Cooling System; Preliminary Operation Cooling; Cooling Sequence Of Operation; Heating Sequence Of Operation - York Sunline 2000 Installation Instruction

511.06-N5Y

COOLING SYSTEM

The unit has an air-cooled condenser and is factory-charged
with Refrigerant-22.
The compressor is hermetically sealed, internally sprung,
mounted on spring isolators and inherently (internally)
protected. If there is an abnormal temperature rise in the
compressor, the protector will open to shut down the
compressor.

PRELIMINARY OPERATION COOLING

After the installation has been completed, the crankcase heater
of the compressor must be energized for at least 4 hours before
starting the unit. After this initial warm-up, the compressor
should be given three false starts (energized just long enough
to make a few revolutions) with a 5 minute delay between each
start before being put into full time service.
NOTE: Prior to each cooling season, the crankcase heater
must be energized at least 10 hours before the system
is put into operation.

COOLING SEQUENCE OF OPERATION

When the thermostat calls for cooling, the compressor and the
outdoor fan motor will be energized through terminal "Y1" and
the supply air blower motor will be energized through terminal
"G" (if the fan switch on the subbase is set in the "AUTO"
position). The supply air blower motor will run continuously if
the fan switch is set in the "ON" position.
The reversing valve is energized thru the "O" circuit when the
subbase is in the cooling mode.

HEATING SEQUENCE OF OPERATION

The following sequence of operation is based on using a
standard YORK heat pump thermostat with two heating stages.
FIRST STAGE HEAT
When the thermostat calls for heating, the compressor and the
outdoor fan motor will be energized through terminal "Y1" and
the supply air blower motor will be energized through terminal
"G" (if the fan switch on the subbase is set in the "AUTO"
position). The supply air blower motor will run continuously if
the fan switch is set in the "ON" position.
SECOND STAGE HEAT
If compressor operation can not satisfy the heating
requirements, second stage heat will energize supplemental
electric heat (if supplied) thru the "W1" circuit.

DEFROST SEQUENCE OF OPERATION

The BCH has a unique "ambient modified" time-temperature
defrost control that automatically adjusts to changes in the
outdoor temperature. The defrost control will shorten the
defrost initiation time periods above 35 F and will extend the
defrost initiation time periods below 35 F. The control is factory
set to defrost at 110 minutes (T3), but it can be field adjusted
to defrost at 80 minutes (T2) or 50 minutes (T1) in areas with
high humidity.
The curve in Figure 7 shows how defrost initiation times are
automatically compensated for changes in outdoor
temperature.
12
OPERATION
250
200
150
100
50
0
-10
FIG. 7 - DEFROST INITIATION TIMES
EXAMPLE: If the time is factory set on pin T-3 (110 minutes at
35 F outdoor) and the outdoor temperature climbs to 45 F, the
time initiation cycle will decrease to every 100 minutes.
If the outdoor temperature drops to 10 F where ice is less likely
to form, the 110 minute interval will extend to every 150
minutes.
Two requirements must be met before a defrost cycle can be
initiated.
1. The defrost time cycle must be complete.
2. The liquid line temperature must be less than 28 F.
Defrost will terminate when the liquid line sensor reaches 55 F
or after 10 minutes.
The defrost time cycle will restart 10 minutes after the start of
the defrost cycle even though the liquid sensor terminated
defrost after 3 minutes.
During troubleshooting, the defrost time can be reduced to 20
seconds by shorting out the SW1 test pegs on the module. The
pegs are 1/2" long, 3/16" apart and are mounted on a white
base. See Figure 8.
T2 - 80 MINUTE SETTING
T3 - 110 MINUTE SETTING
(Factory Set Point)
SHORTING PEGS TO
OVERRIDE TIMER
FOR SERVICE
MOVABLE JUMPER
WIRE TO CHANGE
DEFROST TIMER
FIG. 8 - AMBIENT MODIFIED TIME/TEMPERATURE
CONTROL
T3 - 110 Minute Setting (Factory Set Point)
T2 - 80 Minute Setting
T1 - 50 Minute Setting
10 20
0 30
OUTDOOR AMBIENT, DEG. F
T1 - 50 MINUTE SETTING
Unitary Products Group
60
40 50