Aircommand - IBIS Rooftop caravan air-conditioner – Error codes cause and solution

BIS Rooftop caravan airconditioner

Error codes causes and solution
Error code - E1

Room sensor fault. Usually a faulty connection (plug), damaged lead or a faulty sensor itself.
Solutions

Check White plug is connected on main board. Check resistance of thermistor & cable by measuring with a multimeter. 10K ohm @25C. If open circuit or out of calibration, replace.
Error code - E2

Inside coil sensor fault: Usually a faulty connection (2 plugs) Damaged lead or faulty sensor.
Solutions

Check Yellow plug is connected on the main board. And also plug in bundled wiring near the coil.
Check resistance of thermistor & cable by measuring with a multimeter. 10K ohm @25C. If open circuit or out of calibration, replace. When replacing this thermistor, install such that cable is downward from the copper pocket on the coil.
Error code - E3

Outside coil sensor fault Usually a faulty connection (2 plugs), damaged lead or faulty sensor.
Solutions

Check Red plug on main board and extension plug in bundled wiring usually located near capillary tube coils. Check resistance of thermistor & cable by measuring with a multimeter. 10K ohm at 25C. If open circuit or out of calibration, replace.
Error code - E4

Indicates lack of refrigerant, or the compressor is not running, or the thermistor is out of calibration.Solutions

Check that the compressor is running by listening.
If it is apparent that the compressor is running, then check the temperature difference across the evaporator. i.e. Measure temperature of return air at inlet filters and measure temp. of discharge air at grilles. This temp diff. should be 14 to 18 C. with fan on hi speed. If temp diff. is less than this, suspect lack of refrigerant.
Fit a suction gauge to access valve at rear of unit. On a 35C outside temp. then suction should be 380 to 450Kpa.

If the temp. differential is 14C or more but unit goes out on E4 after approx. 30 minutes, please check the actual thermistor temperature by the following procedure. With the inside fan running on Hi, Press Temp down button followed by the mode button. Hold them both in for approx 5 seconds. The amber Lock LED illuminates. Now press the Temp down button and the Sleep button Together for about 1 second. The green Med speed will be Flashing. The display is now reading the temp of the outside coil. Now press the Temp up button once. The Green Hi speed will be flashing. The display is now reading the temp. of the inside coil.
This temp will usually be from 5 to 12 C. If it is above 24C. It is another indication of lack of refigerant. If on the other hand the air on /air off differential is 14C or greater then suspect the thermistor itself to be out of calibration. Check the thermistor as per an E1,E2 or E3 failure by measuring its resistance.

Error code - E5

Indicates excessive temp. of the outside coil if on cooling, OR excessive temp of the inside coil in heat mode. On cooling, the E5 will appear if the outside coil temp exceeds 68 Degree C. This is an indication of condenser airflow reduced or non-existent. Using the procedure described above it is possible to watch the condenser coil temp using the Temp down button and Medium fan speed combination to display this temp. NB: if fans etc seem to be OK then measure thermistor resistance. 

Solutions

 If unit is in cooling mode, examine both condenser fans are running. If one is running then suspect a faulty motor. If both fans not running then on units up to serial No. IBSA 01175, investigate the fan speed control card located in enclosure on the LHS.
If this checks OK then investigate main control card. Units with serial No’s and onward are multi speed tapped wound motors not requiring a speed control card. If both motors inoperative then suspect main control card.
If unit is in heating mode, examine the indoor fan that it is free to rotate.
If fan is inoperative but free to rotate, then. Units up to S/N IBSA01175, examine speed control card. If OK then examine fan motor & capacitor.
Winding resistance: 

Blue /Black approx 165 Ohms

Blue / Brown approx 480ohms

If after S/N IBSA01175, check winding resistance
Blue /Black 580 ohms
Blue /Grey 630 ohms
Blue /White 685 ohms
Brown/Yellow ohms
If fan motor and capacitor check out OK then change the main control board.

Error codes E6 & E7 are not utilised in this system. If either of these codes appear, then change the main control board