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Refrigerant Charge
Potential severe loss of charge may occur if the high refrigerant
pressure switch is replaced before reclaiming the refrigerant.
Replace switch after reclaiming refrigerant.
The unit nameplate references proper charge for each RPS/
RDT refrigerant circuit in case a full charge must be added to
the unit. Verify these values using the tables on
through
page
40. Also refer to the tables on
through
page 40
for RFS/RCS units.
Servicing Refrigerant Sensors or Switches
The Daikin Rooftop unit includes the following refrigerant
sensors or switches.
1. Low refrigerant pressure sensing, operating switch,
automatic reset.
a. Disables their associated compressors on a drop in
suction pressure to approximately 35 psig.
b. Enables their associated compressors on a rise in
suction pressure to approximately 60 psig.
2. SpeedTrol
high refrigerant pressure sensor (not
™
available on sizes 15 to 30), see
information.
3. High refrigerant pressure, protective switch, manual reset,
reset by breaking control power to the S1 control switch.
a. R-407C high pressure switches disable their
associated compressors on a rise to 425 psig
discharge pressure.
b. The switches have a differential of 100 psig.
The low pressure and SpeedTrol sensors/ switches sense
refrigerant pressure through shrader fittings that contain cores.
The cores are stop valves that do not allow refrigerant to flow
through the shrader unless the device is in place. Therefore the
low pressure and SpeedTrol sensors/switches can be replaced
without reclaiming the refrigerant.
The Shrader that serves the high pressure switch does
not contain a core in order to maximize the functionality
of the safety . Therefore it cannot be replaced unless the
refrigerant has already been reclaimed .
www.DaikinApplied.com
WARNING
page 39
page 39
page 85
for more
Refrigerant Leaks
R-407C is a zeotropic blend of three HFC refrigerants (R-32,
R-125, and R-134a). 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 an 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 leaked. However, experience in the field has
shown that R-407C systems can be "topped off" after a leak
and will operate normally . There is no need, except in the
case of critically charged systems, to replace the entire charge
after a leak. Add charge per instructions on
113
IM 926-3 • ROOFPAK APPLIED SYSTEMS
Maintenance and Service
page
41.
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