Aircommand IBIS ROOFTOP CARAVAN, Technical Manual

Page 5

           Resistance to earth minimum 20 Meg 

Ω

5: On cooling mode, compressor and outside fans stop.

Unit ceases to cool but display temp. drops to a low figure. Maybe 

less than 10C.

This is typical of an inside coil icing up. The thermistor detects that the coil

is at or below zero and turns off the compressor until temp. rises to 12C, 

Whereupon the compressor will restart.

This situation is usually associated with the unit running for a prolonged period 

on low fan speed particularly in high humidity conditions.

This problem is usually overcome by running the unit on a higher speed and not 

using ‘Auto” fan.

Check also that the return air filters are clean.

In heating mode, the unit stops heating, inside fan stops, and the red heat LED blinks.

This condition indicates that the unit has entered the de-ice mode to rid itself of frost on the 

outside coils. The unit will restart automatically in 5 to 10 minutes.

It may be noted that the display temp drops to a low figure.

On resumption of heating, the blinking red light turns to a steady red, and the 

inside fan start will be delayed until the inside coil is warmed to 32C. When the inside fan does 

start there may be a momentary puff of vapour. This is normal.

7:  In very cold conditions the compressor can be heard running but the inside fan does not start.

Be patient, in very cold conditions the unit needs time to warm sufficiently to start producing 

warm air.

8:  Compressor transmits excessive vibration.

Check that the top washer of the four compressor studs are clear of the rubber 

Mount by 1 to 2 mm. Adjust if necessary. See fig 7

9: On heating, the unit cycles regularly, the temperature display indicates say 24 to 28C but the average 

temperature in the van is very much less.

Disassemble the facia from the inside plenum (4 screws) and examine carefully 

the extension duct for leaks, particularly where it joins the horizontal duct.

A leaking duct will short cycle warm air onto the return air sensor causing the compressor to 

close down prematurely.

            Repair any leaks and reassemble. (see Fig 10 and 24)

10: On cooling, the unit cycles regularly, the temperature display indicates say 22 to 25C but the 

average temperature in the van is very much more.

Disassemble the facia from the inside plenum (4 screws) and examine carefully 

the extension duct for leaks, particularly where it joins the horizontal duct.

A leaking duct will short cycle cold air onto the return air sensor causing the 

compressor to close down prematurely.

            Repair any leaks and reassemble. (see Fig 10 and 24)

11:  Water drips from the inside plenum when the unit is in cooling mode.

Ingress of water on cooling mode may be due to either of four conditions.

1: The unit is installed more than 5

°

out of level, particularly nose down.

2: The drain holes in the evaporator area are blocked. See Fig 8

3: Condensation that has drained onto the roof, has re entered the installation hole either 

under the roof seal of the airconditioner or a roof seam near the unit is faulty. If case 3 

appears likely, the unit should be reinstalled using a new sealing gasket and following the 

Aircommand instructions explicity.

    If there is a roof seam involved, clean the seam area thoroughly and reseal