Product Manual PM WSC/WDC 31
Compressor
Compressor Weights
Compressor Size ⇒ 050 063 079 087 100 126
Weight lb (kg) ⇒ 870 (390) 3200 (1440) 3200 (1440) 3200 (1440) 6000 (2700) 6000 (2700)
Relief Valves
Vessel Relief Valves
Relief valve connection sizes and quantity
are shown to the right. Relief valves must
be piped to the outside of the building in
accordance with ANSI/ASHRAE 15. Twin
relief valves mounted on a transfer valve are
used on the condenser so that one relief
valve can be shut off and removed leaving
the other in operation. Where 4 valves are
shown, they consist of two valves mounted
on two transfer valves. Only two relief valves of the four are active at any time.
Vent piping is sized for only one valve of the set since only one can be in operation at a time. In no case would
a combination of evaporator and condenser sizes require more refrigerant than the pumpdown capacity of the
condenser. Condenser pumpdown capacities are based upon ANSI/ASHRAE Standard 15-1992
recommendations of 90% full at 90°F (32°C). To convert values to the older ARI standard, multiply pumpdown
capacity by 0.888.
Relief Valve Pipe Sizing
Relief valve pipe sizing is based on the discharge capacity for the given evaporator or condenser and the length
of piping to be run. Discharge capacity for HFC-134a vessels is calculated as follows:
C xDxL= 0 133.
Where: C=Minimum discharge capacity, lbs of air/min
D=Vessel diameter, in.
L=Vessel length, ft.
Example: E3016 Evaporator, HFC-134a Refrigerant, 75 equivalent feet of piping
C x x Lbs of air= =0133 30 16 63 8. . / min
From the table below, 75 feet of piping for 63.8 lb. of air/min. at 180 psig valve setting requires a 2" diameter pipe.
Discharge Capacity, lbs of Air/Min
EQUIVALENT DIAMETER STANDARD WALL IRON PIPE
LENGTH OF 1” (25mm) 1.25” (32mm) 1.5” (38mm) 2” (50mm) 2.5” (64mm) 3” (76mm)
DISCHARGE RELIEF VALVE PRESSURE SETTNG
PIPING, FT. (m) 180 225 180 225 180 225 180 225 180 225 180 225
50 (15.2) 21.4 26.8 42.8 53.6 62.7 78.4 117.0 146.3 182.2 227.7 315.4 393.7
75 (22.9) 17.5 21.9 35.0 43.8 51.5 64.4 95.4 119.3 150.5 188.1 257.4 321.8
100 (30.5) 15.2 19.1 30.2 27.8 44.3 55.4 82.6 103.3 129.6 162.0 222.5 278.1
150 (45.7) 12.4 15.6 24.7 30.9 36.0 45.0 67.3 84.2 105.1 131.9 182.2 227.7
200 (61.0) 10.6 13.6 21.4 26.8 31.4 39.3 58.4 73.1 91.1 113.9 157.7 197.1
300 (91.4) 8.8 11.1 17.5 21.9 25.5 32.0 47.6 59.6 75.6 94.5 128.5 160.7
Note: Standard relief valve settings; R-134a, evaporator=180 psig, condenser=225 psig
Note: Per ASHRAE Standard 15, the pipe size may not be less than the relief device, meaning a minimum 1"
diameter pipe is required. The discharge from more than one relief valve may be run into a common header, the
area of which shall not be less than the sum of the areas of the connected pipes. For further details, refer to
ASHRAE Standard 15. The common header can be calculated by the formula:
Relief Valve
Evaporator Code
Connection Number
E1608 Thru E2616 1” FPT 1
E3016 Thru E4216 1” FPT 1
E4816 Thru E4824 1” FPT 2
Condenser Code
C1608 thru C3016 1” FPT 2
C3616 Thru C4216 1” FPT 2
C4816 Thru C4824 1” FPT 4
To Next Page
Loading...
Need help?
General
