Geothermal: Cooling

Re: Cooling Equipment Operating Conditions

Climatemaster produces a very detailed chart that shows accurate temperatures and refrigerant pressures for different operating conditions.

In order to use this chart, the technician must retrieve and record the following operating data and report to supervisor or check IOM paperwork.

1. Check Loop Water

• Pumps
• Use an Amp Probe to check amperage on each loop pump to ensure that they are operating.
  • Pumps should start with the compressor.
  • Each pump should draw .7 to .8 amps.
• Pressure Drop
• Use a Pressure Gauge to check the water pressure drop through the unit.
  • Use performance chart to calculate and record the GPM/Ton.
    • No Pressure or Negative Pressure = Low Water
• Temperature Rise
• Use a thermometer to check the water temperature rise across the unit while the compressor is operating at full capacity.
  • Check and record the inlet water temperature.
  • Check the outlet water temperature.
    • Calculate and record the water temperature rise.

2. Check Refrigerant Pressures

• Hook-up refrigerant gauges to the pressure ports on the unit.
  • Blue --> "True Suction" Low Pressure
  • Red --> High Pressure
• Place an insulated temperature sensor on the liquid line between the evaporator coil and expansion valve.
• Monitor and record the pressures as the system operates.
• Calculate and record the "Sub-Cooling".
  • Check "Saturation Temperature" from the discharge pressure gauge.
  • Subtract the Actual liquid line temperature reading.
    • Saturation Temp - Liquid Line Temp = Sub-Cooling

• (Split-Systems) If a Liquid-Line Sight Glass is installed, observe for bubbles in the sight glass in-lieu of checking sub-cooling (after the system has been operating for at least 5 min.)

3. Check Air Temperature Drop

• Check the Return Air Temperature near the unit or in the filter compartment.
• Check the Supply Air Temperature.
• Calculate and record the air temperature drop.