GPH16M Installation Manual

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4. If the outdoor ambient is above 80°F, the unit may trip on its high pressure cut out when on heating. The compressor should
stop. The heating cycle must be thoroughly checked, so postpone the test to another day when conditions are more suitable.
DO NOT FAIL TO TEST.
5. If the outdoor ambient is low and the unit operates properly on the heating cycle, you may check the pressure cutout operation
by blocking off the indoor return air until the unit trips.
6. If unit operates properly in the heating cycle, raise the temperature setting until the heating second stage makes contact.
Supplemental resistance heat, if installed should now come on. Ensure all heaters energize.
NOTE: All 16 SEER models have two stages of compressor heat. During resistance heat test, increase temperature setting
until third stage heat is energized.
If outdoor thermostats are installed, the outdoor ambient must be below the set point of these thermostats for the heaters to
operate. It may be necessary to jumper these thermostats to check heater operation if outdoor ambient is mild.
7. THERMOSTATS WITH EMERGENCY HEAT. For thermostats with an emergency heat switch, raise the temperature setting until
the heating second stage makes contact. The emergency heat switch is located at the bottom of the thermostat. Move the switch
to emergency heat. The heat pump will stop, the blower will continue to run, all heaters will come on and the thermostat
emergency heat light will come on.
8. If checking the unit in the wintertime, when the outdoor coil is cold enough to actuate the defrost control, observe at least one
defrost cycle to make sure the unit defrosts completely.
FINAL SYSTEM CHECKS
1. Ensure all supply and return air grilles are adjusted and the air distribution system is balanced for the best compromise
between heating and cooling.
2. Ensure there are no air leaks in the duct work.
3. Check air flow and refrigerant charge. See Sections on Air Flow Measurement and Adjustment and Checking Charge.
4. Ensure the unit is free of “rattles”, and the tubing in the unit is free from excessive vibration. The tubes or lines should not rub
against sheet metal surfaces, edges or each other.
5. Ensure the Owner is instructed on the unit operation, filter, servicing, correct thermostat operation, etc.
Set the thermostat at the appropriate setting for cooling and heating or automatic changeover for normal use.
NOTE: The “Cooling Start-up Procedure” is a recommended step as it serves as an system indicator that the unit will operate
normally.
COMPONENTS
Contactor
This control is activated (closed) by the room thermostat for both heating and cooling. The contactor has a 24V coil and supplies
power to the compressor and outdoor fan motor.
Crankcase Heater
This item is “ON” whenever power is supplied to the unit and the crankcase heater thermostat is closed. Crankcase heater
thermostat closes at 67° and opens at 85°. It warms the compressor crankcase thereby preventing liquid migration and subsequent
compressor damage. The insert type heater is self regulating. It is connected electrically to the contactor L1 and L2 terminals.
Condenser Motor
This item is activated by the contactor during heating and cooling, except during defrost and emergency heat operation. On 460V
heat pumps, the condenser motor is activated by the CMR.
Compressor
This item is activated by the contactor for heating and cooling, except during emergency heat. It is protected by an internal overload.
Contactor Relay
This control is activated by the thermostat (24V coil) and supplies power to the contactor.
Defrost Control
The Defrost Control provides time/temperature initiation and termination of the defrost cycle. When a defrost cycle is initiated, the
Defrost Control shifts the reversing valve to “COOLING” mode, stops the outdoor fan and brings on supplemental heat. Normally,
a defrost cycle will take only 2-3 minutes unless system is low on refrigerant charge or outdoor conditions are severe (i.e. windy
and cold). The defrost control also provides for a 3 minute off cycle compressor delay.
Outdoor Thermostat
These optional controls are used to prevent full electric heater operation at varying outdoor ambient (0°F to 45°F). They are normally
open above their set points and closed below to permit staging of indoor supplement heater operation. If the outdoor ambient
temperature is below 0°F (-18°C) with 50% or higher RH, an outdoor thermostat (OT) must be installed and set at (0°) on the dial.
Failure to comply with this requirement may result in damage to the product which may not be covered by the manufacturer’s
warranty.