GPC14H Installation Manual

10
SUGGESTED FIELD TESTING/TROUBLE SHOOTING
1. Run unit in the heating mode (room thermostat calling for
heat).
2. Check unit for proper charge. Note: Bands of frost on the
condenser coil indicate low refrigerant charge.
3. Shut off power to unit.
4. Disconnect outdoor fan by removing the outdoor fan motor
wire from “DF2” on defrost control.
5. Restart unit and allow frost to accumulate.
6. After a few minutes of operation, the unit’s defrost thermostat
should close. To verify this, check for 24 volts between “DFT”
and “C” on board. If the temperature at the thermostat is
less than 28° F and the thermostat is open, replace the
unit’s defrost thermostat, as it is defective.
7. When the unit’s defrost thermostat has closed, short the
test pins on the defrost board until the reversing valve shifts,
indicating defrost. This should take up to 22 seconds
depending on what timing period the control is set on. After
defrost initiation, the short must instantly be removed or the
unit’s defrost period will only last 3 seconds.
8. The control is shipped from the factory with the compressor
delay option selected. This will de-energize the compressor
contactor for 30 seconds on defrost initiation and defrost
termination. If the jumper is set to Normal, the compressor
will continue to run during defrost initiation and defrost
termination. The control will also ignore the low pressure
switch connected to R-PS1 and PS2 for 5 minutes upon
defrost initiation and 5 minutes after defrost termination.
9. After the unit’s defrost thermostat has terminated, check
the defrost thermostat for 24 volts between “DFT” and “C”.
The reading should indicate 0 volts (open sensor).
10. Shut off power to unit.
11. Replace outdoor fan motor lead to terminal “DF2” on defrost
board and turn on power.
AIR FLOW MEASUREMENT AND ADJUSTMENT
After reviewing section on DUCTING, proceed with airflow
measurements and adjustments. Unit’s blower curves (in
Specification Sheets) are based on external static pressure
(ESP, in. of W.C.). The duct openings on the unit are considered
internal static pressure, so as long as ESP is maintained,
the unit will deliver the proper air up to the maximum static
pressure listed for the CFM required by the application (i.e.
home, building, etc.).
In general 400 CFM per ton of cooling capacity is a rule of
thumb. Some applications depending on the sensible and
latent capacity requirements may need only 350 CFM or up
to 425 CFM per ton. Check condition space load
requirements (from load calculations) and equipment
expanded ratings data to match CFM and capacity.
After unit is set and ducted, verify ESP with a 1" inclined
manometer with pitot tubes or a Magnahelic gauge and confirm
CFM to blower curves in the specification sheets. All units have
multiple speed blower motors. If factory selected speed is not
utilized, the speed tap can be changed. Never run CFM below
350 CFM per ton, evaporator freezing or poor unit performance
is possible.
ADJUSTING SPEED TAP
FOR INDOOR BLOWER MOTOR
PSC Motor
Adjust the CFM for the unit by changing the speed tap of
the indoor blower motor at the EBTDR “com” connection
with one of the speed taps on “M1” or “M2”. (Black-High
Speed, Blue-Medium Speed, Red-Low Speed.)
EEM Motor
The blower motor speed for the EEM motor is controlled by
three 24V low voltage leads: green, yellow, and white. The
green lead sets the speed for fan-only mode. The yellow lead
sets the speed for cooling and heat pump heating mode (if
applicable). The white lead sets the speed for electric
heat mode (emergency heat and second stage heat, if
applicable).
The leads are factory connected as follows: Green to T1,
Yellow to T2, and White to T3. T1 is the low speed setting
and is dedicated to fan-only mode. T2 is medium speed
cooling and T3 is medium speed heating. T4 is high speed
cooling and T5 is high speed heating. To adjust the blower
speed, move the yellow and/or white wires to T4 and T5.
NOTE: If more than one lead is energized at the same
time, the motor will use the higher speed setting.
NOTE: *PC14 and *PH14 units are rated for a maximum
E.S.P. of 0.8 except when using a 20kw electric heater.
(The maximum static for 20 kW electric heat is 0.5 E.S.P.)
When these units are installed in the 0.5 - 0.8 E.S.P. range,
the white lead (electric heat) must be moved to T5 for proper
operation of the electric heaters.
See CFM vs ESP tables in this manual.
Refrigerant Charge Check (Units with Fixed Orifice Devices)
After completing airflow measurements and adjustments the
unit’s refrigerant charge must be checked. All package units
with fixed orifice devic
es are charged using the super heat
method at the compressor suction line. After superheat is
adjusted it is recommended to check unit sub-cooling at the
condenser coil liquid line out. For charge adjustments, see
superheat and subcooling charts shown for each model.
SUPERHEAT CAN BE DETERMINED AS FOLLOWS:
1. Read suction pressure. Determine Saturated Suction Tem-
perature from tables or pressure gauge saturated temperature
scale (R-410A).
2. Read suction line temperature.
3. Use the following formula:
SUPERHEAT = SUCTION LINE TEMP - SAT. SUCTION TEMP.