Refrigerant Charge - Daikin Maverick II MPS062E Installation And Maintenance Manual

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
refrigerant circuit in case a full charge must be added to the
unit. Verify these values using pages
The micro-channel condenser requires much lesscharge than
traditional fin tube condensers. This means there is 35% less
charge to recover when servicing the refrigeration circuit, but
the condenser will not hold a high percentage of the charge.
The impact on service is as follows:
• Positive impact – the replacement refrigerant portion of
service cost will be less
• Positive impact – it takes less time to reclaim the entire
charge or the high side portion of the system.
• Negative impact – it takes more time to reclaim the
low side portion of the system because you cannot first
pumpdown most to the high side.
The micro-channel condenser coil design does not contain
the internal volume to support the pumpdown of the entire
unit charge into the condenser coil. To aid in the removal of
refrigerant from the system, a Shrader valve port with a core has
been provided on the liquid line, ahead of the liquid line shut-
off valve. The port is intended for connecting to a suitable (and
approved) storage container while using the unit compressor(s)
to pump liquid refrigerant into a storage container.
IM 991-2 • MAVERICK II ROOFTOP
WARNING
Table 7 on page 95.
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. Units with Fantrol, setpoint =
70 psig. Units with Speedtrol, setpoint = 25 psig
(low ambient).
b. Enables their associated compressors on a rise in
suction pressure. Units with Fantrol, setpoint = 120
psig. Units with Speedtrol, setpoint = 60 psig.
2. High refrigerant pressure, protective switch, manual
reset, reset by breaking control power to the S1 control
switch.
a. All R-410A high pressure switches disable their
associated compressors on a rise in discharge
pressure to 650 psig.
b. The switches have a differential of 150 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.
102
Maintenance
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