INSTALLATION
2000 Lennox Industries Inc.
Dallas, Texas, USA
HS27 Outdoor Unit
HS27 outdoor units are designed for expansion valve systems only. They are not designed for RFC systems. Refer to
Lennox engineering handbook for expansion valve kits
which must be ordered separately.
Shipping & Packing List
1 − Assembled HS27 outdoor unit
2 − Grommets (for liquid and vapor lines)
1 − Bushing (for low voltage wiring)
Check equipment for shipping damage. If you find any
damage, immediately contact the last carrier.
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, personal injury or loss of life. Installation and service must
be performed by a qualified installer or service
agency.
IMPORTANT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFC’s and HCFC’s) as of July 1,
1992. Approved methods of recovery, recycling or
reclaiming must be followed. Fines and/or incarceration may be levied for noncompliance.
INSTRUCTIONS
HS27 SERIES UNITS
CONDENSING UNITS
504,669M
02/04
Supersedes 12/02
Table of Contents
HS27 Outdoor Unit 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping & Packing List 1. . . . . . . . . . . . . . . . . . . . . . . . .
General Information 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Dimensions 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Arrangement 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting the Unit 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Refrigerant Piping 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Refrigerant Metering Device 9. . . . . . . . . . . . . . . . . . . . .
Manifold Gauge Set 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Valves 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Leak Testing 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Evacuation 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Start−Up 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Charging 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Operation 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional Accessories 14. . . . . . . . . . . . . . . . . . . . . . . . . .
Start−up & Performance Check List 15. . . . . . . . . . . . . . .
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE
General Information
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
WARNING
This product and/or the indoor unit it is matched with
may contain fiberglass wool.
Disturbing the insulation during installation, maintenance, or repair will expose you to fiberglass wool
dust. Breathing this may cause lung cancer. (Fiberglass wool is known to the State of California to
cause cancer.)
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact your
supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379−9900
Litho U.S.A.
02/04
*2P0204*
Page 1
504,669M
*P504669M*
Unit Dimensions − inches (mm)
HS27-024
HS27-036
airinlet
inlet
COMPRESSOR
air
2
(51)
3-7/8
(98)
32-1/8 (816)
7-1/2
(191)
4-7/8 (22)
28-1/8 (714)
HS27-024
HS27-030
HS27-036
HS27-042
7-1/2
(191)
electrical
3-7/8
(98)
(51)
inlets
vapor line
inlet
A
liquid
line inlet
4-1/2 (114)
B
2-3/4 (70)
2
1-3/8
(35)
DISCHARGE AIR
2-9/16
(65)
4
(102)
Top View
34-1/16 (865)
18-5/8
(473)
26-5/8 (676)
Side ViewAccess View
Model No. A B
in. 30-7/8 12-3/4
mm 784 324
in. 40-7/8 19-3/4
mm 1038 502
airinlet
4
(102)
6-1/16
(154)
Page 2
Parts Arrangement
outdoor fan
(not shown)
top of cabinet
run capacitor
ground lug
contactor
terminal box
high pressure
switch
Figure 1
Setting the Unit
CAUTION
In order to avoid injury, take proper precaution when
lifting heavy objects.
CAUTION
Danger of sharp metallic edges. Can cause injury.
Take care when servicing unit to avoid accidental
contact with sharp edges.
Refer to unit dimensions for sizing mounting slab, platforms, or supports. Refer to figure 2 for installation clearances.
vapor valve
and gauge port
liquid line
service valve
and gauge port
compressor
low pressure
switch
Installation Clearances
NOTE − A service access
clearance of 30" (762 mm)
must be maintained in front
of the service access panel.
Clearance to one side must
be 36" (914 mm). Clearance
to one of the remaining two
sides may be 12" (304 mm)
and the final side may be 6"
(152 mm).
NOTE − A clearance of 24" (610 mm)
must be maintained between two units.
NOTE − 48" (1219 mm) clearance required on top
of unit. Maximum soffit overhang is 36" (914 mm).
36"
(914 mm)
*36"
(914 mm)
*36"
(914 mm)
36"
(914 mm)
Figure 2
Page 3
A − Slab Mounting
When you install the unit at grade level, the top of the slab
should be high enough above the grade so that water from
higher ground will not collect around the unit. See figure 3.
Slab should have a slope tolerance away from the building
of 2 degrees or 2 inches per 5 feet (51 mm per 1.5 m).
Refer to the furnace or blower coil installation instructions
for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.
WARNING
2 degrees or
2 in. per 5 foot
(51 mm per 1.5 m)
slope tolerance away
from building structure
ground level
Slab Mounting
discharge air
building
structure
mounting
slab
Figure 3
B − Roof Mounting
Install unit at a minimum of 4 inches above surface of the roof.
Care must be taken to ensure weight of unit is properly distributed over roof joists and rafters. Either redwood or steel supports are recommended.
Electrical
In the U.S.A., wiring must conform with current local codes
and the current National Electric Code (NEC). In Canada,
wiring must conform with current local codes and the current
Canadian Electrical Code (CEC).
Unit must be grounded in accordance with
national and local codes.
Electric Shock Hazard.
Can cause injury or death.
1. Install line voltage power supply to unit from a properly
sized disconnect switch.
2. Ground unit at unit disconnect switch or to an earth
ground.
NOTE − To facilitate conduit, a hole is in the bottom of
the control box. Connect conduit to the control box us
ing a proper conduit fitting.
NOTE − Units are approved for use only with copper
conductors.
24V, Class II circuit connections are made in the low
voltage junction box. Refer to figure 4 for field wiring
diagram.
NOTE − A complete unit wiring diagram is located in
side the unit control box cover.
3. Install room thermostat (ordered separately) on an inside wall approximately in the center of the conditioned
area and 5 feet (1.5 m) from the floor. It should not be
installed on an outside wall or where it can be effected
by sunlight, drafts or vibrations.
4. Install low voltage wiring from outdoor to indoor unit
and from thermostat to indoor unit. See figure 5.
Page 4
(LEADLESS)
Outdoor Unit
Field Wiring Diagram
YELLOW
Thermostat Designations
Thermostat Furnace
R
W1
Y
G
C
power
heat
cooling
indoor blower
common
R
W
Y
G
C
Figure 4
NOTE − see unit wiring diagram for
power supply connections.
Outdoor Unit
Y1 Outdoor Unit
C Outdoor Unit
NOTE − If the indoor unit is not equipped with blower relay, it must be field−provided and installed (P−8−3251 or equivalent).
Figure 5
Page 5
Refrigerant Piping
Field refrigerant piping consists of liquid and vapor lines
from the outdoor unit (sweat connections) to the indoor coil
(flare or sweat connections). Use Lennox L15 (sweat, nonflare) series line sets as shown in table 1 or use field-fabricated refrigerant lines. Refer to Refrigerant Piping Guide
(Corp. 9351−L9) for proper size, type, and application of
field−fabricated lines. Valve sizes are also listed in table 1.
Installing Refrigerant Line
During the installation of any heat pump or a/c system, it is
important to properly isolate the refrigerant lines to prevent
unnecessary vibration. Line set contact with the structure
(wall, ceiling or floor) causes some objectionable noise
when vibration is translated into sound. As a result, more
energy or vibration can be expected. Closer attention to
line set isolation must be observed.
Table 1
Refrigerant Line Sets
Field Valve Size
Connections
HS27
−024
−030
−036
−042
Liquid
Line
3/8 in
(10 mm)
3/8 in
(10 mm)
Vapor
Line
3/4 in.
(19 mm)
7/8 in.
(22 mm)
NOTE − Units are designed for line sets of up to 50 feet (15
m). For applications longer than 50 feet, consult the Lennox Refrigerant Piping Guide (Corp. 9351−L9). Select line
set diameters from table 1 to ensure that oil returns to the
compressor.
Recommended Line Set
Liquid
Line
3/8 in
(10 mm)
3/8 in
(10 mm)
Vapor
Line
3/4 in.
(19 mm)
7/8 in.
(22 mm)
L15
Line Sets
L15−41
15 ft. − 50 ft.
(4.6 m − 15 m)
L15−65
15 ft. − 50 ft.
(4.6 m − 15 m)
Following are some points to consider when placing and
installing a high−efficiency outdoor unit:
1- Placement − Be aware some localities are adopting
sound ordinances based on how noisy the unit is from
the adjacent property not at the original installation.
Install the unit as far as possible from the property line.
When possible, do not install the unit directly outside a
window. Glass has a very high level of sound transmission.
2- Line Set Isolation − The following illustrations demon-
strate procedures which ensure proper refrigerant line
set isolation. Figure 6 shows how to install line sets on
vertical runs. Figure 7 shows how to install line sets on
horizontal runs. Figure 8 shows how to make a transition
from horizontal to vertical. Finally, figure 9 shows how to
place the outdoor unit and line set.
Page 6
Refrigerant Line Sets
How To Install Vertical Runs
(new construction shown)
NOTE - Similar installation practices should be used if
line set is to be installed on exterior of outside wall.
Outside Wall
Wood Block
Between Studs
Liquid Line
Vapor Line
(wrapped with Armaflex)
Outside Wall
IMPORTANT - Refrigerant
lines must not contact wall.
Liquid LineVapor Line
Wire Tie
Inside Wall
Strap
Sleeve
Wire Tie
Wood Block
Wire Tie
Caulk
PVC Pipe
Fiberglass
Insulation
IMPORTANT - Refrigerant
lines must not contact
structure.
Strap
Sleeve
Figure 6
Page 7
Installing Horizontal Runs
To hang line set from joist or rafter,
use either metal strapping material
or anchored heavy nylon wire ties.
Floor Joist or
Roof Rafter
Refrigerant Line Sets:
Wire Tie
(around vapor line only)
8 feet
Tape or Wire Tie
8 feet
Strapping Material (around vapor line only)
Tape or Wire Tie
Metal Sleeve
Floor Joist or Roof Rafter
Strap the vapor line to the joist or rafter at 8 ft.
intervals then strap the liquid line to the vapor line.
Figure 7
Page 8
Refrigerant Line Sets:
Transition From Vertical To Horizontal
Anchored Heavy
Nylon Wire Tie
Wall
Stud
Metal
Sleeve
Vapor Line
Wrapped in
Armaflex
Strap Liquid Line
To Vapor Line
Liquid Line
Figure 8
Automotive
Muffler-Type
Hanger
Wall
Stud
Metal
Sleeve
Strap Liquid Line
To Vapor Line
Liquid Line
Vapor Line
Wrapped in
Armaflex
Outside Unit Placement and Installation
Install unit away from windows.
Two 90° elbows
installed in line set
will reduce line set
vibration.
Figure 9
Page 9
Brazing Connection Procedure
1 − Cut ends of the refrigerant lines square (free from nicks
or dents). Debur the ends. The pipe must remain
round, do not pinch end of the line.
2 − Before making line set connections, use dry nitrogen to
purge the refrigerant piping. This will help to prevent
oxidation and the introduction of moisture into the system.
3 − Use silver alloy brazing rods (5 or 6 percent minimum
silver alloy for copper−to−copper brazing or 45 percent
silver alloy for copper−to−brass or copper−to−steel brazing) which are rated for use with HCFC−22 refrigerant.
Wrap a wet cloth around the valve body and the copper
tube stub. Braze the line set to the service valve.
4 − Wrap a wet cloth around the valve body and copper
tube stub to protect it from heat damage during brazing. Wrap another wet cloth underneath the valve body
to protect the base paint.
NOTE − The tube end must stay bottomed in the fitting
during final assembly to ensure proper seating, sealing
and rigidity.
5 − Install a field−provided thermal expansion valve (ap-
proved for use with HCFC−22 refrigerant) in the liquid
line at the indoor coil.
Refrigerant Metering Device
H27 units are used in expansion valve systems only. See
the Lennox Engineering Handbook for approved TXV
match-ups and application information.
Expansion valves equipped with Chatleff fittings are available from Lennox. Refer to the Engineering Handbook for
applicable expansion valves for use with specific matchups.
If you install an expansion valve with an indoor coil that
includes a fixed orifice, remove the orifice before installing the expansion valve.
IMPORTANT
Failure to remove RFC orifice when installing an expansion valve on the indoor coil will result in improper operation and damage to the system.
See figure 10 for installation of the check expansion valve.
Metering Device Installation
distributor
o−ring
strainer
o−ring
expansion
valve
liquid line
stub
Figure 10
Manifold Gauge Set
When checking the unit charge, use a manifold gauge set
that is equipped with low loss" hoses. Do not use a manifold gauge set with anything other than a low loss" hose.
Service Valves
The liquid line and vapor line service valves (figures 11 and
12) and gauge ports are used for leak testing, evacuating,
charging and checking charge. See table 2 for torque requirements.
Each valve is equipped with a service port which has a factory−installed Schrader valve. A service port cap protects
the Schrader valve from contamination and serves as the
primary leak seal.
Table 2
Torque Requirements
Part Recommended Torque
Service valve cap 8 ft.− lb. 11 N M
Sheet metal screws 16 in.− lb. 2 NM
Machine screws #10 28 in.− lb. 3 NM
Compressor bolts 90 in.− lb. 10 NM
Gauge port seal cap 8 ft.− lb. 11 N M
To Access Schrader Port:
1 − Remove the service port cap with an adjustable wrench.
2 − Connect gauge to the service port.
3 − When testing is complete, replace the service port cap.
Tighten finger tight, then an additional 1/6 turn.
To Open Service Valve:
1 − Remove stem cap with an adjustable wrench.
2 − Use a service wrench with a hex−head extension to
back the stem out counterclockwise as far as it will go.
Page 10
NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.
3 − Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
To Close Service Valve:
1 − Remove stem cap with an adjustable wrench.
2 − Use a service wrench with a hex−head extension to turn
the stem clockwise to seat the valve. Tighten firmly.
NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.
3 − Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
Vapor Line (Ball Type) Service Valve
Vapor line service valves function the same way as the other valves, the difference is in the construction. These
valves are not rebuildable. If a valve has failed, you must
replace it. A ball valve is illustrated in figure 12.
The ball valve is equipped with a service port with a factory−
installed Schrader valve. A service port cap protects the
Schrader valve from contamination and assures a leak−
free seal.
Service Valve
(Valve Closed)
service
port
to outdoor coil
service
port cap
Schrader valve open
to line set when valve is
closed (front seated)
wrench here
(valve front seated)
stem cap
insert hex
to indoor coil
Vapor Line (Ball Type) Service Valve
(Valve Open)
To open: rotate stem counter-clockwise 90.
To close: use adjustable wrench and
rotate stem clockwise 90.
service port
Schrader
valve
service
port
field side
cap
ball
(shown open)
unit side
stem
stem cap
Figure 12
Leak Testing
After the line set has been connected to the indoor and
outdoor units, the line set connections and indoor unit
must be checked for leaks.
WARNING
Danger of fire. Bleeding the refrigerant
charge from only the high side may
result in the low side shell and suction tubing being pressurized. Appplication of a brazing torch while pressurized may result in ignition of the
refrigerant and oil mixture − check the
high and low pressures before unbrazing.
Service Valve
insert hex
wrench here
service
port
to outdoor coil
service port
cap
(Valve Open)
Schrader
valve
Figure 11
stem cap
to indoor coil
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in personal injury or death.
WARNING
Danger of explosion: Can cause
equipment damage, injury or death.
Never use oxygen to pressurize a refrigeration or air conditioning system.
Oxygen will explode on contact with
oil and could cause personal injury.
Page 11
WARNING
Danger of explosion: Can cause equipment damage,
injury or death. When using a high pressure gas
such as dry nitrogen to pressurize a refrigeration or
air conditioning system, use a regulator that can
control the pressure down to 1 or 2 psig (6.9 to 13.8
kPa).
Using an Electronic Leak Detector or Halide
1 − Connect a cylinder of HCFC-22 to the center port of the
manifold gauge set.
2 − With both manifold valves closed, open the valve on
the HCFC-22 cylinder (vapor only).
3 − Open the high pressure side of the manifold to allow
the HCFC-22 into the line set and indoor unit. Weigh in
a trace amount of HCFC-22. [A trace amount is a maxi-
mum of 2 ounces (57 g) or 3 pounds (31 kPa) pressure.] Close the valve on the HCFC-22 cylinder and the
valve on the high pressure side of the manifold gauge
set. Disconnect the HCFC-22 cylinder.
4 − Connect a cylinder of nitrogen with a pressure regulat-
ing valve to the center port of the manifold gauge set.
5 − Connect the manifold gauge set high pressure hose to
the vapor valve service port. (Normally, the high pres-
sure hose is connected to the liquid line port; however,
connecting it to the vapor port better protects the manifold gauge set from high pressure damage.)
6 − Adjust the nitrogen pressure to 150 psig (1034 kPa).
Open the valve on the high side of the manifold gauge
set which will pressurize line set and indoor unit.
7 − After a few minutes, open a refrigerant port to ensure
the refrigerant you added is adequate to be detected.
(Amounts of refrigerant will vary with line lengths.)
Check all joints for leaks. Purge nitrogen and HCFC-22
mixture. Correct any leaks and recheck.
2 − Connect micron gauge.
3 − Connect the vacuum pump (with vacuum gauge) to the
center port of the manifold gauge set.
4 − Open both manifold valves and start the vacuum
pump.
5 − Evacuate the line set and indoor unit to an absolute
pressure of 23,000 microns (29.01 inches of mercury). During the early stages of evacuation, it is desirable to close the manifold gauge valve at least once to
determine if there is a rapid rise in absolute pressure.
A rapid rise in pressure indicates a relatively large leak.
If this occurs, repeat the leak testing procedure.
NOTE − The term absolute pressure means the total
actual pressure within a given volume or system,
above the absolute zero of pressure. Absolute pressure in a vacuum is equal to atmospheric pressure minus vacuum pressure.
6 − When the absolute pressure reaches 23,000 microns
(29.01 inches of mercury), close the manifold gauge
valves, turn off the vacuum pump and disconnect the
manifold gauge center port hose from vacuum pump.
Attach the manifold center port hose to a nitrogen cylinder with pressure regulator set to 150 psig (1034 kPa)
and purge the hose. Open the manifold gauge valves
to break the vacuum in the line set and indoor unit.
Close the manifold gauge valves.
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.
Evacuation
Evacuating the system of noncondensables is critical for
proper operation of the unit. Noncondensables are defined
as any gas that will not condense under temperatures and
pressures present during operation of an air conditioning
system. Noncondensables and water vapor combine with
refrigerant to produce substances that corrode copper piping and compressor parts.
IMPORTANT
Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument
that reads from 50 microns to at least 10,000 microns.
1 − Connect manifold gauge set to the service valve ports
as follows:
low pressure gauge to vapor line service valve
high pressure gauge to liquid line service valve
7 − Shut off the nitrogen cylinder and remove the manifold
gauge hose from the cylinder. Open the manifold
gauge valves to release the nitrogen from the line set
and indoor unit.
8 − Reconnect the manifold gauge to the vacuum pump,
turn the pump on, and continue to evacuate the line set
and indoor unit until the absolute pressure does not
rise above 500 microns (29.9 inches of mercury) within
a 20−minute period after shutting off the vacuum pump
and closing the manifold gauge valves.
9 − When the absolute pressure requirement above has
been met, disconnect the manifold hose from the vacuum pump and connect it to an upright cylinder of
HCFC-22 refrigerant. Open the manifold gauge valves
to break the vacuum from 1 to 2 psig positive pressure in
the line set and indoor unit. Close manifold gauge
valves and shut off the HCFC-22 cylinder and remove
the manifold gauge set.
Page 12
Start−Up
1 − Rotate the fan to check for frozen bearings or binding.
2 − Inspect all factory− and field-installed wiring for loose
connections.
3 − After evacuation is complete, open the liquid line and
vapor line service valves to release the refrigerant
charge (contained in outdoor unit) into the system.
4 − Replace the stem caps and secure finger tight, then
tighten an additional one-sixth (1/6) of a turn.
5 − Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit’s
nameplate. If not, do not start the equipment until you
have consulted the power company and the voltage
condition has been corrected.
6 − Set the thermostat for a cooling demand. Turn on pow-
er to the indoor blower and close the outdoor unit disconnect switch to start the unit.
7 − Recheck voltage while the unit is running. Power must
be within range shown on the nameplate.
Charging
Units are factory charged with the amount of HCFC-22 refrigerant indicated on the unit nameplate. This charge is
based on a matching indoor coil and outdoor coil with a 15
ft. (4.6 m) line set. For varying lengths of line set, refer to
table 3 for refrigerant charge adjustment check.
Table 3
Liquid Line
Set Diameter
3/8 in. (9.5 mm) 3 ounces per 5 ft. (88.05 g per 1.5 m)
*If line length is greater than 15 ft. (4.6 m), add this amount. If line length
is less than 15 ft. (4.6 m), subtract this amount
The outdoor unit should be charged during warm weather.
However, applications arise in which charging must occur
in the colder months. The method of charging is deter-
mined by the unit’s refrigerant metering device and the
outdoor ambient temperature.
Oz. per 5 ft. (g per 1.5 m) adjust
from 15 ft. (4.6 m) line set*
Measure the liquid line temperature and the outdoor ambient temperature as outlined below. Close manifold gauge
set valves.
1 − Connect the manifold gauge set to the service valves:
low pressure gauge to vapor valve service port
high pressure gauge to liquid valve service port
Connect the center manifold hose to an upright cylinder of HCFC−22.
2 − Set the room thermostat to call for heat. This will create
the necessary load for properly charging the system in
the cooling cycle.
3 − Use a digital thermometer to record the outdoor ambi-
ent temperature.
4 − When the heating demand has been satisfied, switch
the thermostat to cooling mode with a set point of 68F
(20C). When pressures have stabilized, use a digital
thermometer to record the liquid line temperature.
5 − The outdoor temperature will determine which charg-
ing method to use. Proceed with the appropriate charging procedure.
Weighing in the Charge TXV Systems – Outdoor
Temp < 65F (18C)
If the system is void of refrigerant, or if the outdoor ambient
temperature is cool, the refrigerant charge should be
weighed into the unit. Do this after any leaks have been repaired.
1 − Recover the refrigerant from the unit.
2 − Conduct a leak check, then evacuate as previously
outlined.
3 − Weigh in the unit nameplate charge.
If weighing facilities are not available or if you are charging
the unit during warm weather, follow one of the other procedures outlined below.
Page 13
Charging Using Normal Operating Pressures
Outd
and the Approach Method
TXV Systems – Outdoor Temp. >
The following procedure is intended as a general guide and
is for use on expansion valve systems only. For best results,
indoor temperature should be 70°F (21°C) to 80°F (26°C).
Monitor system pressures while charging.
1 − Record outdoor ambient temperature using a digital
thermometer.
2 − Attach high pressure gauge set and operate unit for
several minutes to allow system pressures to stabilize.
3 − Compare stabilized pressures with those provided in
table 5, Normal Operating Pressures." Minor variations in these pressures may be expected due to differences in installations. Significant differences could
mean that the system is not properly charged or that a
problem exists with some component in the system.
Pressures higher than those listed indicate that the
system is overcharged. Pressures lower than those
listed indicate that the system is undercharged. Verify
adjusted charge using the approach method.
Approach Method
4 − Use the same digital thermometer you used to check
the outdoor ambient temperature to check the liquid
line temperature.
65F (18C)
5 − The difference between the ambient and liquid temper-
atures should match values given in table 4. If the values don’t agree with the those in table 4, add refrigerant to lower the approach temperature, or recover refrigerant from the system to increase the approach
temperature.
Table 4
Approach Values
Model Number
HS27−024 5 + 1 ( 3 + .5)
HS27−030 5 + 1 ( 3 + .5)
HS27−036 6 + 1 ( 3.3 + .5)
HS27−042 7 + 1 ( 3.9 + .5)
NOTE − For best results, the same digital thermometer should be
used to check both outdoor ambient and liquid temperatures.
Liquid Temp. Minus Ambient
Temp. °F (°C)
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 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.
See table 5.
Table 5
Normal Operating Pressure
oor
Temp. (F)
65 135 78 139 79 136 76 141 82
75 159 79 163 80 160 77 166 82
85 186 80 180 81 188 80 185 82
95 216 82 219 83 217 80 226 85
105 249 83 252 84 251 82 257 85
HS27−024 HS27−030 HS27−036 HS27−042
Liq. + 10
psig
Suct. + 5
psig
Liq. + 10
psig
Suct. + 5
psig
s
Liq. + 10
psig
Suct. + 5
psig
Liq. + 10
psig
Suct. + 5
psig
Page 14
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.
CAUTION
Danger of equipment damage. Do not bypass the discharge thermostat.
High Pressure Switch
HS27 units are equipped with a high pressure switch that is
located in the discharge line of the compressor. The switch
(SPST, manual reset, normally closed) removes power
from the compressor when discharge pressure rises above
factory setting at 410 + 10 psi.
Low Pressure Switch
HS27 units are also equipped with a low pressure switch
that is located in the vapor line of the compressor. The
switch (SPST, auto−reset, normally closed) removes power
from the compressor when vapor line pressure drops below factory setting at 25 + 5 psi.
Maintenance
WARNING
Electric shock hazard. Can cause injury or death. Before attempting to perform any service or maintenance, turn
the electrical power to unit OFF at disconnect switch(es). Unit may have
multiple power supplies.
Maintenance and service must be performed by a qualified
installer or service agency. At the beginning of each cooling
season, the system should be checked as follows:
1 − Clean and inspect the outdoor coil. The coil may be
flushed with a water hose. Ensure the power is turned
off before you clean the coil.
2 − The outdoor fan motor is prelubricated and sealed. No
further lubrication is needed.
3 − Visually inspect connecting lines and coils for evidence
of oil leaks.
4 − Check wiring for loose connections.
5 − Check for correct voltage at unit (unit operating).
6 − Check amp−draw outdoor fan motor.
Unit nameplate _________ Actual ____________ .
NOTE − If the owner complains of insufficient cooling,
the unit should be gauged and refrigerant charge
checked. Refer to section on refrigerant charging in
this instruction.
Indoor Coil
1 − Clean coil, if necessary.
2 − Check connecting lines and coils for evidence of oil leaks.
3 − Check the condensate line and clean it if necessary.
Indoor Unit
1 − Clean or change filters.
2 − Adjust blower speed for cooling. Measure the pressure
drop over the coil to determine the correct blower CFM.
Refer to the unit information service manual for pressure
drop tables and procedure.
3 − Belt Drive Blowers − Check belt for wear and proper
tension.
4 − Check all wiring for loose connections
5 − Check for correct voltage at unit (blower operating).
6 − Check amp−draw on blower motor
Unit nameplate_________ Actual ____________.
Optional Accessories
The following optional accessories are available for use
with outdoor units:
Loss of Charge Kit
High Pressure Switch Kit
Compressor Monitor
Compressor Crankcase Heater
Hail Guards
Mounting Bases
Timed Off Control
Stand−off Kit
Sound Cover
Low Ambient Kit
Page 15
Start−up & Performance Check List
Start−up and Performance Check List
Job Name
Job Location
Installer
Unit Model No.
Nameplate Voltage
Rated Load Ampacity
Maximum Fuse or Circuit Breaker
Electrical Connections Tight?
Indoor Blower RPM
Discharge Pressure
Refrigerant Lines:
Service Valves Fully Opened?
Voltage With Compressor Operating
Leak Checked?
S.P. Drop Over Indoor (Dry)
Vapor Pressure
Service Valve Caps Tight?
Job No.
City
City
Serial No.
Compressor
Indoor Filter Clean?
Properly Insulated?
Date
State
State
Service Technician
Outdoor Fan
Supply Voltage (Unit Off)
Outdoor Coil Entering Air Temp.
Refrigerant Charge Checked?
Outdoor Fan Checked?
Thermostat
Calibrated? Properly Set?
Level?
Page 16
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