Daikin RoofPak RPS Series Installation And Maintenance Manual page 41

Charging the System
Adding refrigerant to the suction always risks liquid-related
damage to the compressor.
Units purchased for R-22 operation must be charged only with
R-22. Units purchased for R-407C operation must be charged
only with R-407C. Field mixing or changing of refrigerants can
compromise performance and damage equipment.
RCS units are leak tested at the factory and shipped with a
nitrogen holding charge. If the holding charge has been lost
due to shipping damage, charge the system with enough
refrigerant to raise the unit pressure to 30 psig after first
repairing the leaks and evacuating the system.
1. After all refrigerant piping is complete and the system
is evacuated, it can be charged as described in the
paragraphs following. Connect the refrigerant drum to
the gauge port on the liquid shutoff valve and purge the
charging line between the refrigerant cylinder and the
valve. Then open the valve to the mid position.
2. If the system is under a vacuum, stand the refrigerant
drum with the connection up, open the drum, and break
the vacuum with refrigerant gas.
3. With a system gas pressure higher than the equivalent
of a freezing temperature, invert the charging cylinder
and elevate the drum above the condenser. With
the drum in this position and the valves open, liquid
refrigerant flows into the condenser. Approximately 75%
of the total requirement estimated for the unit can be
charged in this manner.
4. Refrigerant charging with Zeotropes—R-407C is a
zeotropic mixture (see
113). During initial charging or "topping" off a system, 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.
5. After 75% of the required charge enters the condenser,
reconnect the refrigerant drum and charging line to the
suction side of the system. Again, purge the connecting
line, stand the drum with the connection side up, and
place the service valve in the open position.
NOTE: Stamp the total operating charge per circuit on the
unit nameplate for future reference.
Take special care to add refrigerant slowly enough to
the suction to prevent damage. Adjust the charging tank
hand valve so liquid leaves the tank but vapor enters the
compressor.
www.DaikinApplied.com
CAUTION
CAUTION
Refrigerant Charge on page
This is especially true with R-407C because the charge must
be drawn from the liquid portion of the tank.
Table 17: Acceptable Refrigerant Oils
ICI EMKARATE RL
NOTE: Do not use mineral oils
Refrigerant Charge
Each unit is designed for use with R-22 or R-407C. The total
charge per circuit is the sum of the following four values:
• Condenser section charge, see
• Evaporator coil charge, see
• Charge for length of unit piping to the evaporator coil, see
Table 11.
• Charge for length of interconnecting piping between the
RCS and RFS units, installed by field, see
page 40
The exact charge for a one piece RPS/RDT is on the unit
nameplate.
NOTE: The total operating charge per circuit should not
exceed the pumpdown capacity per circuit shown in
Table 11 through
Subcooling
When field charging the unit, use the following to properly
charge the unit:
• All compressors on each circuit operating at full capacity.
• Allowable subcooling ranges are between 13°F to 20°F.
• Be sure to measure pressure and temperature at the
same location when finding/calculating subcooling.
Compare the actual temperature and pressures to
the saturated liquid temperature. R-407C example: A
pressure of 250 psi is measured at the condenser outlet.
From the R-407C chart, 250 psig is approximately 108°F
saturated liquid temperature. If the actual refrigerant
temperature is 98°F, the liquid is subcooled 10°F.
• Ambient temperature must be between 60°F and 105°F.
• Hot Gas Bypass NOT operating (only if unit is supplied
with option).
• SpeedTrol motors operating at 100% (only if unit is
supplied with option).
If any one of the above items is not followed, subcooling
readings will not be accurate and the potential exists for over
or undercharging of the refrigerant circuit.
41 IM 926-3 • ROOFPAK APPLIED SYSTEMS
Mechanical Installation
Polyolester [POE] oils
Copeland ULtra 22 CC
Mobil EAL Arctic 22 CC
™
32CL
™
Table 11 on page
Table 11.
Table 15 on
Table 15.
39.