Installation Guide for NHPA Split-System Heat Pumps
11
Installers Notes:
• Condenser door must be in place while adjusting subcooling
• Ambient temperature must be between 65
�
F-95
�
F
• Indoor return air temperature must be above 70
�
F
• Allow 10 to 20 minutes of run time at premium conditions
before adjusting charge
• Driving rain against the condenser coil can affect setting proper
subcooling
• Add charge to increase subcooling
• Remove charge to decrease subcooling
• Indoor units must be equipped with a thermal expansion valve
(TXV)
in the pan. The condensate pan under the coil must be piped
per item number 12 under the “Unit Location Considerations”
section of this manual.
System Charge Adjustment
Temperature Measurements
Check the outdoor temperatures. Subcooling (in cooling mode) is
the only recommended method of charging above 55º F ambient
outdoor temperature. For best results the indoor temperature
should be kept between 70º F to 80º F.
Note:
It is important to return in the spring or summer to
accurately charge the system in the cooling mode when outdoor
ambient temperature is above 55º F.
Stabilize the system by operating for a minimum of 20 minutes.
At startup, or whenever charge is removed or added, the system
must be operated for a minimum of 20 minutes to stabilize
before accurate measurements can be made.
