System Operation - Lennox TPA036H4N4 Installation Instructions Manual

Table 7. HFC−410A Temp. (°F) − Pressure (Psig)
°F Psig °F Psig
−40 10.1 21 80.5
−35 13.5 22 82.3
−30 17.2 23 84.1
−25 21.4 24 85.9
−20 25.9 25 87.8
−18 27.8 26 89.7
−16 29.7 27 91.6
−14 31.8 28 93.5
−12 33.9 29 95.5
−10 36.1 30 97.5
−8 38.4 31 99.5
−6 40.7 32 100.8
−4 43.1 33 102.9
−2 45.6 34 105.0
0 48.2 35 107.1
36 109.2
1 49.5
2 50.9 37 111.4
3 52.2 38 113.6
4 53.6 39 115.8
5 55.0 40 118.0
6 56.4 41 120.3
7 57.9 42 122.6
8 59.3 43 125.0
9 60.8 44 127.3
10 62.3 45 129.7
11 63.9 46 132.2
12 65.4 47 134.6
13 67.0 48 137.1
14 68.6 49 139.6
15 70.2 50 142.2
16 71.9 51 144.8
17 73.5 52 147.4
18 75.2 53 150.1
19 77 54 152.8
20 78.7 55 155.5

System Operation

SECOND−STAGE OPERATION
If the demand defrost control (A108) 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, the second-stage
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.
IMPORTANT
Some scroll compressor have internal vacuum protector
that will unload scrolls when suction pressure goes
below 20 psig. A hissing sound will be heard when the
compressor is running unloaded. Protector will reset
when low pressure in system is raised above 40 psig. DO
NOT REPLACE COMPRESSOR.
506650−01
°F Psig °F Psig
56 158.2 91 278.2
57 161.0 92 282.3
58 163.9 93 286.5
59 166.7 94 290.8
60 169.6 95 295.1
61 172.6 96 299.4
62 175.4 97 303.8
98 308.2
63 178.5
64 181.6 99 312.7
65 184.3 100 317.2
66 187.7 101 321.8
67 190.9 102 326.4
68 194.1 103 331.0
69 197.3 104 335.7
70 200.6 105 340.5
71 203.9 106 345.3
72 207.2 107 350.1
73 210.6 108 355.0
74 214.0 109 360.0
75 217.4 110 365.0
76 220.9 111 370.0
77 224.4 112 375.1
78 228.0 113 380.2
79 231.6 114 385.4
80 235.3 115 390.7
81 239.0 116 396.0
82 242.7 117 401.3
83 246.5 118 406.7
84 250.3 119 412.2
85 254.1 120 417.7
86 258.0 121 423.2
87 262.0 122 428.8
88 266.0 123 434.5
89 270.0 124 440.2
90 274.1
125 445.9
UNIT COMPONENTS
High Pressure Switch (S4)
When the high pressure switch trips, the demand defrost
control will cycle off the compressor, and the strike counter
in the demand defrost control will count one strike. High
Pressure (auto reset) − trip at 590 psig, reset at 418.
Low Pressure Switch (S87)
When the low pressure switch trips, the demand defrost
control will cycle off the compressor, and the strike counter
in the demand defrost control will count one strike. Low
pressure switch (auto reset) − trip at 25 psig, reset at 40
psig.
The low pressure switch is ignored under the following
conditions:
S
During the defrost cycle and 90 seconds after the
termination of defrost
S
When the average ambient sensor temperature is
below 15° F (−9°C)
S
For 90 seconds following the start up of the
compressor
S
During test mode
Ambient Sensor (RT13)
The ambient sensor considers outdoor temperatures
below −35°F (−37°C) or above 120°F (48°C) as a fault. If the
ambient sensor is detected as being open, shorted or out
of the temperature range of the sensor, the demand
defrost control will not perform demand defrost operation.
The demand defrost control will revert to time/temperature
defrost operation and will display the appropriate fault
code. Heating and cooling operation will be allowed in this
fault condition.
Coil Sensor (RT21)
Coil Sensor The coil temperature sensor considers
outdoor temperatures below −35°F (−37°C) or above 120°F
(48°C) as a fault. If the coil temperature sensor is detected
as being open, shorted or out of the temperature range of
the sensor, the demand defrost control will not perform
demand or time/temperature defrost operation and will
display the appropriate fault code. Heating and cooling
operation will be allowed in this fault condition.
High Discharge Temperature Sensor (RT28)
If the discharge line temperature exceeds a temperature of
285°F (140°C) during compressor operation, the demand
defrost control will de−energize the compressor contactor
output (and the defrost output, if active). The compressor
will remain off until the discharge temperature has dropped
below 225°F (107°C) and the 5-minute anti−short cycle
delay has been satisfied. This sensor has two fault and
lockout codes:
1. If the demand defrost control recognizes five high
discharge line temperature faults during a single (Y1)
compressor demand, it reverts to a lockout mode and
displays the appropriate code. This code detects
shorted sensor or high discharge temperatures. Code
on demand defrost control
Temperature Fault and Lockout.
2. If the demand defrost control recognizes five
temperature sensor range faults during a single (Y1)
Page 26
is Discharge Line