Specifications

GT-PCS Split Units - 60Hz Puron
®
Created: 29 Aug., 2013
28
 NOTICE! 
NOTICE: Use tables 16a to 16d for superheat/
subcooling values. These tables use discharge pressure
(converted to saturation temperature) and liquid line
temperature for subcooling calculations. If using liquid
line pressure, subtract 3°F from the table values.
Evacuation Of The Lineset And Coil
The line set and coil must be evacuated to at least 500
microns to remove any moisture and noncondensables.
Evacuate the system through both service ports in the
shipping position (full CW in - see table 8) to prevent false
readings on the gauge because of pressure drop through
service ports. A vacuum gauge or thermistor capable of
accurately meausuring the vacuum depth is crucial in
determining if the system is ready for charging. If the system
meets the requirements in Figure 17, it is ready for charging.
Figure 17: Evacuation Graph
Charging The System
There are two methods of charging a refrigerant system. One
method is the total charge method, where the volume of the
system is determined and the refrigerant is measured and
added into the evacuated system. The other method is the
partial charge method where a small initial charge is added
to an evacuated system, and remaining refrigerant added
during operation.
Total Charge Method - See Table 7 for the compressor
section basic charge. For line sets with 3/8” liquid lines
add 0.6 ounces of refrigerant to the basic charge for every
installed foot of liquid line [0.6 grams per cm]. Add 1.2 oz.
per foot [1.1 grams per cm] if using l/2” line. Once the total
charge is determined, the factory pre-charge (Table 7) is
subtracted and the remainder is the amount needed to be
added to the system. This method should be used with the
AHRI matched air handler.
Refrigeration Installation
Determining Superheat:
1. Measure the temperature of the suction line at a point
near the expansion valve bulb.
2. Determine the suction pressure by attaching refrigeration
gauges to the suction schrader connection at the
compressor.
3. Convert the pressure obtained in step 2 to saturation
temperature (boiling point) by using the pressure/
temperature conversion table on the gauge set.
4. Subtract the temperature obtained in step 3 from step
1. The difference will be the superheat of the unit or the
total number of degrees above saturation temperature.
Refer to Tables 16a-16d for superheat ranges at specifi c
entering water conditions.
Example:
The temperature of the suction line at the sensing bulb is
50°F. The suction pressure at the compressor is 110 psig
which is equivalent to 36°F saturation temperature from the
Puron
®
press/temp conversion table on the gauge set.
36°F subtracted from 50°F = 14°F Superheat.
Determining Sub-Cooling:
1. Measure the temperature of the liquid line on the smaller
refrigerant line (liquid line) just outside of the cabinet.
This location will be adequate for measurement in both
modes unless a signifi cant temperature drop in the liquid
line is anticipated.
2. Determine the condensor pressure (high side) by
attaching refrigerant gauges to the schrader connection
on the liquid line service valve. If the hot gas discharge
line of the compressor is used, refer to the appropriate
column in Tables 16a-16d.
3. Convert the pressure obtained in step 2 to the
saturation temperature by using the press/temp
conversion table on the gauge set.
4. Subtract the temperature of Step 3 from the temperature
of Step 1. The difference will be the sub-cooling value for
that unit (total degrees below the saturation temperature).
Refer to Tables 16a-16d for sub-cooling values at specifi c
entering water temperatures.
Example:
The condenser pressure at the service port is 335 psig,
which is equivalent to 104°F saturation temperature.
Discharge pressure is 365 psig at the compressor (109°F
saturation temperature). Measured liquid line temperature is
100°F. 100°F subtracted from 104°F = 4 degrees sub-cooling
(9 degrees if using the compressor discharge pressure).