• Pipe sizes and lengths should be as the relevant Technical Guide
• Both lines should be insulated
• No line accessories or oil traps should be fitted
• In cooling mode both pipes should be between 0 and 10C - the suction line should sweat, but not freeze
• In heating mode both pipes should be between 30 and 60C
• Pipework should be refrigeration quality
• Look for restrictions. They could cause compressor failures.
• Discharge Temperature should be between 50 and 70C
• Suction Temperature should be between -3 and 4C
• Check Suction Line is sweating in cooling - problem if not!
• Hot Recip. Compressor = PROBLEM
• Sweating/Frost on expansion line - undercharged
• Is it level? Have we adequate drainage?
• Smells are always due to site conditions or drains.
• Flashing lights? = Fault Diagnostics - see over
• When were the filters last cleaned?
• Is the unit too large/small (between 5/20 air circs/hr)
• Is the air short cycling?
• Is it a wired or wireless handsets.
• Is the handset too far away?
• When were the batteries changed last?
• With wired handset, check for interference.
• Is the unit in Emergency Mode?
• Check unit and controller channels compatible
• Interconnecting comms wiring is low voltage
• If you have 230V live, check you have a neutral as well
• Check Mains and comms cable not swapped round
• Multi linked systems must be set up as such
• Check voltage drops! Check it isn’t down to Earth!
• Interconnecting cables should be circular crimped
Selecting Test Run
Every unit has an Emergency (marked Auto (Off/On) button.
Pressing this for less than five seconds initiates Emergency Operation.
Pressing this for seven seconds initiates Test Cooling.
Pressing this for ten seconds initiates Test Heating.
Wire E 1 2 3 4
Cool Only Earth Live Neutral N/A N/A
Heat Pump Earth Live Neutral Heating Defrost
Inverter Earth Live Neutral Comms N/A
Sensor Resistances - Use to check Thermistor
Sensor readings are the same for both indoor and outdoor units.
If the fault code suggests the sensor is a problem but you get
a sensor reaading as to the righ then either the Connection or
PCB is at fault.
Sensor At 10C At 20C At 30C
Indoor Air All 30K 0hms 18K 0hms 12K 0hms
Indoor Pipe All 40K 0hms 25K 0hms 16K 0hms
Outdoor Air Singles 30K 0hms 18K 0hms 12K 0hms
Outdoor Pipe Singles 10K 0hms 6K 0hms 3K 0hms
Compressor Singles 100K 0hms 60K 0hms 40K 0hms
All Outdoor Multis 40K 0hms 25K 0hms 16K 0hms
Fault Codes are only used on Inverter Systems. Both Single and Super Multi Inverter Systems use the same fault codes as below.
Outdoor Codes are ONLY used by the Super Inverter Multi systems models 23 and 27, NOT single systems.
When a Fault Occurs the Timer Lamp wil start flashing and the unit stops
Turning the Power Off will reset the unit but will not clear the fault code
The unit will remember up to three fault codes.
To fund the fault code
Ensure power is on at the unit and point the remote controller at it so a signal can be received
For single systems (CSE and CSXE) press the CHECK button for more than 5 seconds
For Multi systems (CSME) press the Timer Setting Up Arrow for more than five seconds
H11 will appear on the Remote Control Display - this indicates that Interrogate Mode is Operational
Use the Timer Setting Up and Down Arrows to scroll between fault codes until four beeps are heard - this shows the Fault Code
Fault Codes are cleared from memory by setting Test Cooling and shorting the RESET terminals in the controller battery compartment.
Code Outdoor LEDS - CU3E23 & CU4E27 Only Meaning Likely Cause
Reference LED 1 LED 2 LED 3 LED4
H11 Off Off Off Off Comms Failure Faulty Wiring or other problem with ID to OD communication
H12 Off Off Off Off ID/OD Compatibility Problem Over or Underindexed multi system
H14 Off Off Off Off Indoor Air Sensor Faulty Sensor Disconnected, Faulty or Contacts Dirty
H15 Off Off Off Off Compressor Sensor Faulty Sensor Disconnected, Faulty or Contacts Dirty
H16 On On Off Off Current Transformer Problem Power Transistor Module or Outdoor PCB Faulty. Very Low Gas
H19 Off Off Off Off Indoor Fan Motor Locked Fan Motor of Indoor PCB Failure
H21 Off Off Off Off Float Switch Operated Check Drainage
H23 Off Off Off Off Indoor Pipe Sensor Faulty Sensor Disconnected, Faulty or Contacts Dirty
H27 Off Off Off Off Outdoor Air Sensor Faulty Sensor Disconnected, Faulty or Contacts Dirty
H28 Off Off Off Off Outdoor Pipe Sensor Faulty Sensor Disconnected, Faulty or Contacts Dirty
H30 Off Off Off Off Outdoor Discharge Sensor 1 Faulty Sensor Disconnected, Faulty or Contacts Dirty
H32 Off Off Off Off Outdoor Discharge Sensor 2 Faulty Sensor Disconnected, Faulty or Contacts Dirty
H33 Off Off Off Off Incorrect Connection Voltage Indoor or Outdoor Voltage Incorrect/Faulty Wiring
H34 Off Off Off On Outdoor Heat Sink Sensor Faulty Sensor Disconnected, Faulty or Contacts Dirty
H36 Off Off Off Off Outdoor Gas Sensor Faulty Sensor Disconnected, Faulty or Contacts Dirty
H37 Off Off Off Off Outdoor Liquid Sensor Faulty Sensor Disconnected, Faulty or Contacts Dirty
H39 Off Off Off Off Abnormal Indoor Operation Incorrect Piping or Expansion Valve Problem
H41 Off Off Off Off Abnormal Wiring or Piping Wiring or Piping Crossed ona Twin System
H97 Off Off Off Off Outdoor Fan Failure Outdoor Fan Motor or PCB Failure
H98 On Off On On Indoor Coil Overheat (Heat Mode) Dirty Filters or Indoor Coil. Very High Room Temperature
H99 On Off On On Indoor Coil De-Ice (Cool Mode) Dirty Filters or Indoor Coil. Low Gas Charge or Low Ambient Temp
F11 On Off Off Off Reversing Valve Failure Faulty Reversing Valve, Coil or Outdoor PCB
F17 On Off On On Standby Units Freezing Multi Only. Expansion Valve Leakage
F90 On Off Off On PFC Failure Problem with Inverter or Compressor
F91 Off Off On On Refrigeration Cycle Problem Low Gas or Blockage
F93 Off On On Off Compressor Abnormal Revolution Compressor Running Incorrectly
F95 Off Off Off Off Outdoor Coil Overheat (Cool Mode) Dirty Condensor Coil, low gas or blockage
F96 Off Off Off Off IPM or Compressor Overheating Excess or Low Gas Charge or dirty heat exchanger
F97 On On On On High Discharge/Compressor Temp Low Gas Charge or Failed Compressor
F98 Off On Off On Overcurrent Protection Outdoor Heat Exchanger Problem. Excess Gas
F99 Off Off On Off DC Overcurrent Protection Outdoor PC, Power Transistor or Compressor Failure
None On On Off On Control Box Overheating Maintenance Required on OD Unit
For models CU3E23 & CU4E27 only there is a Green LED which normally flashes
If this is LIT then turn the power Off then On again. If it still does not flash the Outdoor PCB is Faulty.
If this is Off then there is a problem with the power supply