EarthLinked SCWD-024-1C, Quick Start Instructions

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SCWD-QS (12/16) Page 44
4) Final Charge
1. Remove the Schrader core tool from the hose just taken off of the initial charging port.
2. Crack open the LP valve on the manifold gauge set so that a small amount of refrigerant gas
flows to purge the hose. Connect the hose to the final charging port, shown in Figure 27.
Tighten the hose to the final charging port and turn off the LP valve when the hose connection
is secure.
3. Start the system in heat mode.
Disconnect the control wire from the “O” terminal to ensure
the system remains in the heat mode during the final charging process. In an air system, the
design (and minimum) air flow is 400 cfm per nominal ton. In a hydronic system, the design
(and minimum) circulating water flow to 3 gpm per nominal ton. As installed, higher than
design air and circulating water flows are acceptable, recognizing that this will cause greater
power consumption by the air handler and circulating pump motors.
4. Slowly open the LP valve on the manifold gauge set and add refrigerant just fast enough to
maintain the suction pressure.
5. While still weighing the refrigerant, slowly add refrigerant until liquid refrigerant is clearly seen
in the middle sight glass of the ACC, as shown in Figure 28.
6. Shut the LP valve on the manifold gauge set and run the system for 20 minutes to ensure that
the refrigerant liquid level remains at the middle slightly glass. If the liquid refrigerant level
drops below the middle sight glass during this time, slowly add refrigerant until the liquid level
stabilizes at the middle sight glass.
7. With the liquid refrigerant level at the middle sight glass, attach and insulate a temperature
clamp or probe securely to the earth loop vapor line at the compressor unit service valve
shown in Figure 27. Read the measured temperature. Also read the LP gauge pressure on the
manifold gauge set. Use a pressure/temperature chart (Figure 30) to verify that the system is
operating at saturation, meaning that no superheat is measured on the earth loop vapor line.
To verify this, the measured vapor line temperature should be within ± 3°F of the saturation
temperature read from the chart for the measured LP gauge pressure. If the measured
temperature is out of this range, contact ETI technical support at 1/863-701-0096.
8. After verifying that the system is operating at saturation in heating mode, and with the
system still operating in heating mode, slowly open the LP valve on the manifold gauge
set, and slowly add refrigerant to the system until the refrigerant liquid level is at, but not
above, the top ACC sight glass, as shown in Figure 29. At no time should the refrigerant
liquid level be above the top ACC sight glass.
9. The system is now fully charged. Document the weight of the total refrigerant charge in
the system.
Write it down on the Warranty Registration Card and inside the compressor
unit on the electrical diagram, for future reference.
10. Re-
connect the control wire to the “O” terminal. The system is now operational in heating and
cooling modes.