![background image](http://html1.mh-extra.com/html/york/ycul0045/ycul0045_installation-operation-and-maintenance_4223634018.webp)
JOHNSON CONTROLS
18
FORM 150.63-NM6 (1020)
Evaporator Below Condensing Unit
On a system where the evaporator is located below the
condensing unit, the suction line must be sized for both
pressure drop and oil return. In many cases a double
suction riser must be installed to ensure reliable oil
return at reduced loads. Table 5 & 6 indicates when
a double suction riser should be used for listed pipe
sizes to provide adequate oil return at reduced loads.
The calculated information was based on maintaining
a minimum of 1000 fpm (5.08 m/s) refrigerant vapor
velocity at full load.
Condenser Below Evaporator
When the condensing unit is located below the evapo-
rator, the liquid line must be designed for both friction
loss and static head loss due the vertical rise. The value
of static head loss of 5 psi/ft.(3.4 kPa/30 cm) must be
added to the friction loss pressure drop in addition to
all pressure drops due to driers, valves, etc.
OIL TRAPS
All horizontal suction lines should be pitched at least
1/4" per foot (2 cm/m) in the direction of the refrigerant
flow to aid in the return of oil to the compressor. All
suction lines with a vertical rise exceeding 3 feet (.91
meters) should have a “P” trap at the bottom and top
of the riser to facilitate oil return. Suction lines with a
vertical rise exceeding 25 feet (7.6 meters) should be
trapped every 15 feet (4.6 meters).
For more details, refer to ASHRAE Refrigeration Hand-
book. System Practices for Halocarbon Refrigerants.
On systems where oil return is a prob-
lem, oil separators may be required.
However, if piping design is poor, even
with a separator, oil may be lost into
the system over time, which may cause
compressor failure.
REFRIGERANT CHARGE
The condensing unit is charged with nitrogen a hold-
ing charge. The operating charge for the condensing
unit, evaporator coil, and refrigerant piping must be
“weighed-in” after all refrigerant piping is installed,
leak checked, and evacuated.
70% of the calculated charge must
be added prior to starting a system .
Failure to add 70% of the charge may
cuase compressor overheating when
the system is first started.
Final adjustment of refrigerant charge should be verified
by subcooling values (refer to section on Pre-Startup
for checking subcooling). See Table 3 for Refrigerant
Line Charges.
FILTER DRIERS/ SIGHT GLASSES/ TXV'S
Liquid line filter driers, sight glass, and TXV's are field
supplied for each refrigerant circuit.
REFRIGERANT PIPING REFERENCE
For more details, refer to ASHRAE Refrigeration Hand-
book, Chapter 2.
Installation
TABLE 1
– FITTING EQUIVALENT LENGTHS
*COPPER FITTING EQUIVALENT LENGTHS
LINE SIZE O.D.
SHORT-RADIUS ELL
LONG-RADIUS ELL
3/4" (19mm)
6.5 ft. (2m)
4.5 ft. (1.4m)
7/8" (22mm)
7.8 ft. (2.4m)
5.3 ft. (1.6m)
1-1/8" (29mm)
2.7 ft. (.8m)
1.9 ft. (.6m)
1-3/8" (35mm)
3.2 ft. (1m)
2.2 ft. (.7m)
1-5/8" (41mm)
3.8 ft. (1.2m)
2.6 ft. (8m)
2-1/8" (54mm)
5.2 ft. (1.6m)
3.4 ft. (1m)
2-5/8" (67mm)
6.5 ft. (20m)
4.2 ft. (1.3m)
TABLE 2
– MISCELLANEOUS LIQUID LINE
PRESSURE DROPS
*MISCELLANEOUS LIQUID LINE PRESSURE
SOLENOID VALVE
2 TO 3 PSI (13.8 TO 20.7 kPa)
FILTER/DRIER
2 TO 3 PSI (13.8 TO 20.7 kPa)
SIGHT GLASS
0.5 PSI (3.4 kPa)
TABLE 3
– REFRIGERANT PIPING CHARGES
REFRIGERANT LINE CHARGES
SUCTION LINES
LIQUID LINES
1-3/8" (35mm)
.2 oz./ft. (6 grams/30cm)
3/4" (19mm)
2.7 oz./ft. (76 grams/30cm)
1-5/8" (41mm)
.3 oz./ft. (8 grams/30 cm)
7/8" (22mm)
3.7 oz./ft. (105 grams/30cm)
2-1/8" (54mm)
.6 oz/ft. (17 grams/30cm)
1-1/8" (29mm)
6.2 oz./ft. (176 grams/30cm)
2-5/8" (67mm)
.8 oz./ft. (23 grams/30cm)
1-3/8" (35mm)
8.6 oz./ft. (244 grams/30cm)
* Pressure drops or equivalent length values are approximate. If more precise value is desired, consult either the York DX Piping Guide (form
050.40-ES2) or ASHRAE Refrigerant Handbook.
* Pressure drops or equivalent length values are approximate.
If more precise value is desired, consult ASHRAE Refrigerant
Handbook.
Summary of Contents for YCUL0045
Page 13: ...JOHNSON CONTROLS 13 FORM 150 63 NM6 1020 This page intentionally left blank...
Page 31: ...JOHNSON CONTROLS 31 FORM 150 63 NM6 1020 1 This page intentionally left blank...
Page 35: ...JOHNSON CONTROLS 35 FORM 150 63 NM6 1020 1 This page intentionally left blank...
Page 71: ...JOHNSON CONTROLS 71 FORM 150 63 NM6 1020 1 This page intentionally left blank...
Page 79: ...JOHNSON CONTROLS 79 FORM 150 63 NM6 1020 This page intentionally left blank...
Page 117: ...JOHNSON CONTROLS 117 FORM 150 63 NM6 1020 2 This page intentionally left blank...
Page 120: ...JOHNSON CONTROLS 120 FORM 150 63 NM6 1020 Unit Controls THIS PAGE INTENTIONALLY BLANK...
Page 139: ...JOHNSON CONTROLS 139 FORM 150 63 NM6 1020 3 This page intentionally left blank...
Page 141: ...JOHNSON CONTROLS 141 FORM 150 63 NM6 1020 4 LD08801...
Page 145: ...JOHNSON CONTROLS 145 FORM 150 63 NM6 1020 4 LD08946...
Page 147: ...JOHNSON CONTROLS 147 FORM 150 63 NM6 1020 4 LD08800...
Page 151: ...JOHNSON CONTROLS 151 FORM 150 63 NM6 1020 4 LD08776...
Page 153: ...JOHNSON CONTROLS 153 FORM 150 63 NM6 1020 4 LD08804...
Page 155: ...JOHNSON CONTROLS 155 FORM 150 63 NM6 1020 4 LD08781...
Page 157: ...JOHNSON CONTROLS 157 FORM 150 63 NM6 1020 4 This page intentionally left blank...
Page 159: ...JOHNSON CONTROLS 159 FORM 150 63 NM6 1020 4 LD08803...
Page 161: ...JOHNSON CONTROLS 161 FORM 150 63 NM6 1020 4 LD08807...
Page 163: ...JOHNSON CONTROLS 163 FORM 150 63 NM6 1020 4 LD08785...
Page 165: ...JOHNSON CONTROLS 165 FORM 150 63 NM6 1020 4 This page intentionally left blank...
Page 167: ...JOHNSON CONTROLS 167 FORM 150 63 NM6 1020 4 LD08806...