My Gree AC is showing an H, E or F code — what do the common ones mean and which need a pro?

Gree does have a logic, and reading it first saves a wasted call-out. The first letter tells you the area: H = protection and status, E = pressure/protection, F = sensors, U = communication. A few of the most common ones and what they usually indicate: H1 is actually the unit DEFROSTING, which is normal, not a fault, so if it clears itself nothing is wrong; H3 is compressor overload protection; H5 is the power module (IPM) protecting itself; E1 is high-pressure protection; E2 is freeze protection; F1 and F2 are indoor sensor faults (ambient and evaporator). The honest caveat: exact meanings can vary by model, so your unit manual is the final authority on any code. On priority: many H-codes clear on a proper power-cycle (off at the isolator for a few minutes), and sensor faults (F-codes) are usually a straightforward component replacement, BUT E1 high pressure, H3 compressor overload and H5 power-module codes point at pressure, compressor or board problems and should stop you running it and get a professional, because running on those risks real damage. Same read-the-code-first logic as the Daikin and O General threads and the general error-code guide. If a protection code keeps returning after a restart, AC servicing in Dubai can read it on the tool and confirm. Photograph the code before you clear it.