The "Inverter Phase Check Module" is the perfect low cost answer to a Contractor's problems when an inverter-controlled air conditioner fails. The difficulty is always to know whether it is the compressor or the inverter which is giving trouble - and the Inverter Phase Check Module can help to tell you which is faulty. The supply connections are disconnected from the compressor, and are connected to this module. When the inverter is switched on the six lights on the module should light up Red, Yellow and Blue. If the inverter PCB is faulty, one or more of these lights will not switch on, and this indicates the position of the fault. It's that simple! If all six lights are on, the PCB is fine, and the fault is with the compressor. If they are not all on, or one light is significantly dimmer than the rest, then the fault is with one or more of the output transistors on the PCB, or with the drive circuitry. The "Inverter Phase Check Module" is small enough to drop into the toolbox, and will always help with the analysis of problems on site. A Kit of connection leads are available for use with this indicator. The three leads are each 1 metre long and fitted with insulated 1/4" female Fastens for connection to the indicator box. The "Inverter Phase Check Module" and the Connection Leads are designed to comply with the CE Low Voltage Directive when used as directed on the Instruction leaflet. Although small, it is not intended to be hand-held, and of course all power supplies must be safely turned off while the module is being connected.