The master board incorporates a supply and measurement unit and one rack unit into which each module can be quickly fastened or removed. Measurement instruments section consists of: · Low Pressure gauge 0-300 P.S.I. · High Pressure gauge 0-500 P.S.I. · 1 x Hermetic compressor for R-134-A gas, · 1/8 HP minimum; 220 Watt Cooling capacity minimum, · 1 x Condenser, rejection heat, 430 Watt minimum, · 1 x Gas receiver, · 1 x Gas filter drier, · 1 x Sight glass (visor) · 3 x Pressure transducer · 4 x Temperature transducer · 1 x Reversing valve · 1 x Computer Interface for each A/C software operating package · 1 x Communication error indicator The electric power supply section consists of: · Input voltage 220/115V AC, 50/60 Hz · Output Voltage 24DC · Safety earth leakage relay (ELR) · Main electric switch