Page 19
XP15 SERIES
Table 12. HFC−410A Temperature (°F) −
Pressure (Psig)
°F
Psig
°F
Psig
°F
Psig
°F
Psig
32
100.8
63
178.5
94
290.8
125
445.9
33
102.9
64
181.6
95
295.1
126
451.8
34
105.0
65
184.3
96
299.4
127
457.6
35
107.1
66
187.7
97
303.8
128
463.5
36
109.2
67
190.9
98
308.2
129
469.5
37
111.4
68
194.1
99
312.7
130
475.6
38
113.6
69
197.3
100
317.2
131
481.6
39
115.8
70
200.6
101
321.8
132
487.8
40
118.0
71
203.9
102
326.4
133
494.0
41
120.3
72
207.2
103
331.0
134
500.2
42
122.6
73
210.6
104
335.7
135
506.5
43
125.0
74
214.0
105
340.5
136
512.9
44
127.3
75
217.4
106
345.3
137
519.3
45
129.7
76
220.9
107
350.1
138
525.8
46
132.2
77
224.4
108
355.0
139
532.4
47
134.6
78
228.0
109
360.0
140
539.0
48
137.1
79
231.6
110
365.0
141
545.6
49
139.6
80
235.3
111
370.0
142
552.3
50
142.2
81
239.0
112
375.1
143
559.1
51
144.8
82
242.7
113
380.2
144
565.9
52
147.4
83
246.5
114
385.4
145
572.8
53
150.1
84
250.3
115
390.7
146
579.8
54
152.8
85
254.1
116
396.0
147
586.8
55
155.5
86
258.0
117
401.3
148
593.8
56
158.2
87
262.0
118
406.7
149
601.0
57
161.0
88
266.0
119
412.2
150
608.1
58
163.9
89
270.0
120
417.7
151
615.4
59
166.7
90
274.1
121
423.2
152
622.7
60
169.6
91
278.2
122
428.8
153
630.1
61
172.6
92
282.3
123
434.5
154
637.5
62
175.4
93
286.5
124
440.2
155
645.0
INSTALLING SERVICE VALVE CAPS
Disconnect gauge set and re−install all service valve caps.
INSTALL CAPS
OUTDOOR UNIT
SERVICE VALVE
Figure 29. Installing Service Valve Port Caps
System Operations
The outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch
is in the
ON
position, the indoor blower operates
continuously.
THERMOSTAT OPERATION
Some indoor thermostats incorporate isolating contacts
and an emergency heat function (which includes an amber
indicating light). The thermostat is not included with the
unit and must be purchased separately.
EMERGENCY HEAT (AMBER LIGHT)
An emergency heat function is designed into some room
thermostats. This feature is applicable when isolation of the
outdoor unit is required, or when auxiliary electric heat is
staged by outdoor thermostats. When the room thermostat is
placed in the emergency heat position, the outdoor unit
control circuit is isolated from power and field-provided relays
bypass the outdoor thermostats. An amber indicating light
simultaneously comes on to remind the homeowner that the
unit is operating in the emergency heat mode.
Emergency heat is usually used during an outdoor unit
shutdown, but it should also be used following a power
outage if power has been off for over an hour and the
outdoor temperature is below 50°F (10°C). The system
should be left in the emergency heat mode at least six
hours to allow the crankcase heater sufficient time to
prevent compressor slugging.
HIGH-PRESSURE SWITCH
XP15 units are equipped with a high-pressure switch that
is located in the liquid line to the compressor. The normally
closed SPST auto−reset switch opens at 590 psi.
LOW-PRESSURE SWITCH
XP15 units are equipped with a low-pressure switch that is
located in the vapor line to the compressor. The normally
closed SPST auto−reset switch opens at 25 psi and closes
at 40 psi.
SINGLE-SPEED CONDENSER FAN MOTOR
The XP15 is equipped with a single-speed condenser fan
motor. The compressor contactor and defrost control
board (DCB) controls the operation of the motor.
FILTER DRIER
The unit is equipped with a large−capacity biflow filter drier
which keeps the system clean and dry. If replacement is
necessary, order another of like design and capacity.
Replacement filter driers must be suitable for use with
HFC−410A refrigerant.
Lennox System Operation Monitor
(LSOM)
The LSOM detects the most common fault conditions in
the system. When an abnormal condition is detected, the
LSOM communicates the specific condition through its
ALERT and TRIP lights. The LSOM is capable of detecting
both mechanical and electrical system problems. See
figure 30 for LSOM LED locations.
Figure 30. LSOM
TRIP LED
POWER LED
ALERT LED
