Two−Speed Control (Tsc6) - Lennox HP21 Series Installation Instructions Manual

Table 5
Normal Operating Pressures
Out. Coil −36
Mode
Entering Entering
Air Temp.
Liq. Suc.
5F (5C)
75° (24°) 175
85 °(29°)
Cooling g
208
TXV TXV
95° (35°) 245
Only Only
105° ( 41°) 277
20° (−7°) 180
30° (−1°) 191
Heating Heating
All Units
40° (4°) 206
50° (10°) 225
IMPORTANT
Use table 5 to perform maintenance checks. Table 5
is not a procedure for charging the system. Minor
variations in these pressures may be due to differ-
ences in installations. Significant deviations could
mean that the system is not properly charged or that
a problem exists with some component in the system.
Two−Speed Control (TSC6)
Electrostatic Discharge (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic com-
ponents. Take precautions during furnace installa-
tion and service to protect the furnace's electronic
controls. Precautions will help to avoid control ex-
posure to electrostatic discharge by putting the fur-
nace, the control and the technician at the same
electrostatic potential. Neutralize electrostatic
charge by touching hand and all tools on an un-
painted unit surface, such as the gas valve or blower
deck, before performing any service procedure.
The two−speed control changes the speed of the compres-
−48 −60
Liq. Suc. Liq. Suc.
74 177 80 182
76 190 84 213
78 228 86 242
80 266 88 276
33 160 32 175
40 171 40 185
49 184 50 206
59 204 62 227
sor based on demands from the indoor thermostat. See fig-
ure 15 for TSC6 control component identification. The con-
trol features diagnostic lights and the capability of storing
diagnostic codes.
You may choose various modes of operation by changing
the jumper selections. A manual override button is located
on the control to bypass some time delays and to display
76
memorized problem codes. The control allows for two dif-
79
ferent compressor safety options to be used with an op-
80
tional safety device such as a low ambient kit. The control
82
is also equipped with a service light relay. Diagnostic
lights indicate in which speed the unit is operating, if the
31
control is functioning properly, and if any failures or fault
38
conditions exist.
47
Safety Lockout Conditions
57
D If the motor windings overheat, the TSC6 will stop the
compressor. The compressor stops operating for either a
minimum of five minutes or until the motor windings cool to
a temperature within a specified range.
The control will lock out the compressor operation for
D
five minutes when a safety device (high pressure
switch) terminates operation.
Compressor operation will lock out if overheating or
D
compressor safety devices interrupt the compressor
operation three times during one thermostat demand.
Compressor operation is locked out until the thermo-
stat demand is removed or power supply to control is
removed.
The control has an adjustment potentiometer (POT)
D
which is used for setting the low speed lockout tempera-
ture. The adjustment range is 38°F to 55°F +/− 2°F
(3.3°C to 12.78°C, +/− 1.1°C). This lockout will occur in
both heating and cooling modes.
Time Delays
Speed Change Delay − provides a one−minute delay be-
tween speed changes which cannot be bypassed.
Short Cycle Protection Delay − prevents compressor
from short cycling with a five minute timed−off delay.
This delay may be bypassed by pushing the override
button on the control.
Thermostat Bounce Delay − ignores any momentary
openings or closing of the thermostat inputs, for three
seconds, which avoids increased cycling due to ther-
mostat switch bounces.
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