeps and then shows only error triangle, no error code other than the triangle. Then it starts again only if i tilt it 20 degrees forward for a second. Then it works may be an hour or two and shuts down again. Resetting the safety switch does not help. Only tilting helps. Already drained half glass water it had in the drain tank.

Any thoughts what might be going on?

Why would you get water from a heat cycle? With AC I could see some. IF the unit isn't perfectly level, the safety will trip. Since you are getting water from some place, make sure it isn't tripping a water level switch. If you Google the model and make, you can find a lot of info. Your owners manual should show you trouble codes or symbols. If the unit has a filter, make sure it is clean.