McQuay SWP Series Installation And Maintenance Manual page 43

R-407C leaks
R-407C is a zeotropic blend of three HFC refrigerants (R-32,
R-125, and R134a). Zeotropic blends do not behave as one
substance. Therefore, a change of phase does not occur at a
fixed temperature. R-407C has a "glide" of 8°F because it
boils and evaporates over a 8°F change in temperature.
If an R-407C unit leaks refrigerant, there is no way to
determine how much of each of the three component
refrigerants has leaked. However, experience in the field
shows that R-407C can be "topped" off after a leak and operate
normally. There is no need, except in the case of critically
charged systems, to replace the entire charge after a leak.
When recharging or topping off a system using R-407C, it is
important to remove the refrigerant from the charging cylinder
in the liquid phase. Many of the cylinders for the newer
refrigerants use a dip tube so that in the upright position, liquid
is drawn from the cylinder. DO NOT vapor charge out of a
cylinder unless the entire cylinder is to be charged into the
system. Refer to charging instructions provided by the
refrigerant manufacturer.
Adding refrigerant to the suction must always be done by
trained service personnel that are experienced with the risks
associated with liquid-related damage to the compressor.
McQuay IM 937
CAUTION
System Check, Test, and Start
Figure 41: Water and Refrigerant Piping Schematic
RELIEF
VALVE
RECEIVER
CONDENSER
SUCTION
DISCHARGE
VALVE
VALVE
COMPRESSOR NO. 1
RELIEF
VALVE
RECEIVER
CONDENSER
SUCTION
DISCHARGE
VALVE
VALVE
COMPRESSOR NO. .2
RELIEF
VALVE
RECEIVER
CONDENSER
SUCTION
DISCHARGE
VALVE
VALVE
COMPRESSOR NO. 3
RELIEF
VALVE
RECEIVER
CONDENSER
SUCTION
DISCHARGE
VALVE
VALVE
COMPRESSOR NO. 4
LOW
WATER FLOW SWITCH
HIGH
E.S.
WATER
COIL
12'
Variable Air Volume (VAV) Start-Up
Enter the duct static pressure set point value and parameters
through the keypad:
SAF Spd Control
DuctSP Spt=
When the appropriate number of VAV terminal boxes are
opened by setting down their respective thermostats, the VFD
should go to the maximum airflow. Upon closing enough VAV
boxes by setting their respective thermostats up, the inlet VFD
should go to the minimum airflow position.
RPM Changes
All units are provided with fixed pitch sheaves selected for the
specified operating conditions. If a new fan rpm selection is
required, field install a new sheave selection. Adjust the belt
tension as described below.
SIGHT
ISOLATION FILTER
ISOLATION
GLASS
VALVE DRIER
VALVE
EQUALIZER
CAPILLARY
EVAPORATOR
A- A EXPANSION
VALVE
SIGHT
ISOLATION
FILTER
ISOLATION
GLASS
VALVE
DRIER
VALVE
EQUALIZER
CAPILLARY
EVAPORATOR
EXPANSION
A- A
VALVE
ISOLATION SIGHT
FILTER
ISOLATION
VALVE GLASS
DRIER
VALVE
EQUALIZER
CAPILLARY
EVAPORATOR
EXPANSION
A- A
VALVE
SIGHT
ISOLATION FILTER
ISOLATION
GLASS
VALVE DRIER
VALVE
EQUALIZER
CAPILLARY
EVAPORATOR
EXPANSION
A- A
VALVE
CONDENSER
WATER
BYPASS WATER SENSORS
OUT
VALVE
CONDENSER
WATER
MODERATING
IN
VALVE
SUCTION
LINE
CAPILLARY
EXPANSION
VALVE
BULB
30°
SECTION A - A
43