Puronr (R−410A) Refrigerant - Carrier 50TC*17 Series Service And Maintenance Instructions

PURONR (R−410A) REFRIGERANT
This unit is designed for use with PuronR (R−410A)
refrigerant. Do not use any other refrigerant in this
system.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this CAUTION can result in damage to
components.
The compressor is in a PuronR (R−410A) refrigerant
system and uses a polyester (POE) oil. This oil is
extremely hygroscopic, meaning it absorbs water
readily. POE oils can absorb 15 times as much water as
other oils designed for HCFC and CFC refrigerants.
Avoid exposure of POE oil to the atmosphere. Exposure
to the atmosphere can cause contaminants that are
harmful to R−410A components to form. Keep POE oil
containers closed until ready for use.
PuronR (R−410A) refrigerant is provided in pink (rose)
colored cylinders. These cylinders are available with and
without dip tubes; cylinders with dip tubes will have a
label indicating this feature. For a cylinder with a dip
tube, place the cylinder in the upright position (access
valve at the top) when removing liquid refrigerant for
charging. For a cylinder without a dip tube, invert the
cylinder, with theaccess valve located on the bottom,
when adding liquid refrigerant.
Because PuronR (R−410A) refrigerant is a blend, it is
strongly recommended that refrigerant always be removed
from the cylinder as a liquid. Admit liquid refrigerant into
the system in the discharge line when breaking the
refrigerant system vacuum while the compresor is OFF.
Only add refrigerant (liquid) into the suction line while
the compressor is operating. If adding refrigerant into the
suction line, use a commercial metering/expansion device
at the gauge manifold; remove liquid from the cylinder,
pass it through the metering device at the gauge set, and
then pass it into the suction line as a vapor. Do not remove
PuronR (R−410A) refrigerant from the cylinder as a
vapor.
Refrigerant Charge
Unit panels must be in place when the unit is operating
during the charging procedure. To prepare the unit for
charge adjustment:
No Charge
Use standard evacuating techniques. Evacuate the system
down to 500 microns and let set for 10 minutes to
determine if the system has a refrigerant leak. If the
evacuation level raises to 1100 microns and stabilizes,
then the system has moisture in it and should be
dehydrated as GTAC2-5 recommends.
If the system continues to rise above 1100 microns, then
the system has a leak and should be pressurized and leak
tested using appropriate techniques as explained in
GTAC2-5. After evacuating the system, weigh in the
specified amount of refrigerant as listed on the unit's
rating plate.
Low−Charge Cooling
Using the Cooling Charging Charts (Figs. 23 thru 30),
vary the refrigerant until the conditions of the appropriate
chart are met. Note the charging charts are different from
the type normally used. These charts are based on
charging the units to the correct superheat for the various
operating conditions. Accurate pressure gauge and
temperature sensing devices are required. Connect the
pressure gauge to the service port on the suction line.
Mount the temperature sensing device on the suction line
and insulate it so the outdoor ambient temperature does
not affect the reading. Indoor-air cfm must be within the
normal operating range of the unit.
SIZE DESIGNATION
17
20
24
28
EXAMPLE:
Model 50TC*D28
Circuit A
Outdoor Temperature . . . . . . . . . . . . . . . . . .
Suction Pressure . . . . . . . . . . . . . . . . .
Suction Temperature should be
Circuit B
Outdoor Temperature . . . . . . . . . . . . . . . . . .
Suction Pressure . . . . . . . . . . . . . . . . .
Suction Temperature should be
Using the Cooling Charging Charts
Take the outdoor ambient temperature and read the
suction pressure gauge. Refer to the chart to determine
what the suction temperature should be. If the suction
temperature is high, add refrigerant.
If the suction temperature is low, carefully recover some
of the charge. Recheck the suction pressure as the charge
is adjusted.
Select the appropriate unit charging chart from Figs. 22
thru 29.
Note the outdoor ambient temperature and read the
suction pressure gauge. Refer to the chart to determine
what the suction temperature should be. If the suction
temperature is high, add refrigerant. If the suction
temperature is low, carefully recover some of the charge.
Recheck the suction pressure as the charge is adjusted.
For 17–28 sizes, perform this procedure once for Circuit
A (using the Circuit A chart) and once for Circuit B (using
the Circuit B chart).
19
NOMINAL TON REFERENCE
15
17.5
20
25
85_F (29_C)
125 psig (860 kPa)
. . . . . . . . . . 63_F (17_C)
85_F (29_C)
120 psig (830 kPa)
. . . . . . . . . . 58_F (14_C)