Enertech Global, LLC

Split System Charging

Location of Install

Special care should be taken in locating the unit. All units should be placed on a vibration-absorbing pad (air pad) slightly bigger than the base of the unit. All units should be located in an indoor area were the ambient temperature will remain above 55°F. Piping of the unit should be installed in a configuration, which does not require piping to be removed during future service.

Installing the Line Set

The line set consists of brazed copper piping between the compressor section and the air coil section (see Table 1 for recommended line set sizes). On installations with a long line set, copper adapters may be needed to connect the larger diameter tubing to the service studs. A reversible heat pump filter drier must be installed on the liquid line near the compressor section. Line sets over 50 feet are not recommended because of oil transfer and pressure drop. The line set, especially the suction line, must always be insulated. If the tubing is accidentally kinked, bent, or flattened, the bad portion should be replaced by utilizing a coupling or swaging one end of the tubing.

Connecting the Air Coil:

Braze the line set by using a low silver-phosphorus-copper brazing (Dynaflow® or comparable) alloy on all connections. Nitrogen should always be bled through the system at 2-3 psi to prevent oxidation inside the tubing. Units are shipped with enough refrigerant for the compressor section and the matched air coil (or other brands with comparable face area sq. ft.).

Leak Testing:

The line set must be pressurized and leak checked before opening service valves on the compressor section. To check and pressure test the line, attach refrigerant gauges to both service ports, and add an inert gas (nitrogen or dry carbon dioxide) until pressure reaches 90-150 psig. Use a good quality bubble solution for the inert gas. If line set is tested and a leak is found, repair leak and repeat above steps.

Evacuating & Charging the System:

After purging the inert gas, the line set must be evacuated to at least 200 microns to remove air and moisture trapped in the line set and air coil. When the line set and air coil are purged and evacuated to 200 microns, and no leaks are found, the system is ready to be charged with refrigerant. Refrigerant can be added based on feet of liquid line. Refrigerant R-410A can be added as a liquid to the liquid line service port (Table 2 shows the weight of refrigerant per foot for typical liquid line sizes). Final charging of the unit should be checked by taking subcooling and superheat readings (see Table 3). The first subcooling reading can be done by opening the service valves and starting the unit in the cooling mode. If desired subcooling is not achieved, meter liquid refrigerant into the suction line in a manner, which allows the refrigerant to vaporize at the valve on the gauge set. Never add liquid refrigerant to the suction line of the compressor. After the system is charged properly, check performance and superheat. Superheat and subcooling should match Table 3. The unit must be checked in the heating mode, as well. Once the unit is started in the heating mode, superheat and subcool readings should match Table 3. If unit performs to specifications and superheat and subcooling is normal, the system is charged properly.

Performance Check:

Equipment should be in operation for a minimum of 10 minutes in either mode with the desuperheater pump turned off.

1. Determine flow rate in gallons per minute
   1. Check entering water temperature
   2. Check entering water pressure
   3. Check leaving water
2. Once this information is recorded, find corresponding entering water temperature column in Specification Manual for the model of the unit. Also locate pressure differential in PSI column. Then read the GPM column to determine flow in GPM.
3. Check leaving water temperature of unit.

Formula:

HE or HR (Heat of Extraction [Heating] or Heat of Rejection [Cooling]) = GPM X Water TD X 485(Antifreeze/water) or 500(fresh water)

A 10% variance from the Specification Manual is allowed. Water flow must be in range of the performance data. If system has too much or too little water flow, performance problems should be expected.

TABLE 2

TABLE 3

SPLIT SYSTEM REFRIG. CIRCUIT DIAGRAM

Attachments