Carrier 50VZ Installation, Operation And Maintenance Instructions

Also see for 38PZ: Installation manual Installation manual

Carrier 50VZ Installation, Operation And Maintenance Instructions Manual pdf 29 page image

29NOTE 1: This control is compatible with any kind ofelectromechanical or electronic control (without anticipationresistors) with the following features:- Voltage at 24 V AC50VZ units standard connections:R Connection to 24 VL Protection device indicationC Common 24 VG VentilationY1 First stage coolingY2 Second stage coolingW1 First stage heating (option)W2 Second stage heating (option)50PZ units standard connections:R Connection to 24 VL Protection device indicationC Common 24 VG VentilationY1 First stage (cooling/heating)Y2 Second stage (cooling/heating)W1 First stage heating (option)O Reversing valve** The O connection is activated in cooling.NOTE 2: If the thermostat wiring is incorrect, the control willbe blocked (red LED on) and all the outlets will be deactivatedwhen unit power is supplied.NOTE 3: The thermostat cables should be separate from any220 V or 380 V cable.Refrigerant line connections (38VZ/PZ and 40PZ)To guarantee correct unit performance ensure that the linelength and number of bends are kept to a minimum. Avoid pipekinking by using large radius bends.IMPORTANT: Always use refrigerant-grade deoxidized anddehydrated copper tubing between the indoor and outdoorunits.Before connecting the refrigerant lines carefully follow thesteps below:- Remove the nitrogen holding charge from the refrigerantcircuits.- Select the diameter of the copper tubing according the theunits installed and according to the distance between theindoor and outdoor units.- Use silver alloy rod for soldering purposes, and ensurethat this work is done in a nitrogen atmosphere.- To avoid oxidation insulate the refrigerant linesadequately.- Pull a vacuum in the refrigerant circuit until a pressure of6.9 Pa is maintained for at least 2 hours.- Charge the refrigerant circuit with the necessary amountof R-407C refrigerant (in accordance with table 1 and thelength of the refrigerant lines).- Check there are no refrigerant leaks.Refrigerant line selectionGeneralWhen designing refrigerant lines the following must be kept inmind:- Depending on the unit arrangement:Fig. 22 - Refrigerant lines option AHeat pump (discharge line)Outdoor unitIndoor unitHeat pumpLiquid lineCoolingGas lineCooling (suction line)Suction/discharge line:- A siphon at the base of the vertical pipe run and inter-mediate siphons every 8 m or oil separators are needed.- Most unfavourable condition: the suction speed in thevertical pipe run must be more than 6 m/s.Fig. 23 - Refrigerant lines option BHeat pump (discharge line)Outdoor unitIndoor unitHeat pumpLiquid lineCoolingGas lineCooling (suction line)Suction/discharge line:- For heat pumps a siphon is required in the base of thevertical pipe run.- The intermediate siphon can be omitted.- For cooling only units siphons are not required.- Most unfavourable condition: the suction/dischargespeed in the vertical pipe run must be more than 6 m/s.