Command 0x04 - Get Error State

This packet is occasionally sent by the MHK2 to retrieve error information from the heat pump.

Byte	Purpose	Possible Values	Supported by mUART	Notes
0	CommandType	0x04	Yes
4-5	Error Code	0x8000	Partial	0x8000 is "all clear", other values TBD
6	Two Character Code	0x00	Partial	User-friendly (?) error code 0x00 (A0) is "all clear"

Certain error codes have a textual representation at https://app.kumocloud.com/json/fault-codes.json. The two-character code needs to be mapped from hex to a specific display format.

The two-character-code will need to be converted from hex into a human-readable format, which may be done using the following sample code (n.b. requires validation):

def convert_two_char(code):
    upper_alpha = "AbEFJLPU"
    lower_alpha = "0123456789ABCDEFOHJLPU"
    
    return upper_alpha[(code & 0xE0) >> 5] + lower_alpha[code & 0x1f]