Figure 12 - Horizontal Duct Cover Installation
DUCTWORK
Duct systems and register sizes must be properly designed for the C.F.M. and external static pressure rating of the unit. Ductwork should be designed in accordance with the recommended methods of Air Conditioning Contractors of America Manual D (Residential) or Manual Q (Commercial). All ductwork exposed to the outdoors must include a weatherproof barrier and adequate insulation.
A duct system should be installed in accordance with Standards of the National Board of Fire Underwriters for the Installation of Air Con- ditioning, Warm Air Heating and Ventilating Systems. Pamphlets No. 90A and 90B.
The warm air supply duct from the unit through a wall fabricated of combustible material may be installed without clearance. However, minimum clearances for the unit must be observed as shown in Prod- uct Data Book applicable to your model*.
The outlet duct should be provided with an access panel.
For vertical airflow, the ductwork should be attached to the roof curb prior to installing the unit. Ductwork dimensions are shown in the PRC roof curb installation manual.
If desired, supply and return duct connections to the unit may be made with flexible connections to reduce possible unit operating sound transmission.
FILTERS
CAUTION
TO AVOID PROPERTY DAMAGE DUE TO FIRE AND LOSS OF EQUIPMENT EFFICIENCY OR EQUIPMENT DAMAGE DUE TO DUST AND LINT BUILD UP ON INTERNAL PARTS, NEVER OPERATE UNIT WITHOUT A FILTER INSTALLED.
be filled either before a cooling startup or during a unit
drop at outlet 
90° ELL
Condensate
Drain Trap
3/4" PVC
Figure 13 - Condensate Drain Connection
NORMALSEQUENCEOFOPERATION
NOTE: There is a fan delay on initial power to unit before the low voltage board resets and is operational.
1.Thermostat calls for heating or cooling. The compressor and outdoor fan are energized.
2.Approximately 10 seconds later, the indoor fan starts.
3.The unit will deliver heating or cooling to the conditioned space until the thermostat is satisfied.
NOTE: PHD60 Two-Stage Cooling
If the room temperatures is 4°F higher than thermostat setpoint, the indoor fan will run at high speed, and the compressor at full load. If the room temperature is within 2°F of thermostat setpoint; the indoor fan will shift to low speed and the compressor will unload to a lower capacity.
4.The compressor and outdoor fan will be
5.The indoor fan continues to run for approximately 30 seconds after the thermostat is satisfied. This allows additional cooling from the indoor coil to be transferred to the conditioned space. Then, the indoor fan stops.
STARTUP AND ADJUSTMENT
Even though a return air filter is not supplied with this unit, there must be a means of filtering all return air.
Refer to Product Data Book applicable to your model* for filter size information.
If using the Over/Under Transition Kit, the filter(s) may be located in the return air duct(s) or return air filter grille(s). Filters installed exter- nal to the unit should be sized in accordance with their manufacturer recommendations. A throwaway filter must be sized for a maximum face velocity of 300 feet per minute.
FILTER INSTALLATION
Important: When installing a filter, the air flow arrows on the filter must point toward the circulating air blower.
CONDENSATE DRAIN
WARNING
TO PREVENT PERSONAL INJURY OR DEATH, ALWAYS DISCONNECT THE ELECTRICAL POWER BEFORE INSPECTING OR SERVICING THE UNIT. SINCE ALL OF THE COMPRESSOR PROTECTION DEVICES RESET AUTOMATICALLY, THE CONTACTOR AND OUTDOOR FAN MAY BE ENERGIZED WHEN RESET.
CAUTION
THIS UNIT MUST NOT BE USED AS A "CONSTRUCTION HEATER" DURING THE FINISHING PHASES OF CONSTRUCTION ON A NEW STRUCTURE. THIS TYPE OF USE MAY RESULT IN PREMATURE FAILURE OF THE UNIT DUE TO EXTREMELY LOW RETURN AIR TEMPERATURES AND EXPOSURE TO VERY DIRTY ATMOSPHERES.
CONDENSATE DRAIN CONNECTION
An external condensate drain trap is required with this unit. See your distributor for details. For proper unit operation, the trap must
COMPRESSOR PROTECTION DEVICES
The PHB**C and PHD**C compressor includes components which are designed to protect the compressor against abnormal operating conditions.
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