Carrier PTACSTAT-NP-HP Installation & Operating Manual page 13

Meanings:
PC or PH selects PTAC units (Packaged Terminal Air Conditioners).
PH controls a PTAC with 1 speed heat pump with 1 stage of aux heat.
PC controls a PTAC with 1 speed air conditioner with 1 stage of E1 heat.
NOTE: A PH thermostat can be converted to control a HeatCool system.
Option 03 - - Fahrenheit/Centigrade
Selects temperature measurement units.
Selections:
F = Fahrenheit
C = Centigrade
Default is Fahrenheit
Option 04 - - Not used on a PTAC system
Default = OF
Option 07 - - Not used on a PTAC system
Default = OF
Option 10 - - Reversing valve (HP only)
This selection is only available on heat pump systems. "O/B" terminal can be
configured to be energized in either heating mode or in cooling mode, depending
on heat pump operation.
C — Thermostat output (O/B) will have 24VAC in cooling mode, 0VAC in
heating mode.
H — Thermostat output (O/B) will have 0VAC in cooling mode, 24VAC in
heating mode.
Default is C for PTAC.
13