EarthLinked SC Series, Quick Start Instructions

Page: 33 / 35

SC-410-QS (05/11) Page 33
Cooling Assist Valve (CAV) Adjustment
After the system has been fully charged, the Cooling Assist Valve (CAV) is to be adjusted in
accordance with the following instructions or the process flow chart in Figure 30.
1. Before adjusting the CAV, attach a thermocouple lead with electrical tape, then
wrapped with ½” thick insulation, to the liquid refrigerant line between the compressor
unit and the air handler (or between the compressor unit and the hydronic heat
exchanger) as shown in Figure 27. Use an accurate temperature indicator.
2. Run the air handler and compressor unit system in cooling mode with return air
temperature maintained at 70°F. If necessary, warm the return air with the electric
strip heat in the air handler. For chilled water systems, water return temperature
should be maintained at 45
o
F to 50
o
F.
3. The CAV has been adjusted to full open position at the factory. This is the extreme
counterclockwise position.
4. After an initial drop in suction temperature (when the system is first started in cooling
mode) the suction temperature will begin to rise, as will the liquid refrigerant level in
the ACC.
5. When suction temperature climbs to greater than 35°F, adjust the cooling assist valve
(CAV) slowly CLOCKWISE – 1/4 turn is typical. Do not allow the suction temperature
to drop below 35°F. Observe the refrigerant quality in the in-line sight glass
immediately upstream of the CAV, shown in Figure 27.
Figure 27. Refrigerant Flow During CAV Adjustment.