Lennox HS21 Series User manual

Page 1  1999 Lennox Industries Inc.
Litho U.S.A.
Corp. 9406-L3
HS21
Service Literature
EARLY / LATE
MODEL SERIES
Revised 10-2000
HS21 SERIES UNITS
S21 early model units ( -411, -511, -651) and late model
units (-036, -048, -060) are high efficiency residential splitĆ
system condensing units which features a twoĆspeed
compressor. Models are available in sizes ranging from 3
through 5 tons in either single or threeĆphase configuration.
The series features solidĆstate twoĆspeed control, which regĆ
ulates compressor speed in response to thermostat
demand. The S21 is designed for use with an expansion
valve at the indoor coil.
This manual is divided into sections which discuss the comĆ
ponents, refrigerant system, charging procedures,
maintenance and operation sequences.
Information contained in this manual is intended for use by
qulified service technicians only. All specifications are
subject to change. Procedures outlined in this manual are
presented as a recommendation only and do not superĆ
sede or replace local or state codes. In the absence of
local or state codes, the guidelines and procedures outĆ
lined in this manual (except where noted) are
recommended only.
LATE
MODEL
S21 S OWN
ELECTRICAL DATA (Early Model)
SPECIFICATIONS (Early Model)
Model No. HS21 411
HS21 413
HS21 511
HS21 513
HS21 651
HS21 653
Condenser Coil
Condenser Fan
Refrigerant Charge ( CFCĆ22)
Face area (sq.ft.)
Tube diameter (in.)
No. of Rows
Fins per inch
Diameter (in.)
No. of Blades
Motor hp
Cfm
Rpm
Watts
Liquid line connection (sweat)
Suction line connection (sweat)
Model No.
Line voltage data Ć 60hz.
Compressor
Rated load amps
Power factor
Locked rotor amps
Outdoor Coil
Fan Motor
Full load amps
Locked rotor amps
Max fuse or circuit breaker size (amps)
*Minimum circuit ampacity
HS21 511 HS21 513 HS21 651 HS21 653
208/230/1ph 208/230/3ph208/230/3ph 208/230/1ph208/230/1ph 208/230/3ph
334
90.0 60.0 120.0 85.0 141.0 91.0
outside / inside
21.64/
20.81
21.64/
20.81
23.92/
23.01
3/8 3/8 3/8
222
20 20 20
24 24 24
1/6 1/6 1/4
3200 3200 4200
815 815 815
170 310170
11lbs. 6oz. 11lbs. 14oz. 13lbs. 14oz.
3/8 3/8 3/8
7/8 7/8 1Ć1/8
17.6 12.7 21.6 15.8 30.8 19.9
.98 .90 .98 .90 .92 .90
1.0 1.0 1.0 1.0 1.7 1.7
1.9 1.9 1.9 1.9 2.9 2.9
40 25 45 35 60 45
23.0 16.9 28.0 20.8 40.2 26.6
HS21 411 HS21 413
*Refer to National Electrical Code Manual to determine wire, fuse and disconnect size requirements.
NOTE - Extremes of operating range are plus 10% and minus 5% of line voltage

Page 2
SPECIFICATIONS (Late Models)
Model No. HS21 036 HS21 048 HS21 060
Nominal Tonnage 3 4 5
Liq id line Ċ in. (mm) o.d. connection (sweat) 3/8 (9.5)
S ction line Ċ in. (mm) o.d. connection (sweat) 7/8 (22.2) 1Ć1/8 (28.5)
Net face area sq ft (m2)
O ter coil 21.77 (2.02) 24.06 (2.24)
Condenser
Net face area Ċ sq. ft. (m2)
Inner coil 21.11 (1.96) 23.33 (2.17)
Condenser
Coil T be diameter Ċ in. (mm) & no. of rows 5/16 (7.9) Ċ 2
Fins per inch (m) 22 (866)
Diameter Ċ in. (mm) & no. of blades 24 (610) Ċ 3 24 (610) Ċ 4
Motor hp 1/6 (124) 1/4 (187)
Condenser
Fan Cfm (L/s) 3200 (1510) 4200 (1980)
Fan
Rpm 815
Watts 170 310
*Refrigerant charge f rnished (HCFCĆ22) 10 lbs. 13 oz. (4.90 kg) 11 lbs. 3 oz. (5.07 kg) 12 lbs. 7 oz. (5.64 kg)
Shipping weight Ċ lbs. (kg) 1 package 328 (149) 329 (149) 352 (160)
OPTIONAL ACCESSORIES - MUST BE ORDERED EXTRA
Mo nting Base MB2-L (69J07)
Low Ambient Kit LB-57113BC (24H77)
Indoor Blower Speed Relay Kit 72G36
CCB1 EfficiencyPl st H midity Control 35H00
EBR1 Blower Relay Kit 75H90
Compressor Monitor (Canada Only) T6-1469 (45F08)
*Refrigerant charge is s fficient for 20 ft. (6.1 m) length line set.
ELECTRICAL DATA (Late Models)
Model No. HS21 036 HS21-048 HS21 060
Line voltage data Ċ 60 hz 208/230v - 1ph 208/230v - 3ph 208/230v - 1ph 208/230v - 3ph 208/230v - 1ph 208/230v - 3ph
Rec. Max f se/circ it breaker size (amps) 40 25 45 35 60 45
*Minim m circ it ampacity 23.0 16.9 28.0 20.8 40.2 26.6
Rated load amps 17.6 12.7 21.6 15.8 30.8 19.9
Compressor Power factor .98 .90 .98 .90 .92 .90
Locked rotor amps 90.0 60.0 120.0 85.0 141.0 91.0
Condenser Coil F ll load amps 1.0 1.0 1.0 1.0 1.7 1.7
Condenser
Coil
Fan Motor Locked rotor amps 1.9 1.9 1.9 1.9 2.9 2.9
*Refer to National or Canadian Electrical Code man al to determine wire, f se and disconnect size req irements.
NOTE Ċ Extremes of operating range are pl s 10% and min s 5% of line voltage.

Page 3
FIGURE 1
CONTROL BOX
LOW PRESSURE SWITCH
S87
HIGH PRESSURE SWITCH
(S4)
COMPRESSOR
TERMINAL BOX
MUFFLER
LIQUID LINE
THERMOMETERWELL
LIQUID LINE
SERVICE VALVE
SUCTION LINE
SUCTION LINE
SERVICE VALVE
HS21 COMPONENTS (EARLY MODEL)
-411, -511, -651
FIGURE 2
CONTROL BOX
COMPRESSOR TERMINAL BOX
LOW PRESSURE SWITCH
(S87)
HIGH PRESSURE SWITCH
(S4)
MUFFLER
THERMOMETERWELL
LIQUID LINE
SUCTION LINE
SERVICE VALVE
SUCTION LINE
HS21 COMPONENTS (LATE MODEL)
-036, -048, -060
LIQUID LINE
SERVICE VALVE

Page 4
FIGURE 3
HS21 SINGLE PHASE CONTROL BOX COMPONENTS
TWO SPEED
CONTROL
(A14)
DISCONNECT
TAB
TRANSFORMER
(T19)
DUAL
CAPACITOR
(C12)
COMPRESSOR
START CAPACITOR
(C7)
POTENTIAL
RELAY (K31)
HIGH SPEED
CONTACTOR
(K69)
LOW SPEED
CONTACTOR
(K1)
FIGURE 4
HS21 THREE PHASE CONTROL BOX COMPONENTS
TWO SPEED
CONTROL
(A14)
DISCONNECT
TAB
TRANSFORMER
(T19)
FAN CAPACITOR
(C1)
OUTDOOR FAN
RELAY (K10)
HIGH SPEED
CONTACTOR
(K69)
LOW SPEED
CONTACTOR
(K1)

Page 5
I-APPLICATION
All major components (indoor blower/coils) m st be
matched according to Lennox recommendations for the
compressor to be covered nder warranty. Refer to EngiĆ
neering Handbook for approved system match ps. A
misapplied system will ca se erratic operation, can res lt in
early fail re of compressor or other components, and co ld
affect the warranty.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic
components. Take precautions during unit instal
lation and service to protect the unit's electronic
controls. Precautions will help to avoid control
exposure to electrostatic discharge by putting
the unit, the control and the technician at the
same electrostatic potential. Neutralize electros
tatic charge by touching hand and all tools on an
unpainted unit surface before performing any
service procedure.
II-UNIT COMPONENTS
HS21 nit components are shown in fig res 1 and 2.
A-Control Box Components
HS21 control box is shown in fig res 3 and 4. The control
box is located in the top front section of the nit.
TABLE 1
HS21 Co ponent Source of Power
24VAC from
O tdoor Unit
Transformer T19
Contactor K1
Contactor K69
High Pressure Limit S4
TwoĆS eed Control A14
Line Voltage
Potential Relay K31 (1 hase)
Crankcase Heater HR1
Compressor Fan D al Capacitor
C12 (1 phase)
Compressor Start Capacitor C7
(1 phase)
Bleed Resistor R21 (1 hase)
Fan Ca acitor C1 (3 hase)
Com ressor B1
Outdoor Fan B4
Low Pressure Limit S87
Fan Relay K10 (3 hase)
1-Control Transformer T19
All nits are eq ipped with a line voltage to 24VAC
transformer which s pplies power to nit controls as
shown in table 1. The transformer is rated at 70VA and
has two primary voltage taps (red - 208V, orange -
230V, and black - common). Refer to nit wiring diaĆ
gram for detailed information regarding nit wiring.
2-Contactors K1 and K69
The compressor is energized by a set of contactors (K1 and
K69) located in the control box. Contactors in HS21 nits are
energized as shown in table 2.
Contactor K1 energizes low speed compressor operation in
all nits (singleĆphase and threeĆphase.) In singleĆphase nits
K1 is a do bleĆpole do bleĆbreak contactor and in threeĆ
phase nits K1 is a do bleĆbreak contactor with three sets of
normally open contacts and two sets of normally closed conĆ
tacts. K1 is also eq ipped with a set of singleĆpole
do bleĆthrow a xiliary contacts located on the side of the conĆ
tactor. The contactor is energized in response to low speed
thermostat demand (from twoĆspeed control jackpl g
J44/P44 pin 9).
TABLE 2
Co pressor Speed SingleĆPhase ThreeĆPhase
Low
High
K1 K1
K1 & K69 K69
Contactors Energized
In singleĆphase nits, K1 also deĆenergizes the crankcase
heater and energizes the condenser fan d ring compressor
operation.
Contactor K69 energizes high speed operation in all nits
(singleĆphase and threeĆphase). K69 is a do bleĆbreak conĆ
tactor with three sets of normally open contacts and two sets
of normally closed contacts for singleĆphase models, and is
a three pole do ble break contactor for threeĆphase models.
This contact arrangement provides niq e switching charĆ
acteristics for twoĆspeed operation. K69 is also eq ipped
with a set of singleĆpole do bleĆthrow a xiliary contacts loĆ
cated on the side of the contactor. The contactor is energized
in response to high speed thermostat demand from JP44Ć8
(twoĆspeed control jackpl g J44/P44 pin 8).

Page 6
Contactor Operation: Single Phase Units
Low speed demand energizes contactor K1. K1 deĆenĆ
ergizes the crankcase heater and energizes the
compressor and condenser fan. High speed demand
energizes both contactors K1 and K69. K69 N.O. conĆ
tacts close to redirect the circ it to the high speed start
windings and the N.C. contacts open to deĆenergize the
low speed start windings. K69-2 N.C. contacts and
K69-2 N.O. contacts also switch when K69 is energized
to ens re that K1 is energized with K69 d ring high
speed operation (refer to nit wiring diagram).
Contactor Operation: Three Phase Units
Low speed demand energizes contactor K1. K1 enerĆ
gizes the compressor and locks o t contactor K69. High
speed demand deĆenergizes K1 and energizes contacĆ
tor K69. K69 locks o t K1, thro gh the K69-1 contacts
and energizes the compressor on high speed.
K1 is wired so that when deĆenergized, the contactor forms a
parallel common connection to the motor windings for high
speed, forming a parallel Delta" connection for Copeland
compressors. When K1 is energized, the contactor forms a
series Delta connection to the compressor windings. Refer
to operation seq ence in back of this man al for more inĆ
formation.
3-Outdoor Fan Relay K10 (three phase only)
All threeĆphase HS21 series nits se an o tdoor fan
relay (K10) to control the operation of the condenser
fan and the crankcase heater. The relay energizes the
condenser fan and deĆenergizes the crankcase heater
d ring demand.
4-Potential Relay K31 (single phase only)
All singleĆphase HS21 nits se a potential relay to control the
operation of the compressor starting circ it. The relay is norĆ
mally closed when the compressor (contactor K1) is
deĆenergized. Capacitor (C7) is connected in series to a set of
normally closed K31 contacts and assists the compressor in
starting. When K1 energizes, the compressor immediately
begins startĆ p. K31 remains deĆenergized d ring compresĆ
sor startĆ p and the start capacitor (C7) remains in the circ it.
As the compressor gains speed K31 is energized by electroĆ
motive forces generated by the compressor. When K31
energizes, its contacts open to take the start capacitor o t of
the circ it.
5-Fan Capacitor C1 (three phase units only)
All threeĆphase HS21 series nits se singleĆphase permaĆ
nent split capacitor (PSC) fan motors which req ire an
external r n capacitor. Ratings will be printed on side of caĆ
pacitor.
6-Start Capacitor C7 (single phase only)
All singleĆphase HS21 nits are eq ipped with a start caĆ
pacitor connected in parallel with the compressor side of
the d al capacitor. The capacitor is switched off by the poĆ
tential relay when the compressor nears f ll speed. The
start capacitor is rated 145Ć175mfd. @ 330VAC in all singleĆ
phase nits.
7-Bleed Resistor R21 (single phase only)
All singleĆphase HS21 nits are eq ipped with a bleed resistor
connected in parallel with start capacitor C7. The resistor is
sed to slowly discharge the capacitor when not in se. R21 is
a 15,000 ohm 2 watt resistor.
8-Dual Capacitor C12 (single phase only)
All singleĆphase HS21 nits se a single d al capacitor to
maximize motor efficiency in both the fan motor and the
compressor, which se PSC motors. A d al capacitor has
two independent capacitors inside one can. Each side of the
capacitor has different ratings. Ratings will be printed on side
of capacitor. The d al capacitor is wired in parallel with the
start capacitor and is electrically connected as shown in the
nit wiring diagram.
9-Disconnect Tab
The disconnect tab has 10 pins where 10 wire connections
are made from the vario s components in the control box.
The disconnect tab simplifies the connections between the
components in the control box.
10-TSC5 Two Speed Control A14
The TSC (A14) twoĆspeed control (fig re 7) is a LennoxĆb ilt
control designed for se with twoĆspeed condensing nits.
The control provides a tomatic switching from low speed to
high speed operation and back. A14 is electrically connected
as shown in the nit wiring diagram. The two speed control is
covered in detail in section III.

Page 7
B-Unit Components
1-Compressor B1
All compressors are rated at 208/230 VAC and may be singleĆ
phase or threeĆphase. All compressors are eq ipped with
internal press re relief valves set at 450+50 psig. CompresĆ
sors in all nits se insertionĆtype crankcase heaters. See
ELECTRICAL DATA" or compressor nameplate for specifiĆ
cations. Fig re 5 shows the compressor terminal box.
FIGURE 5
T3 T8 T1 T7
SINGLE
PHASE
T2
S1 S2
TYPICAL TWOĆSPEED COMPRESSOR
TERMINAL BOX
COPELAND SINGLEĆPHASE SHOWN
2-Compressor Heater HR1 (all units)
A crankcase heater is sed on all HS21 models. The wellĆ
mo nted, insertionĆtype heater is selfĆreg lating.
Heaters are rated at 40 watts for all HS21 models. The
heater is thermostatĆact ated and operates only when
demand is satified.
3-Outdoor Fan Motor B4
The table on page 1 of this man al shows the specifications
of o tdoor fans sed in all HS21 nits. In singleĆphase nits,
the o tdoor fan is controlled by the compressor contactor
K1. In threeĆphase nits, the o tdoor fan is controlled by
relay K10. See fig re 6 if o tdoor fan motor replacement is
necessary
FAN GUARD
Condenser fan
and motor Wiring
Dri loo
FIGURE 6
1/4"
4-High Pressure Limit Switch S4
All nits are eq ipped with a SPST N.C. high press re
limit switch mo nted on the compressor discharge line.
When the press re rises above 410+10 psig, the switch
opens to sh t off the compressor. The switch is man ally
reset and is electrically connected in series with low presĆ
s re switch S87 in the twoĆspeed control's safety circ it.
5-Low Pressure Switch S87
All nits are eq ipped with a SPST N.C. low press re
switch mo nted on the compressor s ction line. The switch
opens, sh tting off the compressor, when s ction line presĆ
s re drops below 25+5 psig. When the press re rises
above 55+5 psig the switch a tomatically resets (closes).
The switch is electrically connected in series with high presĆ
s re switch S4 in the twoĆspeed control's safety circ it.
C-Optional Equipment
1-Humidity control A20
The CCB1 EfficiencyPl s Comfort Management System
may be sed with the HS21 nit to control h midity. The EfĆ
ficiencyPl s a tomatically controls the compressor and the
indoor blower, to maintain a selected level of relative h midĆ
ity thro gho t the conditioned space d ring a thermostat
demand. The EfficiencyPl s DS" o tp t is designed to diĆ
rectly control the variable speed motors sed in the CB21,
G21V, CB31MV and G32V indoor nits.
2-EBR1 Control Kit A51
EBR1 Blower Relay Kit provides the option of varying indoor
blower speeds of m ltiĆtap motors when sing the EfficienĆ
cyPl s with a twoĆspeed HS21. When the EfficiencyPl s is
sed with the HS21, most of the deh midification is provided
by forcing the compressor into high speed when the thermoĆ
stat calls for low speed. The kit provides more
deh midification by sim ltaneo sly decreasing the indoor
blower speed.
3-Room Thermostat S1
The HS21 nit can be sed with n mero s types of thermoĆ
stats. The twoĆheat two-cool electromechanical thermostat
(51H34) is recommended. The s bbase is f rnished with the
thermostat and feat res system selector switch (OffĆHeatĆ
A toĆCool) and fan switch (A toĆOn) for contin o s or
intermittent blower operation. The thermostat also has an inĆ
dicator light to indicate low or high speed compressor
operation.
4-Low Pressure (Low Ambient) Switch S11
The HS21 nit will operate satisfactorily down to 45°F (7°C)
o tdoor air temperat re witho t any additional controls. For
cases where operation of the nit is req ired at low ambiĆ
ents, a Low Ambient Control Kit LBĆ57113BC (24H77) can
be added in the field, enabling the nit to operate properly
down to 30°F (Ć1°C).

Page 8
III-TSC5 TWO SPEED CONTROL OPERATION
The TSC (A14) twoĆspeed control contains relays which
energize compressor operation in response to thermostat
demand. High speed operation can be energized and deĆ
energized witho t passing thro gh low speed. The control
also contains safety timedĆoff delays and compressor
overĆtemperat re sensing which protect the compressor.
A timedĆoff delay in the control prevents short cycling by lockĆ
ing o t compressor operation for five min tes after the end of
a thermostat demand or after a power fail re. The control also
co nts  nit fa lt conditions." When the compressor stops d e
to a safety limit trip, or if the compressor winding temperat re
becomes too hot, the control's internal cycle co nter acc m Ć
lates one fa lt. If three nit fa lts are co nted d ring the same
thermostat demand, the control locks o t" and stops all nit
operation. The control can be reset by breaking and remaking
thermostat demand. Unit fa lts are erased when power is inĆ
terr pted. When thermostat demand changes stages,
compressor operation stops for approximately one min te to
allow refrigerant press re to eq alize in the system.
A man al override b tton aids servicing and tro bleshooting,
on the control. The man al override b tton, when pressed
and released, bypasses the fiveĆmin te delay so low speed or
high speed operation can be immediately energized. HowevĆ
er, the control provides a oneĆmin te delay between speed
changes, which can not be bypassed.
Do not se the override b tton immediately after powerĆ p. If
the b tton is p shed d ring the tenĆsecond powerĆ p delay, it
has no effect. The control completes the fiveĆmin te delay.
The control contin ally selfĆtests its internal circ its and ses
the diagnostic lights to indicate control fail re.
Normal Operation Sequence
1- The control begins a fiveĆminute delay during which
the unit is not o erational (control and outdoor unit
do not res ond to thermostat demand). Once the
fiveĆminute delay is com lete, the control waits in
OFF mode for thermostat demand.
2- After receiving a thermostat demand, the TSC delays
three seconds before res onding.
3- Low s eed demand (JP44Ć9) energizes low s eed
o eration OR high s eed demand (JP44Ć8) energizes
high s eed o eration.
4- During unit o eration, if low s eed demand changes
to high s eed demand or if high s eed demand
changes to low s eed, the control delays three seĆ
conds before res onding. Then, all unit o eration
sto s for 60+5 seconds (control deĆenergizes JP44Ć8
and JP44Ć9). This allows refrigerant ressure to
equalize in the system. At the end of the 60+5 second
delay, the control res onds to whatever thermostat
demand is resent. If no thermostat demand is resĆ
ent, the control resets (see unit fault conditions
section) and returns to ste 2 above.
5- When thermostat demand is satisfied, all unit o eraĆ
tion sto s after a threeĆsecond delay (control
deĆenergizes JP44Ć8 and JP44Ć9), the control resets
(see unit fault conditions section) and returns to ste
two.
6- General O eration
On owerĆu , the control begins a tenĆsecond initial
delay.
FIGURE 7
TSC5 (A14) TWOĆSPEED CONTROL COMPONENTS
DIAGNOSTIC LEDs
D8, D4, D2, D1
Y1 LED
Y2 LED
MAIN CONTROL
PLUG
HIGH SPEED
LED
LOW SPEED
LED
SERVICE RELAY
CONNECTORS
HEARTBEAT
LED
MODE
SELECTION
JUMPERS
OPTION 1 ENABLE
JUMPER OPTION 2 ENABLE
JUMPER
OPTION 2
CONNECTOR
COMPRESSOR
SENSOR
CONNECTORS
MANUAL
OVERRIDE
BUTTON
OPTION 1
CONNECTOR

Page 9
FIGURE 8
TSC5 (A14) MAIN CONTROL PLUG
1
2
3
456
789
JP44
JP44Ć1 24VAC POWER (INPUT)
JP44Ć2 24VAC COMMON
JP44Ć3 24VAC (SPARE, NOT USED)
JP44Ć4 2nd STAGE THERMOSTAT DEMAND
JP44Ć5 THERMOSTAT COMMON (C)
JP44Ć6 1st STAGE THERMOSTAT DEMAND
JP44Ć7 24VAC FROM SAFETY SWITCHES
TO INTERNAL CONTACTOR COIL (INPUT)
JP44Ć8 HIGH SPEED (24VAC OUTPUT)
JP44Ć9 LOW SPEED (24VAC OUTPUT)
Two Speed Control Fault Conditions
If the control is in low speed operation, high speed operation,
OFF" mode or speed change delay, the control co nts" or
acc m lates fa lts on an internal cycle co nter. Only fa lts
which occ r d ring compressor operation and which ca se
the compressor to sh t off are co nted. After a fa lt is
co nted, the control stops nit operation, resets and begins a
fiveĆmin te time delay (step 2, operation seq ence). If the
control senses a fa lt at the end of five min tes, the nit will
not restart. If the control co nts three fa lts d ring the same
thermostat demand, the control locks o t nit operation.
IMPORTANT
If the control locks out, it can be reset by breaking
thermostat demand for about five seconds then re
making thermostat demand. Also, anytime thermo
stat demand is removed or power is interrupted, the
control resets to zero faults.
IMPORTANT
If the cycle counter counts three faults during the
same thermostat demand, the control locks out. The
outdoor unit remains inoperable until thermostat de
mand is broken. This indicates further troubleshoot
ing is needed. Though the control can be reset by
breaking thermostat demand, the unit may remain in
operable. The high pressure or low pressure condi
tions may still exist and must be located and cor
rected before the unit can be placed back in service.
See diagnostic codes to determine problem.
IMPORTANT
Intermittent continuity (bad connection or failing
components) can cause false lockout or lit diagnos
tic lights. Check electrical connections thoroughly.
A fault occurs when:
1- Com ressor o eration is monitored by high and low
ressure switches. These controls are wired in seĆ
ries. If either one tri s, com ressor o eration is
interru ted and one fault is counted. The control
locks out com ressor o eration for a minimum of
five minutes when a safety device terminates o eraĆ
tion. High ressure switch must be reset manually
but low ressure switch resets automatically.
It is likely that the control could count three unit
faults from the low ressure switch during a single
thermostat demand since this switch resets autoĆ
matically. However, the cycle counter can only
count unit faults from the high ressure switch if
the reset button is ushed without interru ting
thermostat demand.
2- On all units using the TSC twoĆs eed control, termiĆ
nals S1 and S2 on the control are connected to
tem erature sensors (thermistors) which monitor
the tem erature of the com ressor motor windings.
The twoĆs eed control measures the resistance
through the sensors. The sensors increase their reĆ
sistance as tem erature increases (for exam le, too
much su erheat). When the resistance through the
sensors increases above a reset limit, the control
sto s com ressor o eration for a minimum of five
minutes. As the com ressor windings cool, the reĆ
sistance through the sensors dro s below the
reset limit, the control resets automatically and
one fault is counted.

Page 10
Check sensors by measuring resistance (ohms)
through the sensors with the wires disconnected
from the control (unit not running). The sensor wires
are not olarity sensitive. Table 3 shows winding
tem erature sensor resistance values which will
cause the TSC to lock out. When unit is o erating
normally, resistance through the sensors should be
below the tri value shown in table 3.
TABLE 3
Compressor Winding
Temperat re Sensor
Trip Ohms
Temp. Rise
Reset Ohms
Temp. Fall
TSC5 Copeland Compressor 25K to 35K 8.4K to 10K
The control can be checked by com aring the reĆ
sistance measured through the sensors to the
voltage measured across the sensor terminals
with the unit running. Table 4 shows voltage meaĆ
sured across twoĆs eed control terminals S1 and
S2 with the com ressor running.
Reset
Range
TABLE 4
Resistance Thro gh
Compressor Winding
Temperat re Sensor
KĆohms (ohms x 1000)
Voltage Across TSC5
compressor sensor terminals
with Unit R nning DC Volts
0
1.0
5.5
6.9
8.4
10.0
16.0
20.0
24.0
25.0
30.0
35.0
Trip
Range
+-
DC volts
Measured with unit running.
COMPRESSOR WINDING SENSOR
OPERATING RANGE
0
1.70 - 1.82
6.07 - 6.48
6.86 - 7.33
7.55 - 8.07
8.16 - 8.72
9.69 - 10.36
10.34 - 11.05
10.82 - 11.57
10.93 - 11.68
11.35 - 12.14
11.68 - 12.48
MODE SELECTION JUMPERS
The control has six mode selection j mpers for selection of
operating modes and problem code recall or test. Choose
one of the first fo r modes for operation.
Normal: Normal operation (defa lt mode). Unit
r ns on high or low speed as the indoor
thermostat load demands.
Latch 1: After high speed demand is met, the nit
remains in high speed ntil the low speed
demand is satisfied.
Latch 2: After the nit operates in low speed for 15
min tes consec tively, it switches to high
speed ntil low speed demand is satisfied.
Latch 3: After the nit operates in low speed for 30
min tes consec tively, it switches to high
speed ntil low speed demand is satisfied.
Recall: Used in conj nction with the bypass
b tton to recall the stored problem codes.
Test: Used in conj nction with the control
b tton to start test mode.
Latch 2 or 3 modes are recommended in high h midity
areas. If the j mper falls off or is removed, the control will
contin e to operate in the previo sly set mode ntil the
control is reset d e to loss of power, then the control will
defa lt to the Normal mode. The latch feat re does not afĆ
fect the indoor blower operation.
TEST MODE
The control has a test mode. To initiate this mode, move
the j mper to the test position and p sh the control b tton.
The nit will operate in low speed for 10 seconds, t rn off
for ten seconds, then operate in high speed for 10 seĆ
conds. The control will only go into the test mode if there is
no thermostat demand and 5 min tes has elapsed since
the nit ran. The indoor blower does not r n d ring this
mode. The test mode cannot r n more than once every 5
min tes.
LED LIGHTS
Y1 and Y2 lights are connected directly to the inp ts from the
thermostat. They indicate low and high speed demand, reĆ
spectively.
The HI and LO lights are connected directly across the conĆ
tactor coils. They indicate if the high and low speed contactors
are energized.
The HEARTBEAT light is connected to the microcontroller
nit (MCU). It indicates when the control's MCU is operating
correctly, and also when the control is in delay mode. It blinks
at a rate of fo r times a second when the MCU is operating
properly and at a rate of once every two seconds when in the
delay mode (s ch as the 1 or 5 min te delay). If the LED is
contin o sly on or off (ass ming the power is on), the MCU is
not operating properly and the control needs to be replaced.
The D1, D2, D4, and D8 (see fig re 7) diagnostic lights disĆ
play diagnostic codes to aid in nit tro bleshooting. Refer to
Diagnostic Code Table (table 5).
Diagnostic Code Display
A problem code is normally displayed only for the d ration of
the error. There is one exception. D ring a locko t, the code
for the problem ca sing the locko t flashes once a second
even if the problem condition no longer exists. If other probĆ
lems occ r d ring a locko t condition, the codes for those
problems will be saved in memory, b t not displayed. The
stored problem codes are displayed by recalling them from
memory. The diagnostic codes can be reĆdisplayed by setting
the j mper to the recall position. The stored codes are disĆ
played by p shing the p sh b tton. As previo sly mentioned,
the p sh b tton is sed to bypass the fiveĆmin te delay and to
initiate the test mode. In addition, the b tton is sed to step
back thro gh the stored diagnostic codes and erase the diagĆ
nostic code memory. Diagnostic codes are recalled in the
reverse order of act al occ rrence. Each s bseq ent b tton

Page 11
p sh will display additional codes ntil the last one, which will
stay on with additional b tton p shes. Hold the b tton down
ntil the lights go off (approximately five seconds) to erase the
memory. The control has a nonvolatile memory that stores the
63 most recent diagnostic codes. These codes are stored in
memory, even in the event of a power loss.
Not all codes ca se locko ts or indicate problems. The p rĆ
pose of the diagnostic lights is to let the installer or service
technician know what is going on with the entire system, not
j st the two-speed control. Some codes do indicate malf ncĆ
tions or problems with either the control or the HS21, while
others inform the technician of the nit's stat s. All codes,
except for three, are stored in memory and may be recalled.
Code 1 - Power Loss for Two Electrical Cycles
This code indicates that the nit's power skipped two
electrical cycles (33-40 milliseconds). It may s ggest that
power to the nit is dirty" or is of low q ality. Code 1 is
stored.
Code 2 - Input Indication
This code indicates that a change has been made and
that the control acknowledges the change. It does not inĆ
dicate a problem condition. It indicates activity s ch as
j mper setting changes, delay overrides, or addition of an
optional safety device to Option 1 or 2. Code 2 is not
stored.
Code 3 - Unsteady Thermostat Input
Code 3 indicates intermittent inp ts from the room therĆ
mostat. Most likely, there is a loose connection at the
thermostat when this condition appears. Code 3 is
stored.
Code 4 - Pressure Switch Opens < Two Minutes
If the low or high press re switch opens after the compressor
has r n for less than two min tes, Code 4 will be displayed.
This may indicate blockage or fan fail re. Code 4 is stored. If
the nit still operates after code is displayed, the low press re
switch stops operation (low press re is a to-reset). Check for
low system charge.
Code 5 - Pressure Switch Opens > Two Minutes
If the low or high press re switch opens after the comĆ
pressor has r n for more than two min tes, Code 5 is
displayed. This may indicate an improper charge or coil
obstr ct ion. Code 5 is stored. If the nit still operates af ter
code is displayed, the low press re switch stops operaĆ
tion (low press re is a to-reset). Check for low system
charge.
TABLE 5
TSC5 DIAGNOSTICS CODES
CODE
CONDITION
DISPLAY LIGHTS
CODE
NUMBER CONDITION 8 4 2 1
1Power loss for two
cycles
OFF OFF OFF ON
2Inp t Indication OFF OFF ON OFF
3Unsteady Inp t OFF OFF ON ON
4Press re Switch Open
<2 min tes
OFF ON OFF OFF
5Press re Switch Open
> 2 min tes
OFF ON OFF ON
6Hot Compressor < 5
min. (or open sensor)
OFF ON ON OFF
7Hot Compressor > 5 min.
(or open sensor)
OFF ON ON ON
8Option 1 < 5 min tes ON OFF OFF OFF
9Option 1 > 5 min tes ON OFF OFF ON
10 Option 2 Open ON OFF ON OFF
11 O tdoor Temperat re
Sensor Problem
ON OFF ON ON
12 Not Used on TSC5 ON ON OFF OFF
13 Not Used ON ON OFF ON
14 Test Mode ON ON ON OFF
15 No J mper in place
Indication
ON ON ON ON
Code 6 - Hot Compressor < Five Minutes
Code 6 indicates the compressor temperat re exceeded
its limit after r nning less than five min tes. Code 6 is
stored.
Code 7 - Hot Compressor > Five Minutes
Code 7 indicates the compressor temperat re exceeded
its limit after r nning more than five min tes. Code 7 is
stored.
Code 8 - Option 1 < Five Minutes
Code 8 occ rs if the Option 1 safety device switch opens
after the compressor r ns less than five min tes. Code 8 is
stored.
Code 9 - Option 1 > Five Minutes
Code 9 occ rs if the Option 1 safety device switch opens afĆ
ter the compressor r ns more than five min tes. Code 9 is
stored.
Code 10 - Option 2
Code 10 is displayed if the Option 2 safety device switch
opens. Code 10 is stored.

Page 12
Code 11 - Compressor Temperature Sensor Shorted
This code indicates that the compressor temperat re sensor
wires have shorted together. Code 11 is stored.
Code 12 - Not used on TSC5
This code does not pertain to the two-speed control (TSC5)
sed on condensing nits.
Code 13 - Not Used
This code may be sed in f t re models of the two-speed
control, b t at this time has no f nction and, therefore, is not
stored.
Code 14 - Test Mode
Code 14 does not indicate a problem. The control is in TEST
mode when this code is displayed. See Mode J mper SelecĆ
tions section.
Code 15 - No Jumper in Place
Code 15 is displayed when the mode j mper is not in place.
Make s re j mper is placed sec rely across the selected set
of pins for the appropriate mode of operation.
SERVICE RELAY
The control has a b iltĆin service relay. This relay controls
the thermostat service light or comm nicates with an alarm
device. The relay signals the alarm device in s ch a manner
that the alarm device can disting ish between a locko t and
a nonĆlocko t condition. The relay contacts are normally
open when no problems or locko t conditions occ r. A nonĆ
locko t condition is reported by closing the contacts for the
d ration of the next noĆdemand period. If the control goes
into a locko t state, the relay will close and remain closed
ntil the next loss of demand. If the service light on the room
thermostat is connected to the service relay, the light will
t rn on if the control is in a locko t. It will not t rn on if the
control is detecting nonĆlocko t problems. In order for the
service relay to indicate only a locko t condition, one side of
the relay m st be wired to the alarm and the other side to
Y2. D ring a sim ltaneo s Y1 and Y2 demand with a nonĆ
locko t condition, the alarm will energize for a very short
d ration (.2 seconds). If both an alarm device and thermoĆ
stat service lights are sed, an additional external relay may
be req ired depending on the thermostat sed.
OPTIONAL INPUTS
The control has two optional inp ts for additional protection
devices. If options 1 or 2 are going to be sed, move the three
pin miniĆj mper to the YES side. OPT 1 inp t will lock o t the
compressor on the third co nt. OPT 2 inp t will not lock o t
the compressor at any time, b t will display and store the
problem code (see Diagnostic code Table). These inp ts are
designed for normally closed switches connected to 24VAC.
CAUTION
Do not remove the jumpers unless additional
protection controls are going to be installed. If OPT
1 jumper is not connected to the NO pin, the control
will lock out the compressor. If OPT 2 is not con
nected to the NO pin, the display only shows the
problem code.
IV-REFRIGERANT SYSTEM
A-Plumbing
Field refrigerant piping consists of liq id and s ction lines from
the indoor coil to the o tdoor nit (sweat connections). Use
Lennox L10 series line sets as shown in table 6 or field fabriĆ
cated refrigerant lines. Install filter drier, provided with nit, in
the liq id line as close as possible to the expansion device.
MODEL NO. LIQUID VAPOR L10
LINE LINE LINE SETS
HS21Ć410
HS21-036 3/8 in. 3/4 in. L10Ć41
20 ft. Ć 50 ft.
HS21Ć510
HS21-048 3/8 in. 7/8 in. L10Ć65
30 ft. Ć 50 ft.
HS21Ć650
HS21-060 3/8 in. 1Ć1/8 in. FIELD
FABRICATED
TABLE 6
B-Discharge Muffler
All nits are eq ipped with a discharge m ffler located in the
discharge line of the compressor. The m ffler atten ates disĆ
charge gas p lsations from the compressor to lower so nd
levels. The discharge m ffler is located immediately in front of
the compressor in the compressor compartment. See fig re 1
or 2.
C-Thermometer Well
All nits are eq ipped with a thermometer well for se in meaĆ
s ring liq id line temperat re when charging the nit. The
thermometer well is sed in all Lennox recommended chargĆ
ing proced res. It is located in the liq id line adjacent to the
liq id line service valve.
D-Service Valves
The liq id line and s ction line service valves and ga ge ports
are accessible by removing the compressor access cover.
F ll service liq id and s ction line valves are sed. See figĆ
res 9 and 11. The service ports are sed for leak testing,
evac ating, charging and checking charge.

Page 13
1-Liquid Line Service Valve
A f llĆservice liq id line valve made by one of several
man fact rers may be sed. All liq id line service valves
f nction the same way, differences are in constr ction. Valves
man fact red by Parker are forged assemblies. Valves
man fact red by Primore are brazed together. Valves are not
reb ildable. If a valve has failed it m st be replaced. The liq id
line service valve for HS21-411, -511, and -060 is ill strated
in fig re 9. The liq id line service valve for HS21-036, -048
and -060 is ill strated in fig re 10.
The valve is eq ipped with a service port. There is no schradĆ
er valve installed in the liq id line service port. A service port
cap is s pplied to seal off the port.
The liq id line service valve is a front and back seating valve.
When the valve is backseated the service port is not press rĆ
ized. The service port cap can be removed and ga ge
connections can be made.
CAUTION
A schrader valve is not provided on the liquid line
service port. The service port cap is used to seal the
liquid line on the service valve. Access to service
port requires backseating the service valve to isolate
the service port from the system. Failure to do so will
cause refrigerant leakage.
KNIFE EDGE SEAL
STEM
CAP
SERVICE
PORT CAP
TO
LINE
SET
TO CONDENSER
COIL
LIQUID LINE SERVICE VALVE
HS21-411, -511, -651
IMPORTANT
A schrader valve is not
provided on the liquid
line service port. Valve
must be backseated to
turn off pressure to
service port.
FIGURE 9
VALVE STEM
USE SERVICE
WRENCH
(PART #18P66,
54B64 or 12P95)
SERVICE PORT OPEN
TO LINE SET WHEN
FRONT SEATED AND
CLOSED (OFF) WHEN
BACK SEATED
NO SCHRADER
To Access Service Port:
1- Remove the stem cap. Use a service wrench
to make s re the service valve is backseated.
2- Remove service port cap and connect high press re
ga ge to service port.
3- Using service wrench, open valve stem (one t rn clockĆ
wise) from backseated position.
4- When finished sing port, backseat stem with service
wrench. Tighten firmly.
5- Replace service port and stem cap. Tighten finger tight,
then tighten an additional 1/6 t rn.
To Close Off Service Port:
1- Using service wrench, backseat valve.
a-Turn stem counterclockwise.
b-Tighten firmly.
To Open Liquid Line Service Valve:
1- Remove the stem cap with an adj stable wrench.
2- Using service wrench, backseat valve.
a-Turn stem counterclockwise until backseated.
b-Tighten firmly.
3- Replace stem cap, finger tighten then tighten an addiĆ
tional 1/6 t rn.
To Close Liquid Line Service Valve:
1- Remove the stem cap with an adj stable wrench.
2- T rn the stem in clockwise with a service wrench to
front seat the valve. Tighten firmly.
3- Replace stem cap, finger tighten then tighten an addiĆ
tional 1/6 t rn.
2-Suction Line (Seating Type) Service Valve
A f ll service nonĆbackseating s ction line service valve is
sed on all HS21 series nits. Different man fact rers of
valves may be sed. All s ction line service valves f nction
the same way, differences are in constr ction.
Valves man fact red by Parker are forged assemblies.
Primore and Aeroq ip valves are brazed together. Valves
are not reb ildable. If a valve has failed it m st be reĆ
placed. The s ction line service valve for HS21-411, -511
and -060 is ill strated in fig re 11. The s ction line service
valve for HS21-036, -048 and -060 is ill strated in fig re
12.
The valve is eq ipped with a service port. A schrader valve
is factory installed. A service port cap is s pplied to protect
the schrader valve from contamination and ass re a leak
free seal.
To Access Schrader Valve:
1- Remove service port cap with an adj stable wrench.
2- Connect ga ge to the service port.
3- When testing is completed, replace service port cap.
Tighten finger tight, then an additional 1/6 t rn.
To Open Suction Line Service Valve:
1- Remove stem cap with an adj stable wrench.
2- Using service wrench and 5/16" hex head extension
back the stem o t co nterclockwise ntil the valve stem
j st to ches the retaining ring.
3- Replace stem cap tighten firmly. Tighten finger tight,
then tighten an additional 1/6 t rn.

Page 14
FIGURE 10
LIQUID LINE SERVICE VALVE
HS21-036, -048, -060
SERVICE
PORT
SERVICE
PORT
CAP
INLET (TO
INDOOR COIL)
STEM CAP
SCHRADER VALVE
OUTLET TO
COMPRESSOR
(VALVE OPEN)
VALVE OPEN
FIGURE 11
SCHRADER VALVE
SERVICE PORT
SERVICE
PORT
CAP
STEM CAP
SNAP RING
INSERT HEX WRENCH
HERE (PART #49A71 AND
SERVICE WRENCH)
INLET
(FROM INDOOR COIL)
OUTLET
(TO COMPRESSOR)
KNIFE
EDGE
SEAL
SUCTION LINE SERVICE VALVE
HS21-411, -511, -651
SUCTION LINE (BALL TYPE) SERVICE VALVE
SCHRADER
VALVE
STEM CAP
BALL
(SHOWN OPEN)
SERVICE PORT
CAP
SERVICE
PORT
FIELD SIDE
UNIT SIDE
STEM
FIGURE 12
HS21-036, -048, -060
(VALVE OPEN)
Do not attempt to backseat this valve. Attempts to
backseat this valve will cause snap ring to explode
from valve body under pressure of refrigerant.
Personal injury and unit damage will result.
DANGER
To Close Suction Line Service Valve:
1- Remove stem cap with an adj stable wrench.
2- Use service wrench and 5/16" hex head extension t rn
stem clockwise to seat the valve. Tighten firmly.
3- Replace stem cap. Tighten finger tight, then tighten an
additional 1/6 t rn.
V-CHARGING
The nit is factoryĆcharged with the amo nt of HCFCĆ22
refrigerant indicated on the nit rating plate. This
charge, as shown in the specification table on page 1, is
based on a matching indoor coil and o tdoor coil with 20
feet of line set.
For varying lengths of line set, refer to table7 for refrigerant
charge adj stment. A blank space is provided on the nit ratĆ
ing plate to list act al field charge.
LIQUID LINE
1/4 in. (6 mm)
5/16 in. (8mm)
3/8 in. (10 mm)
TABLE 7
Ounce per 5 foot (ml per mm) adjust
from 20 foot (6096 mm) line set*
1 o nce per 5 feet (30 ml per 1524 mm)
*If line set is greater than 20 ft. (6.09m) add this amount. If line set
is less than 20 feet (6.09m) subtract this amount
SET DIAMETER
2 o nce per 5 feet (60 ml per 1524 mm)
3 o nce per 5 feet (90 ml per 1524 mm)
Units are designed for line sets p to 50 ft. Cons lt LenĆ
nox Refrigerant Piping Man al (Corp. 9351ĆL9) for line
sets over 50 ft.
A-Leak Testing
1Ć Attach ga ge manifold and connect a dr m of dry nitroĆ
gen to center port of ga ge manifold.
2Ć Add a small amo nt of refrigerant to the lines and
coil. Open high press re valve on ga ge manifold.
Press rize line set and indoor coil to 150 psig (1034
kPa).
WARNING
Danger of Explosion.
Can cause injury, death and equipment
damage.
When using dry nitrogen, use a pres
sure reducing regulator, set at 150 psig
(1034 kPa) or less to prevent excessive
pressure.
3Ć Check lines and connections for leaks.
NOTEĆIf electronic leak detector is used, add a trace of reĆ
frigerant to nitrogen for detection by leak detector.
4Ć Release nitrogen press re from the system, correct any
leaks and recheck.

Page 15
B-Evacuating the System
Evac ating the system of nonĆcondensables is critical for
proper operation of the nit. NonĆcondensables are deĆ
fined as any gas that will not condense nder
temperat res and press res present d ring operation of
an air conditioning system. NonĆcondensables s ch as
water vapor, can combine with refrigerant to prod ce s bĆ
stances that corrode copper piping and compressor parts.
1Ć Attach ga ge manifold and connect vac m p mp
(with vac m ga ge) to center port of ga ge manifold.
With both ga ge manifold service valves open, start
p mp and evac ate evaporator and refrigerant lines.
IMPORTANT
A temperature vacuum gauge, mercury vacuum
(U tube), or thermocouple gauge should be used.
The usual Bourdon tube gauges are not accurate
enough in the vacuum range.
IMPORTANT
The compressor should never be used to evacu
ate a refrigeration or air conditioning system.
CAUTION
Danger of Equipment Damage. Avoid deep vacuum
operation. Do not use compressors to evacuate a
system. Extremely low vacuums can cause internal
arcing and compressor failure. Damage caused by
deep vacuum operation will void warranty.
2Ć Evac ate system to absolute press re of .92 inches of
merc ry, 23 mm of merc ry, or 23,000 microns.
3Ć After system has been evac ated to an absol te presĆ
s re of .92 inches merc ry, 23 mm merc ry, or 23,000
microns, close manifold valve to center port.
4Ć Stop vac m p mp and disconnect from ga ge manĆ
ifold. Attach a tank of dry nitrogen to center port of ga ge
manifold sing a nitrogen reg lator. Open tank valve
slightly to p rge line, then break vac m in system to 3
psig (20.7 kPa) press re by opening manifold high presĆ
s re valve to center port.
5Ć Close nitrogen valve, disconnect tank from manifold
center port and release nitrogen from system.
6Ć Reconnect vac m p mp to manifold center port hose.
Evac ate the system to an absol te press re less than
.0197 inches of merc ry, .500 mm of merc ry, or 500 miĆ
crons, then t rn off vac m p mp. If the absol te
press re rises above .0197 inches of merc ry, .500 mm
of merc ry, or 500 microns within a 20Ćmin te period afĆ
ter stopping vac m p mp, repeat step 6. If not,
evac ation is complete.
This evac ation proced re is adeq ate for a new instalĆ
lation with clean and dry lines. If excessive moist re is
present, the evac ation process may be req ired more
than once.
7Ć After evac ation has been completed, close ga ge
manifold service valves. Disconnect vac m p mp
from manifold center port and connect refrigerant
dr m. Press rize system slightly with refrigerant to
break vac m.
C-Charging
The following proced res are intended as a general g ide for
se with expansion valve systems only. For best res lts, inĆ
door temperat re sho ld be between 70 °F and 80 °F.
O tdoor temperat re sho ld be 60 °F or above. Slight variaĆ
tions in charging temperat re and press re sho ld be
expected. Large variations may indicate a need for f rther
servicing.
If the system is completely void of refrigerant, the recomĆ
mended and most acc rate method of charging is to weigh
the refrigerant into the nit according to the total amo nt
shown on the nit nameplate.
If weighing facilities are not available or if nit is j st low on
charge, the following proced re applies.
APPROACH METHOD (TXV SYSTEMS)
(Ambient Temperature of 60_F [16_C] or Above)
1- Connect ga ge manifold. Connect an pright HCFCĆ22
dr m to center port of ga ge manifold.
IMPORTANT
The following procedure requires accurate read
ings of ambient (outdoor) temperature, liquid tem
perature and liquid pressure for proper charging.
Use a thermometer with accuracy of +2 °F and a
pressure gauge with accuracy of +5 PSIG.
2- Record o tdoor air (ambient) temperat re.
3- Operate indoor and o tdoor nits in cooling mode. Allow
nits to r n ntil system press res stabilize.
4- Make s re thermometer well is filled with mineral oil beĆ
fore checking liq id line temperat re.
5- Place thermometer in well and read liq id line temperaĆ
t re. Liq id line temperat re sho ld be a few degrees
warmer than the o tdoor air temperat re. Tables 8 (earĆ
ly models) and 9 (late models) show how many degrees
warmer the liq id line temperat re sho ld be.
Add refrigerant to make the liq id line cooler.
Recover refrigerant to make the liq id line warmer.
TABLE 8
Model
HS21Ć511/513
HS21Ć651/653
APPROACH METHOD EXPANSION VALVE SYSTEMS
4+1
3+1
HS21Ć411/413 4+1
Liquid Line °F Warmer Than Outside
(Ambient) Temperature
TABLE 9
Model
HS21Ć048
HS21Ć060
APPROACH METHOD EXPANSION VALVE SYSTEMS
7+1
8+1
HS21Ć036
Liquid Line °F Warmer Than Outside
(Ambient) Temperature
7+1
6- When nit is properly charged liq id and s ction line
press res sho ld approximate those in tables 10 or 11.

Page 16
IMPORTANT
Use tables10 or 11 as a general guide for performing
maintenance checks. Tables 10 and 11 are not a pro
cedure for charging the system. Minor variations in
these pressures may be expected due to differences
in installations. Significant deviations could mean
that the system is not properly charged or that a
problem exists with some component in the system.
Used prudently, tables 10 and 11could serve as a
useful service guide.
TABLE 10
NORMAL OPERATING PRESSURES HIGH SPEED OPERATION
OUTDOOR COIL
ENTERING AIR
TEMPERATURE
HS21 510 HS21 650
65° F (TXV)
75°F (TXV)
85°F (TXV)
95°F (TXV)
LIQ.
+ 10
SUC.
+ 10
PSIG PSIG
LIQ.
+ 10
SUC.
+ 10
PSIG PSIG
105°F (TXV)
HS21 410
SUC.
+ 10
PSIG
LIQ.
+ 10
PSIG
149
173
202
232
265
72
74
76
79
81
160
185
220
255
285
73
76
78
80
82
138
165
192
223
257
69
72
74
76
78
TABLE 11
NORMAL OPERATING PRESSURES HIGH SPEED OPERATION
OUTDOOR COIL
ENTERING AIR
TEMPERATURE
HS21 048 HS21 060
65° F (TXV)
75°F (TXV)
85°F (TXV)
95°F (TXV)
LIQ.
+ 10
SUC.
+ 10
PSIG PSIG
LIQ.
+ 10
SUC.
+ 10
PSIG PSIG
105°F (TXV)
HS21 036
SUC.
+ 10
PSIG
LIQ.
+ 10
PSIG
149
173
202
218
265
72
74
76
78
79
142
168
196
227
260
72
74
76
77
79
142
173
202
238
267
70
75
77
78
80
D-Oil Charge
Factory oil charge in all HS21 series nits is 70 fl. oz. S niso
3GS.
VI-MAINTENANCE
At the beginning of each heating or cooling season, the sysĆ
tem sho ld be cleaned as follows:
A-Outdoor Unit
1- Clean and inspect condenser coil. (Coil may be fl shed
with a water hose).
2- Vis ally inspect all connecting lines, joints and coils for
evidence of oil leaks.
IMPORTANT
If insufficient cooling occurs, the unit should be
gauged and refrigerant charge checked.
B-Indoor Coil
1- Clean coil if necessary.
2- Check connecting lines and coil for oil leaks.
3- Check condensate line and clean if necessary.
C-Indoor Unit
1- Clean or change filters.
2- Adj st blower cooling speed. Check static press re drop
over coil to determine correct blower CFM. Refer to LenĆ
nox Engineering Handbook.
3- Belt Drive BlowersĂĆĂCheck condition/tension.
4- Check all wiring for loose connections.
5- Check for correct voltage at nit.
6- Check ampĆdraw on blower motor.
Unit nameplate_________Act al_________.
VII-Miscellaneous
If the fan orifice sho ld ever need to be removed for service,
make s re the control box seals watertight before placing the
nit back in service. Fig re 13 shows the components sed
to make the control box watertight. Two screws sec ring the
top of the control box to the cabinet m st have r bber washĆ
ers installed. Also, the control box m st be installed with a
foamĆr bber weatherstrip installed along the top edge (beĆ
tween the control box and the cabinet).
HS21 CONTROL BOX WEATHERPROOFING
WEATHERSTRIPPING BETWEEN
CONTROL BOX AND FAN ORIFICE
PANEL. USED TO PREVENT FAN
FROM THROWING WATER INTO
CONTROL BOX.
SCREWS WITH RUBBER WASHĆ
ERS. WASHERS PREVENT WATER
FROM DRIPPING INTO CONTROL
AREA. MAKE SURE WASHERS ARE
IN GOOD CONDITION AND MAKE
SURE SCREWS SEAT SECURELY
AND ARE NOT CROSSĆTHREADED.
FIGURE 13

Page 17
VIII-Operation Sequence Compressor
Single Phase Compressor Start Up
Fig re 14 shows singleĆphase compressor windings.
This compressor has a two speed capacitorĆstart, capacĆ
itorĆr n motor. For starting, the start and r n capacitors
are in parallel to provide the proper starting torq e. The
start capacitor is disconnected by the start relay when the
compressor comes p to speed. The r n capacitor reĆ
mains connected to the start winding and the motor r ns
as a twoĆphase ind ction motor with improved power facĆ
tor and torq e characteristics provided by the capacitor.
Low speed compressor operation is provided by powering
the r n windings (internally connected in series) from termiĆ
nals 1 (common) and 7. The windings form a fo rĆpole motor
operating at 1800 RPM. The fo r low speed start windings
are in series and are connected to terminals 1 (common) and
8. They are sed with the start and r n capacitors and start
relay to start and bring the motor p to speed.
High speed compressor operation is provided when the r n
windings are connected in parallel; terminals 1 (common)
and 7 to L1 and terminal 2 to L2. The windings form a twoĆ
pole motor operating at 3600 RPM. The two high speed start
windings are in series and are connected to terminals 1
(common) and 3.
Three Phase Compressor Start Up
Fig re 15 shows the windings of threeĆphase twoĆspeed
compressors. The compressors have twoĆspeed, threeĆ
phase ind ction motors. Capacitors are not needed to
provide the proper phase and torq e characteristics.
Low speed operation is provided when the motor windings
are connected in a series Delta" circ it. The motor operates
at 1800 RPM.
High speed operation is provided when the motor windings
are connected in a parallel Delta" circ it. Normally closed
contacts on the low speed contactor provide this connecĆ
tion. The motor operates at 3600 RPM.
FIGURE 14
MOTOR LEAD TERMINALS
LOW SPEED
START WINDINGS
HIGH SPEED
START WINDINGS
COMMON
RUN WINDINGS
RUN
CAP.
START
CAP.
START RELAY
8
3
7
2
1
MOTOR LEAD TERMINALS
COMMON
8
3
7
2
1
HIGH SPEED
START WINDINGS
RUN WINDINGS
LOW SPEED
START WINDINGS
START RELAY
START
CAP.
RUN
CAP.
SINGLE PHASE MOTOR WINDINGS LOW SPEED
SINGLE PHASE MOTOR WINDINGS HIGH SPEED
FIGURE 15
THREE PHASE MOTOR WINDINGS LOW SPEED
SERIES DELTA" CIRCUIT
THREE PHASE MOTOR WINDINGS HIGH SPEED
PARALLEL DELTA" CIRCUIT
L1
L2
L3
T1
T4
T3
T5
T2
T6
L1
L2
L3
T4
T3
T5T2T6
T1
COMPRESSOR
CONTACTOR K1Ć1

Page 18
IX - WIRING DIAGRAMS AND SEQUENCE OF OPERATION
HS21 SINGLE PHASE
-036, -048, 060

Page 19
5
6
7
8
9
10
11
12
13
15
1
2
3
4
14
16
17
18
19
20
21
22
23
24
4
HS21 SINGLE PHASE -411, -511, -651

Page 20
HS21 SINGLE PHASE UNITS
Electromechanical Thermostat Connected to HS21-411,511,651,036,048,060
SINGLE PHASE STARTING SEQUENCE:
1- Line voltage feeds thro gh L1 and L2 to energize o tdoor transformer T19 and o tdoor
nit. Crankcase heater is energized thro gh relay K1 a xiliary contacts.
2- Transformer T19 provides 24VAC to TSC (A14) and contactors K1 and K69.
3- The indoor transformer s pplies 24VAC to the indoor nit and the indoor thermoĆ
stat.
4- On powerĆ p, 24VAC is fed thro gh JP44Ć1 and JP44Ć7 to the TSC. The TSC beĆ
gins a 10 second powerĆ p delay.
5- The TSC begins a 5 min te delay d ring which the o tdoor nit is not operational.
After a 5 min te delay, the TSC waits in OFF" mode for 1st stage or 2nd stage
demand.
SINGLE PHASE COMPRESSOR START UP:
Low Speed
6- 1st stage demand: If all safety circ its check o t, TSC energizes JP44Ć9.
7- Contactor K1 is energized thro gh K69Ć2 N.C. contacts. K1Ć2 contacts open to
de-energize the crankcase heater. All other K1 contacts close to start o tdoor fan
operation and to begin compressor low speed startĆ p.
8- Compressor B1 terminal 1 and the o tdoor fan circ it are energized by K1 conĆ
tacts L1ĆT1. Compressor terminal 7 is energized by contactor K1 terminal L2ĆT2
thro gh contactor K69 terminal T1ĆX1. Compressor terminal 8 (start winding) is
energized by contactor K1 terminal L2ĆT2 thro gh the start (C7) and r n (C5) caĆ
pacitors and contactor K69 terminal T3ĆX3.
9- O tdoor fan B4 is energized when contactor K1 contacts L1ĆT1 and L2ĆT2 close.
10-As the compressor nears f ll speed, potential relay K31 energizes and K31 conĆ
tacts open to deĆenergize the start capacitor.
High Speed
11-2nd stage demand: If all safety circ its check o t, TSC energizes JP44Ć8.
12-Contactor K69 energizes and K69Ć2 a xiliary contacts close to energize contactor
K1. K1Ć2 a xiliary contacts open to deĆenergize the crankcase heater. All other K1
contacts close. K69 contacts L1ĆT1, L2ĆT2 and L3ĆT3 close while contacts T1ĆX1
and T3ĆX3 open.
13-Compressor B1 terminal 3 (start winding) is energized by contactor K1 terminal
L2ĆT2 thro gh the start (C7) and the d al (C12) capacitors and thro gh contactor
K69 terminal L3ĆT3. Compressor terminal 2 is energized by contactor K1 terminal
L2ĆT2, and contactor K69 terminal L2ĆT2. Compressor terminal 1 is energized diĆ
rectly by contactor K1 terminal L1ĆT1. Compressor terminal 7 is energized by conĆ
tactor K1 terminal L1ĆT1 and thro gh contactor K69 terminal L1ĆT1.
14-O tdoor fan B4 is energized when contactor K1 contacts L1ĆT1 and L2ĆT2 close.
15-As the compressor nears f ll speed, potential relay K31 energizes and K31 conĆ
tacts open to deĆenergize start capacitor C7.
SINGLE PHASE COOLING SEQUENCE:
16-1st stage cooling demand energizes TB15ĆY1. TB15ĆY1 energizes TSC terminal
JP44Ć6.
NOTEĆ2nd stage cooling demand may be energized directly without assing
through 1st stage.
17-TSC delays 3 seconds before responding to the new command.
18-If the nit is changing from 2nd stage to 1st stage demand, TSC initiates speed
change delay and deĆenergizes JP44Ć8 and JP44Ć9 to stop all nit operation for
60+5 seconds. After TSC completes the 60+5 second speed change delay or if
the nit is starting p in 1st stage directly from OFF mode, TSC checks safety cirĆ
c its by looking for 24VAC at JP44Ć7 and by checking resistance thro gh wires
connected to S1 and S2.
19-If all safety circ its check o t, TSC energizes K1 and compressor begins low
speed startĆ p.
20-2nd stage cooling demand energizes TB15ĆY1 and TB15ĆY2. TB15ĆY2 energizes
TSC terminal JP44Ć4. TB15ĆY1 energizes TSC terminal JP44Ć6.
21-TSC delays 3 seconds before responding.
22-If the nit is changing from 1st stage to 2nd stage demand, the TSC initiates
speed change delay and deĆenergizes JP44Ć8 and JP44Ć9 to stop all nit opĆ
eration for 60+5 seconds. After TSC completes the 60+5 second speed
change delay or if the nit is starting p in 2nd stage directly from OFF mode,
TSC checks safety circ its by looking for 24VAC at JP44Ć7 and by checking
resistance thro gh wires connected to S1 and S2.
23-If all safety circ its check o t, TSC energizes K1 and K69. Compressor begins
high speed startĆ p.
24-When thermostat demand is satisfied or if thermostat is switched OFF, all o tdoor
nit operation stops after a delay of 3 seconds. TSC then starts a 5 min te timedĆ
off delay.