System Operations - Lennox XP21 Series Installation Instructions Manual

°F Psig °F Psig
32 100.8 48 137.1
33 102.9 49 139.6
34 105.0 50 142.2
35 107.1 51 144.8
36 109.2 52 147.4
37 111.4 53 150.1
38 113.6 54 152.8
39 115.8 55 155.5
40 118.0 56 158.2
41 120.3 57 161.0
42 122.6 58 163.9
43 125.0 59 166.7
44 127.3 60 169.6
45 129.7 61 172.6
46 132.2 62 175.4
47 134.6
INSTALLING ISOLATION GROMMETS
Locate the isolation grommets (provided). Slide grommets
onto vapor and liquid lines. Insert grommets into piping
panel to isolate refrigerant lines from sheet metal edges.
SUCTION LINE
LIQUID LINE
TWO ISOLATION GROMMETS ARE
PROVIDE FOR THE LIQUID AND
SUCTION LINE PIPE PANEL PASS
THROUGH.
REAR VIEW OF UNIT EXTERIOR
Figure 23. Isolation Grommets

System Operations

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.
506601−01
.
Table 9 HFC−410A Temperature (°F) − Pressure (Psig)
°F Psig °F Psig
63 178.5 79 231.6
64 181.6 80 235.3
65 184.3 81 239.0
66 187.7 82 242.7
67 190.9 83 246.5
68 194.1 84 250.3
69 197.3 85 254.1
70 200.6 86 258.0
71 203.9 87 262.0
72 207.2 88 266.0
73 210.6 89 270.0
74 214.0 90 274.1
75 217.4 91 278.2
76 220.9 92 282.3
77 224.4 93 286.5
78 228.0
PIPING PANEL
Page 32
°F Psig °F Psig
94 290.8 110 365.0
95 295.1 111 370.0
96 299.4 112 375.1
97 303.8 113 380.2
98 308.2 114 385.4
99 312.7 115 390.7
100 317.2 116 396.0
101 321.8 117 401.3
102 326.4 118 406.7
103 331.0 119 412.2
104 335.7 120 417.7
105 340.5 121 423.2
106 345.3 122 428.8
107 350.1 123 434.5
108 355.0 124 440.2
109 360.0
The heat pump control (A175) provides the following
functions:
S
Demand defrost algorithm
S
Field−selectable defrost termination temperatures
S
Internal switching of outputs
S
Compressor anti−short−cycle delay.
S
Five−strikes lockout safety function
S
High (S4) and low (S87) pressure switches
S
Ambient (RT13), coil (RT21) and discharge line
(RT28) temperatures monitoring and protection.
COMPRESSOR PROTECTION
CYCLE DELAY
The heat pump control protects the compressor from:
S
Short cycling (five minutes) when there is initial power
up
S
Interruption in power to the unit
S
Pressure or sensor trips
S
Delay after Y1 demand is removed.
In non−communicating systems the delay is set for 300
seconds (five minutes) and can not be changed. To
override timer when active or inactive, place a jumper on
the field test pins between 1 and 2 seconds.
In communicating system, the icomfort Touch
has a separate built−in 5−minute non−adjustable short cycle
protection.
°F Psig °F Psig
141 545.6
125 445.9
126 451.8 142 552.3
127 457.6 143 559.1
128 463.5 144 565.9
129 469.5 145 572.8
130 475.6 146 579.8
131 481.6 147 586.8
132 487.8 148 593.8
133 494.0 149 601.0
134 500.2 150 608.1
135 506.5 151 615.4
136 512.9 152 622.7
137 519.3 153 630.1
138 525.8 154 637.5
139 532.4 155 645.0
140 539.0
ANTI−SHORT
® thermostat