Carrier GT-G User Manual

Also see for GT-PX: Technical guide

Contents

CarrierCarrier Indoor & Outdoor Split Geothermal Heat Pumps - Rev.: 08/10/0548Air Handler Selection ExampleFigure 1 shows a typical peformance table for a heatpump air handler. Suppose the evaporator temperaturerequired is 50ºF, the capacity required is 35,000 Btuhand the airflow required is 1,200 CFM. Each evaporatortemperature listed in the table shows three wet bulbtemperatures. As recommended in the table notesabove, select the 67ºF WB column. At 1,200 CFM, themodel 003 capacity is 36 MBtuh, which is higher thanthe minimum capacity required of 35,000 Btuh. In thisexample, model 003 would be the appropriate match.Figure 1: Selecting Air HandlerUtilizing the Existing Air Handler or Coil (R22 units only)It is recommended that a new coil or air handler beinstalled with any geothermal split system compressorsection due to the low initial cost of the additionalequipment versus the reliability and benefit of newtechnology, increased reliability and warranty. However, ifthe existing air handler must be used (R22 systems only),the following conditions apply:• If the existing coil currently uses an orifice, the orificemust be removed and replaced with a TXV. If the coilutilizes capillary tubes, it will not operate properly withthe geothermal split system and should be replaced.• If life expectancy of indoor coil (and associatedcomponents - fan, cabinet, etc.) is less than 7-10 years,indoor section should be replaced.Equipment SelectionSelecting Air Handler