The error code 'E1' means that your indoor and outdoor units are having problems communicating with each other.
In order to fix this you can; check that all of the connections are clean and tight, that there is no corrosion on the connections - if so you can use light abrasive paper to clean each one; check to see if the connections are connected to the correct place, there are wiring diagrams printed inside the indoor and outdoor unit's PCB case; check for any breaks in the black communication wire, if 'chock blocks' or 'rotary isolators' are used then you can check if the connection are properly connected - and the isolator is turned on.
ANY WIRING OR CLEANING OF CONNECTIONS REQUIRE THE POWER TO BE ISOLATED BEFORE WORKS COMMENCE.
After checking all the connections, that they are all clean, tight and correct, then it means that the problem is with the PCB. You will need to replace the PCB. You can contact us for a new PCB via email at info@airconditioningcentre.com or call us at 0370 3344 556.