System Operation - Lennox XP16 Series Unit Information

Table 2. HFC−410A Temperature (°F) −
Pressure (Psig)
°F Psig °F Psig
32 100.8 63 178.5
33 102.9 64 181.6
34 105.0 65 184.3
35 107.1 66 187.7
36 109.2 67 190.9
37 111.4 68 194.1
38 113.6 69 197.3
39 115.8 70 200.6
40 118.0 71 203.9
41 120.3 72 207.2
42 122.6 73 210.6
43 125.0 74 214.0
44 127.3 75 217.4
45 129.7 76 220.9
46 132.2 77 224.4
47 134.6 78 228.0
48 137.1 79 231.6
49 139.6 80 235.3
50 142.2 81 239.0
51 144.8 82 242.7
52 147.4 83 246.5
53 150.1 84 250.3
54 152.8 85 254.1
55 155.5 86 258.0
56 158.2 87 262.0
57 161.0 88 266.0
58 163.9 89 270.0
59 166.7 90 274.1
60 169.6 91 278.2
61 172.6 92 282.3
62 175.4 93 286.5
°F Psig °F Psig
94 290.8 125 445.9
95 295.1 126 451.8
96 299.4 127 457.6
97 303.8 128 463.5
98 308.2 129 469.5
99 312.7 130 475.6
100 317.2 131 481.6
101 321.8 132 487.8
102 326.4 133 494.0
103 331.0 134 500.2
104 335.7 135 506.5
105 340.5 136 512.9
106 345.3 137 519.3
107 350.1 138 525.8
108 355.0 139 532.4
109 360.0 140 539.0
110 365.0 141 545.6
111 370.0 142 552.3
112 375.1 143 559.1
113 380.2 144 565.9
114 385.4 145 572.8
115 390.7 146 579.8
116 396.0 147 586.8
117 401.3 148 593.8
118 406.7 149 601.0
119 412.2 150 608.1
120 417.7 151 615.4
121 423.2 152 622.7
122 428.8 153 630.1
123 434.5 154 637.5
124 440.2 155 645.0
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System Operation

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.
SECOND−STAGE OPERATION
If the board receives a call for second−stage compressor
operation Y2 in heating or cooling mode and the first-stage
compressor output is active, the second-stage compressor
solenoid output will be energized.
If first-stage compressor output is active in heating mode
and the outdoor ambient temperature is below the selected
compressor lock−in temperature,
compressor solenoid output will be energized without the Y2
input. If the jumper is not connected to one of the
temperature selection pins on P3 (40, 45, 50, 55°F), the
default lock−in temperature of 40°F (4.5°C) will be used.
The board de−energizes the second-stage compressor
solenoid output immediately when the Y2 signal is removed
or the outdoor ambient temperature is 5°F above the
selected compressor lock−in temperature, or the first-stage
compressor output is de−energized for any reason.
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 he 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). System should be left in
the emergency heat mode at least six hours to allow the
crankcase heater sufficient time to prevent compressor
slugging.
FILTER DRIER
The unit is equipped with a large−capacity bi−flow filter drier
which keeps the system clean and dry. If replacement is
necessary, order another of like design and capacity. The
replacement filter drier must be suitable for use with
HFC−410A refrigerant.
the second-stage
XP16