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Z−Start Capacitor (C7) −024 model only
All 2 ton HPXA19 units are equipped with a start capacitor
(C7). The capacitor is located in the control box and wired
in parallel with the compressor side of the dual capacitor.
C7 is de−energized by potential relay K31 when the com-
pressor nears full speed.
AA−Potential Relay (K31) −024 model only
All 2 ton HPXA19 units are equipped with potential relay
K31, which controls the operation of the starting circuit. The
relay is located inside the control box and is normally
closed when contactor K1 is de−energized. When K1 is en-
ergized the compressor begins start up. K31 remains
closed closed during start up and capacitor C7 remains in
the circuit. When the compressor reaches 75% of its
speed, K31 is energized, de−energizing capacitor C7.
III−REFRIGERANT SYSTEM
Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (sweat connections). Use Lennox
L15 series line sets as shown in table 7.
Separate liquid and suction service ports are provided at
the service valves for connection of gauge manifold during
charging procedure. Figure 22 shows HPXA19 refrigerant
flow and gauge manifold connections.
TABLE 7
M d l
Valve Field Size
Connections
Recommended Line Set
Model
Liquid
Line
Vapor
Line
Liquid
Line
Vapor
Line
L15
Line Sets
−024,−
036
3/8 in.
10 mm
7/8 in.
22 mm
3/8 in.
10 mm
7/8 in.
19 mm
L15−65
15 ft. − 50 ft.
4.6 m − 15 m
−038
3/8 in.
10 mm
7/8 in.
22 mm
3/8 in.
10 mm
7/8 in.
22 mm
L15−65
15 ft. − 50 ft.
4.6 m − 15 m
−048
3/8 in.
10 mm
1−1/8 in.
29 mm
3/8 in.
10 mm
7/8 in.
22 mm
L15−65
15 ft. − 50 ft.
4.6 m − 15 m
−060
3/8 in.
10 mm
1−1/8 in.
29 mm
3/8 in.
10 mm
1−1/8 in.
29 mm
Field
Fabricated
HPXA19 COOLING CYCLE
(Showing Gauge Manifold Connections)
NOTE−Use gauge ports on vapor line valve and liquid valve for evacuating refrigerant lines
and indoor coil. Use suction gauge port to measure suction pressure during charging.
OUTDOOR
COIL
EXPANSION/
CHECK VALVE
BIFLOW
FILTER / DRIER
TO
R410A
DRUM
LOW
PRESSURE
HIGH
PRESSURE
COMPRESSOR
REVERSING VALVE
VAPOR
LINE
VALVE
MUFFLER
NOTE − ARROWS INDICATE
DIRECTION OF REFRIGERANT FLOW.
REFRIGERANT WILL FLOW IN OPPOSITE
DIRECTION IN HEATING CYCLE.
SERVICE
PORT
SUCTION
EXPANSION/CHECK
VALVE
INDOOR UNIT
OUTDOOR UNIT
LIQUID
LINE
SERVICE
PORT
GAUGE MANIFOLD
DISTRIBUTOR
INDOOR
COIL
FIGURE 22
