Using an indoor air conditioner with a broken outdoor unit

During the Daniel extreme flood event in Thessaly, I was fortunate not to lose anyone, but sustained material losses, including two cars and my air conditioners’ outdoor units, which were submerged for two days and destroyed. The internal units were safe, and I wondered if they could function independently for fun. It turns out that any internal air conditioner unit can operate as a fan without the need of an external unit.

The first thing to do is try to find a schematic. My indoor unit included a diagram showing the internal ports, with three wires (Brown, Blue, Orange) plus ground coming from the outdoor (OD) unit. 

According to the schematic, my gut feeling was that the orange cable is likely the signal line for command transfer, while the brown and blue are standard power wires. 

I stepped outside to find the repairmen had removed the outdoor units, leaving cables exposed. My setup included gray, brown, black, and ground (yellow-green) wires from the outdoor to the indoor unit: black connected to the orange port 3, gray to the blue port 2, and brown matched with its color on port 1. 

I also had a power supply with brown, blue, and ground (yellow-green) wires, which would have connected to the outdoor unit if it were still there. 

Based on my instincts, I hot-wired the pairs and left the signal cable, the black one, which connects to orange in port 3, untouched. 

After confirming my power protection relays were working properly and my fire extinguisher was ready, I switched on the fuse to power up my monstrosity. I used the remote to select fan mode, and everything operated smoothly! The indoor unit can circulate air around the room, but it won’t cool or heat the space without the outdoor unit, since refrigeration can't happen. In fan mode, the system functions just like an ordinary fan, simply moving air without changing its temperature. If you try to switch to another mode, the device may get stuck, requiring you to cut the power to reset it. 

Since the experiment was successful, the final step is to rewire the indoor unit so it can be plugged directly into a standard power outlet using a regular power cable, with the signal port left disconnected as illustrated below. 

Please, always verify the wire colors carefully!!! In a different unit, the installer had mismatched the colors completely and my experiment would have gone terribly wrong. As Einstein supposably said, “Two things are infinite: the universe and human stupidity; and I’m not sure about the universe!”