Lennox EL15XP1 Series Installation and operation manual

Page 1
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 licensed professional HVAC installer or
equivalent, service agency, or the gas supplier.
IMPORTANT
The Clean Air Act of 1990 bans the intentional venting of
refrigerant (CFCs, HCFCs and HFCs) as of July 1, 1992.
Approved methods of recovery, recycling or reclaiming
must be followed. Fines and/or incarceration may be
levied for noncompliance.
IMPORTANT
This unit must be matched with an indoor coil as
specied in Lennox Product Specication bulletin. Coils
previously charged with HCFC-22 must be ushed.
CAUTION
As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment and wear gloves and
protective clothing.
WARNING
Electric Shock Hazard. Can cause injury or
death. Unit must be properly grounded in
accordance with national and local codes.
Line voltage is present at all components when
unit is not in operation on units with single-
pole contactors. Disconnect all remote electric
power supplies before opening access panel.
Unit may have multiple power supplies.
EL15XP1
Table of Contents
Installation Clearances ...................................................2
Model Number Identication...........................................2
Dimensions.....................................................................3
Specications .................................................................4
Typical Unit Parts Arrangement......................................6
Operating Gauge Set and Service Valves ......................6
Unit Placement ..............................................................8
New or Replacement Line Set........................................9
Brazing Connections ................................................... 11
Flushing Line Set and Indoor Coil ................................14
Installing Indoor Metering Device .................................15
Leak Test Line Set and Indoor Coil ..............................16
Evacuating Line Set and Indoor Coil ...........................17
Electrical.......................................................................18
System Operation .......................................................20
System Conguration ...................................................20
Defrost System ...........................................................23
Maintenance ...............................................................25
Wiring and Sequence of Operation ...........................27
Servicing Units Void of Charge ...................................29
Start-Up ......................................................................29
Service Literature
UNIT INFORMATION
Corp. 1704-L8
October 21, 2019
EL15XP1 (HFC-410A) SERIES OUTDOOR UNITS
General Information
These instructions are intended as a general guide and do
not supersede national or local codes in any way. Consult
authorities having jurisdiction before installation.
This EL15XP1 outdoor heat pump with all-aluminum coil
is designed for use with HFC-410A refrigerant only. This
unit must be installed with an approved indoor air handler
or coil. See the Lennox EL15XP1 Product Specications
bulletin (EHB) for approved indoor component match ups.
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
This outdoor unit is designed for use in systems that use
the following refrigerant metering device:
• Check thermal expansion valve (CTXV)
IMPORTANT: Special procedures are required for clean-
ing the all-aluminum coil in this unit. See page 25 in this
instruction for information.

Page 2
Installation Clearances
See
NOTES
See NOTES
See NOTES
See
NOTES
CONTROL
BOX
NOTES:
Service clearance of 30 in. (762 mm) must be maintained on
one of the sides adjacent to the control box.
Clearance to one of the other three sides must be
36 in. (914 mm)
Clearance to one of the remaining two sides may be
A clearance of 24 in. must be maintained between two units.
48 in. (1219 mm) clearance required on top of unit.
Model Number Identication
Nominal SEER
Unit Type
P = Heat Pump Outdoor Unit
Refrigerant Type
X = R-410A Nominal Cooling Capacity
018 = 1-1/2 tons
024 = 2 tons
030 = 2-1/2 tons
036 = 3 tons
042 = 3-1/2 tons
048 = 4 tons
060 = 5 tons
Revision Number
Voltage
230 = 208/230V-1ph-60hz
Product Tier
EL = Elite®Series
Cooling Stages
1 = Single Stage Compressor
EL 15 XP1- 036 - 230 A01
Ratings Revision Letter

Page 3
Dimensions
ELECTRICAL
INLETS
SIDE VIEW
DISCHARGE AIR
VAPOR LINE
CONNECTION
LIQUID LINE
CONNECTION
A
BC
4-1/4(108) 4-3/4
(121)
1 (25)
2 (51)
END VIEW
TOP VIEW
VAPOR LINE
CONNECTION
LIQUID LINE
CONNECTION
UNIT SUPPORT
FEET
16-7/8
(429)
26-7/8
(683)
30-3/4 (781)
3-1/8
(79)
8-3/4
(222) 3-3/4 (95)
4-5/8
(117)
UNIT SUPPORT
FEET
EL15XP1-018 TO -036 BASE SECTION
(Medium Base)
EL15XP1-042 TO -060 BASE SECTION
(Large Base)
13-7/8
(352)
3-5/8
(92)
20-5/8
(524)
7-3/4
(197)
27-1/8
(689)
4-1/2
(114)
3-1/4
(83)

Page 4
Specications
General
Data
Model No. EL15XP1-018EL15XP1-024EL15XP1-030EL15XP1-036
Nominal Tonnage 1.522.53
1 Sound Rating Number 71 71 71 72
Connections
(sweat)
Liquid line (o.d.) - in. 3/83/8 3/83/8
Suction line (o.d.) - in. 3/43/4 3/47/8
2 Refrigerant R-410A charge furnished 7 lbs. 0 oz.7lbs. 2 oz.7lbs 3 oz.8lbs. 10 oz.
Outdoor
Coil
Net face area - sq. ft. Outer coil 24.5 24.5 24.5 21.0
Inner coil - - --- --- -20.3
Tube diameter - in. 5/16 5/16 5/16 5/16
No. of rows 1112
Fins per inch 22 22 22 22
Outdoor
Fan
Diameter - in. 22 22 22 22
No. of blades 3333
Motor hp 1/61/6 1/61/6
Cfm 2670 2670 2890 2870
Rpm 867867 847839
Watts 160160 200205
Shipping Data - lbs. 1 pkg. 213213 213229
ELECTRICAL DATA
Line voltage data - 60hz 208/230V-1ph 208/230V-1ph 208/230V-1ph 208/230V-1ph
3Maximum overcurrent protection (amps) 20 20 25 30
4Minimum circuit ampacity 12.2 13.6 17.0 18.6
Compressor Rated load amps 9.010.112.814.1
Locked rotor amps 48 52 67.8 72.2
Power factor .98.98 .96.99
Outdoor Fan Motor Full load amps 1.01.0 1.01.0
Locked rotor amps 1.91.9 1.91.9
CONTROLS
iComfort®E30 Smart Wi-Fi Thermostat 15S63 ••••
Remote Outdoor Temperature Sensor X2658 ••••
OPTIONAL ACCESSORIES - ORDER SEPARATELY
Compressor Crankcase Heater 93M04 •••Factory
Compressor Hard
Start Kit
Copeland 10J42 •
LG 88M91 •••
45F08 ••••
Freezestat 3/8 in. tubing 93G35 ••••
5/8 in. tubing 50A93 ••••
58M81 ••••
5Low Ambient Kit 54M89 ••••
Mild Weather Kit 11B97 ••••
Monitor Kit - Service Light 76F53 ••••
Outdoor
Thermostat Kit
Thermostat 10Z23
••
Mounting Box 31461
••
Refrigerant
Line Sets
L15-41-20
L15-41-30
L15-41-40
L15-41-50 •••
L15-65-30 L15-65-40
L15-65-50 •
6 Snow Guard 35-1/2 x 31 in. (Canada Only)X8780 ••••
NOTE - Extremes of operating range are plus 10% and minus 5% of line voltage.
1Sound Rating Number rated in accordance with test conditions included in AHRI Standard 270.
2
additional refrigerant charge required.
3HACR type breaker or fuse.
4Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.
5Crankcase Heater and Freezestat are recommended with Low Ambient Kit.
6Adds 11-1/2 inches (292 mm) to unit height.

Page 5
SPECIFICATIONS
General
Data
Model No. EL15XP1-042EL15XP1-048EL15XP1-060
Nominal Tonnage 3.54 5
1 Sound Rating Number 72 73 73
Connections
(sweat)
Liquid line (o.d.) - in. 3/83/8 3/8
Suction line (o.d.) - in. 7/87/8 1-1/8
2 Refrigerant R-410A charge furnished 10 lbs. 11 oz. 10 lbs. 11 oz. 12 lbs. 5 oz.
Outdoor
Coil
Net face area - sq. ft. Outer coil 24.9 24.9 29.1
Inner coil 24.1 24.1 28.2
Tube diameter - in. 5/16 5/16 5/16
No. of rows 222
Fins per inch 22 22 22
Outdoor
Fan
Diameter - in. 22 22 22
No. of blades 444
Motor hp 1/41/4 1/4
Cfm 4347 4347 4550
Rpm 843843 830
Watts 299299 307
Shipping Data - lbs. 1 pkg. 285285 308
ELECTRICAL DATA
Line voltage data - 60hz 208/230V-1ph208/230V-1ph 208/230V-1ph
3Maximum overcurrent protection (amps) 45 45 50
4Minimum circuit ampacity 25.8 26.2 29.6
Compressor Rated load amps 19.2 19.6 22.2
Locked rotor amps 123.9130 127.9
Power factor .96.98 .99
Outdoor Fan Motor Full load amps 1.81.8 1.8
Locked rotor amps 3.23.2 3.2
CONTROLS
iComfort®E30 Smart Wi-Fi Thermostat 15S63 •••
Remote Outdoor Temperature Sensor X2658 •••
OPTIONAL ACCESSORIES - ORDER SEPARATELY
Compressor Hard Start
Kit
Copeland 10J42 ••
LG 88M91 •
45F08 •••
Freezestat 3/8 in. tubing 93G35 •••
5/8 in. tubing 50A93 •••
58M81 •••
5Low Ambient Kit 54M89 •••
Mild Weather Kit 11B97 •••
Monitor Kit - Service Light 76F53 •••
Outdoor
Thermostat Kit
Thermostat 10Z23 •••
Mounting Box 31461 •••
Refrigerant Line Sets L15-65-30 L15-65-40
L15-65-50
•••
6Snow Guard 39-1/2 X 35-5/8 in. Y1033 •••
NOTE - Extremes of operating range are plus 10% and minus 5% of line voltage.
1Sound Rating Number rated in accordance with test conditions included in AHRI Standard 270.
2
additional refrigerant charge required.
3HACR type breaker or fuse.
4Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.
5Crankcase Heater and Freezestat are recommended with Low Ambient Kit.
6Adds 11-1/2 inches (292 mm) to unit height.

Page 6
Typical Unit Parts Arrangement
BI-FLOW FILTER DRIER
CHECK / EXPANSION VALVE
VAPOR LINE SERVICE VALVE
HIGH PRESSURE SWITCH
REVERSING VALVE
LOW PRESSURE SWITCH
LIQUID LINE SERVICE VALVE
FIGURE 1. Typical Plumbing Arrangement
Operating Gauge Set and Service Valves
TORQUE REQUIREMENTS
When servicing or repairing heating, ventilating, and air
conditioning components, ensure the fasteners are appro-
priately tightened. Table 1 lists torque values for fasteners.
IMPORTANT
Only use Allen wrenches of su󰀩cient hardness (50Rc
- Rockwell Harness Scale minimum). Fully insert the
wrench into the valve stem recess.
Service valve stems are factory-torqued (from 9 ft-lbs
for small valves, to 25 ft-lbs for large valves) to prevent
refrigerant loss during shipping and handling. Using an
Allen wrench rated at less than 50Rc risks rounding
or breaking o󰀨 the wrench, or stripping the valve stem
recess.
See the Lennox Service and Application Notes #C-08-1
for further details and information.
IMPORTANT
To prevent stripping of the various caps used, the
appropriately sized wrench should be used and tted
snugly over the cap before tightening.
TABLE 1. Torque Requirements
Parts Recommended Torque
Service valve cap 8 ft.- lb. 11 NM
Sheet metal screws 16 ft.- lb. 2 NM
Machine screws #10 28 ft.- lb. 3 NM
Compressor bolts 90 in.- lb. 10 NM
Gauge port seal cap 8 ft.- lb. 11 NM
USING MANIFOLD GAUGE SET
When checking the system charge, only use a manifold
gauge set that features low loss anti-blow back ttings.
Manifold gauge set used with HFC-410A refrigerant sys-
tems must be capable of handling the higher system oper-
ating pressures. The gauges should be rated for use with
pressures of 0 - 800 psig on the high side and a low side
of 30” vacuum to 250 psig with dampened speed to 500
psi. Gauge hoses must be rated for use at up to 800 psig
of pressure with a 4000 psig burst rating.
OPERATING SERVICE VALVES
The liquid and vapor line service valves are used for re-
moving refrigerant, ushing, leak testing, evacuating,
checking charge and charging. Each valve is equipped
with a service port which has a factory-installed valve
stem. Figure 2 provides information on access and opera-
tion of both angle and ball service valves

Page 7
(VALVE STEM SHOWN
CLOSED) INSERT HEX
WRENCH HERE
SERVICE PORT CORE
SERVICE PORT CAP
ANGLE-TYPE SERVICE VALVE
(FRONT-SEATED CLOSED)
SERVICE PORT
CORE
TO OUTDOOR UNIT
STEM CAP
(VALVE STEM SHOWN OPEN)
INSERT HEX WRENCH HERE
TO INDOOR
UNIT
ANGLE-TYPE SERVICE VALVE
(BACK-SEATED OPENED)
BALL (SHOWN
CLOSED)
SERVICE PORT
CORE
TO INDOOR UNIT
TO OUTDOOR
UNIT
TO OPEN ROTATE STEM
COUNTERCLOCKWISE 90°.
TO CLOSE ROTATE STEM
CLOCKWISE 90°.
SERVICE PORT
SERVICE PORT
CAP
STEM CAP
VALVE
STEM
SERVICE VALVES
ANGLE AND BALL
Operating Angle Type Service Valve:
1. Remove stem cap with an appropriately sized wrench.
2. Use a service wrench with a hex-head extension (3/16” for liquid line valve sizes and 5/16” for vapor line valve sizes) to back
the stem out counterclockwise as far as it will go.
Operating Ball Type Service Valve:
1. Remove stem cap with an appropriately sized wrench.
2. Use an appropriately sized wrenched to open. To open valve,
roate stem counterclockwise 90°. To close rotate stem clockwise
90°.
12
3
4
5
6
7
8
9
10
11 12
1/12 TURN
To Access Service Port:
A service port cap protects the service port core from contamination and
serves as the primary leak seal.
1. Remove service port cap with an appropriately sized wrench.
2. Connect gauge set to service port.
3. When testing is completed, replace service port cap and tighten as
follows:
With torque wrench: Finger tighten and
torque cap per table 3.
Without torque wrench: Finger tighten and
use an appropriately sized wrench to turn
an additional 1/6 turn clockwise.
12
3
4
5
6
7
8
9
10
11 12
1/6 TURN
WHEN SERVICEVALVEIS CLOSED,THESERVICEPORT IS OPEN
TO THELINE SETANDINDOOR UNIT.
When service valve is OPEN, the service port is
open to linE set, indoor and outdoor unit.
Reinstall Stem Cap:
Stem cap protects the valve stem from damage and serves as the
primary seal. Replace the stem cap and tighten as follows:
With Torque Wrench: Finger tighten and
then torque cap per table 3.
Without Torque Wrench: Fi
en and use an appropriately sized
wrench to turn an additional 1/12 turn
clockwise.
NOTE — A label with specific torque requirements may be affixed to the stem cap. If the label is present, use the specified torque.
FIGURE 2. Angle and Ball Service Valves

Page 8
INSTALL UNIT LEVEL OR, IF ON A SLOPE, MAINTAIN SLOPE TOLERANCE
OF 2 DEGREES (OR 2 INCHES PER 5 FEET [50 MM PER 1.5 M]) AWAY
FROM BUILDING STRUCTURE.
DETAIL A DETAIL B
INSTALL UNIT AWAY
FROM WINDOWS
TWO 90 ELBOWS INSTALLED IN LINE SET
WILL REDUCE LINE SET VIBRATION GROUND LEVEL
MOUNTING
SLAB
BUILDING
STRUCTURE
DISCHARGE AIR
FIGURE 3. Placement and Slab Mounting
Unit Placement
See Unit Dimensions on page 3 for sizing mounting slab,
platforms or supports. Refer to page 2 for mandatory in-
stallation clearance requirements.
CAUTION
In order to avoid injury, take proper precaution when
lifting heavy objects..
POSITIONING CONSIDERATIONS
Consider the following when positioning the unit:
• Some localities are adopting sound ordinances based
on the unit's sound level registered from the adjacent
property, not from the installation property. 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 trans-
mission. For proper placement of unit in relation to a
window see the provided illustration in gure 3, detail A.
PLACING UNIT ON SLAB
When installing unit at grade level, the top of the slab
should be high enough above grade so that water from
higher ground will not collect around the unit. The slab
should have a slope tolerance as described in gure 3,
detail B.
ROOF MOUNTING
Install the unit a minimum of 6 inches (152 mm) above the
roof surface to avoid ice build-up around the unit. Locate
the unit above a load bearing wall or area of the roof that
can adequately support the unit. Consult local codes for
rooftop applications.
If unit coil cannot be mounted away from prevailing winter
winds, a wind barrier should be constructed. Size barrier
at least the same height and width as outdoor unit. Mount
barrier 24 inches (610 mm) from the sides of the unit in the
direction of prevailing winds.
NOTICE
Roof Damage!
This system contains both refrigerant and oil. Some
rubber roong material may absorb oil, causing the
rubber to swell. Bubbles in the rubber roong material
can cause leaks. Protect the roof surface to avoid
exposure to refrigerant and oil during service and
installation. Failure to follow this notice could result in
damage to roof surface.

Page 9
New or Replacement Line Set
This section provides information on new installation or re-
placement of existing line set. If a new or replacement line
set is not required, then proceed to Brazing Connections
on page 11.
If refrigerant lines are routed through a wall, seal and
isolate the opening so vibration is not transmitted to the
building. Pay close attention to line set isolation during
installation of any HVAC system. When properly isolated
from building structures (walls, ceilings. oors), the refrig-
erant lines will not create unnecessary vibration and sub-
sequent sounds.
REFRIGERANT LINE SET
Field refrigerant piping consists of liquid and suction lines
from the outdoor unit (braze connections) to the indoor
unit coil (are or braze connections). Use Lennox L15
(braze, non-are) series line set, or use eld-fabricated
refrigerant lines as listed in table 2.
TABLE 2. Refrigerant Line Set – in. (mm)
Model
Valve Field
Connections Recommended Line Set
Liquid
Line
Vapor
Line
Liquid
Line
Vapor
Line L15 Line Sets
-018
3/8 in.
(10 mm)
3/4 in.
(19 mm)
3/8 in.
(10 mm)
3/4 in.
(19 mm)
L15-41
15 ft. - 50 ft.
(4.6 m - 15 m)
-024
-030
-036
3/8 in.
(10 mm)
7/8 in.
(22 mm)
3/8 in.
(10 mm)
7/8 in.
(22 mm)
L15-65
15 ft. - 50 ft.
(4.6 m - 15 m)
-042
-048
-060 3/8 in.
(10 mm)
1-1/8 in.
(28 mm)
3/8 in.
(10 mm)
1-1/8 in.
(28 mm) Field Fabricated
NOTE - Some applications may require a eld-provided 7/8" to
1-1/8"adapter.
NOTE – When installing refrigerant lines longer than 50
feet, contact Lennox Technical Support Product Applica-
tions for assistance or Lennox piping manual. To obtain
the correct information from Lennox, be sure to communi-
cate the following points:
• Model (EL15XP1) and size of unit (e.g. -060).
• Line set diameters for the unit being installed as listed in
table 4 and total length of installation.
• Number of elbows and if there is a rise or drop of the piping.
IMPORTANT
Mineral oils are not compatible with HFC-410A. If oil
must be added, it must be a Polyol ester oil.
The compressor is charged with su󰀩cient Polyol ester oil
for line set lengths up to 50 feet. Recommend adding oil to
system based on the amount of refrigerant charge in the
system. No need to add oil in system with 20 pounds of
refrigerant or less. For systems over 20 pounds - add one
ounce for every ve pounds of refrigerant.
Recommended topping-o󰀨 POE oils are Mobil EAL ARC-
TIC 22 CC or ICI EMKARATE RL32CF.
MATCHING WITH NEW OR EXISTING INDOOR COIL
AND LINE SET
The RFC1-metering line consisted of a small bore copper
line that ran from condenser to evaporator coil. Refrig-
erant was metered into the evaporator by utilizing tem-
perature/pressure evaporation e󰀨ects on refrigerant in the
small RFC line. The length and bore of the RFC line cor-
responded to the size of cooling unit. If the EL15XP1 is
being used with either a new or existing indoor coil which
is equipped with a liquid line which served as a meter-
ing device (RFCI), the liquid line must be replaced prior to
the installation of the EL15XP1 unit. Typically a liquid line
used to meter ow is 1/4” in diameter and copper.
LINE SET INSTALLATION AND ISOLATION
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 non-compliance.
IMPORTANT
If this unit is being matched with an approved line set
or indoor unit coil that was previously charged with
mineral oil, or if it is being matched with a coil which
was manufactured before January of 1999, the coil and
line set must be ushed prior to installation. Take care to
empty all existing traps. Polyol ester (POE) oils are used
in Lennox units charged with HFC-410A refrigerant.
Residual mineral oil can act as an insulator, preventing
proper heat transfer. It can also clog the expansion
device and reduce system performance and capacity.
Failure to properly ush the system, per this instruction
and the detailed Installation and Service Procedures
manual will void the warranty.

Page 10
ANCHORED HEAVY NYLON
WIRE TIE OR AUTOMOTIVE
MUFFLER‐TYPE HANGER
STRAP LIQUID LINE TO
VAPOR LINE
WALL
STUD
LIQUID LINE
NON-CORROSIVE
METAL SLEEVE
VAPOR LINE - WRAPPED
IN ARMAFLEX
AUTOMOTIVE
MUFFLER‐TYPE HANGER
REFRIGERANT LINE SET — TRANSITION
FROM VERTICAL TO HORIZONTAL
Line Set Isolation — The following illustrations are
examples of proper refrigerant line set isolation:
STRAPPING
MATERIAL (AROUND
VAPOR LINE ONLY)
TAPE OR
WIRE TIE
WIRE TIE (AROUND
VAPOR LINE ONLY)
FLOOR JOIST OR
ROOF RAFTER
TAPE OR
WIRE TIE
To hang line set from joist or rafter, use either metal strapping material
or anchored heavy nylon wire ties.
8 FEET (2.43 METERS)
STRAP THE VAPOR LINE TO THE JOIST
OR RAFTER AT 8 FEET (2.43 METERS)
INTERVALS THEN STRAP THE LIQUID
LINE TO THE VAPOR LINE.
FLOOR JOIST OR
ROOF RAFTER
REFRIGERANT LINE SET — INSTALLING
HORIZONTAL RUNS
NOTE — Similar installation practices should be used if line set is
to be installed on exterior of outside wall.
PVC
PIPE
FIBERGLASS
INSULATION
CAULK
OUTSIDE
WALL
VAPOR LINE WRAPPED
WITH ARMAFLEX
LIQUID
LINE
OUTSIDE WALL LIQUID LINE
VAPOR LINE
WOOD BLOCK
BETWEEN STUDS
STRAP
WOOD BLOCK
STRAP
SLEEVE
WIRE TIE
WIRE TIE
WIRE TIE
INSIDE WALL
REFRIGERANT LINE SET — INSTALLING
VERTICAL RUNS (NEW CONSTRUCTION SHOWN)
INSTALLATION
LINE SET
NOTE — Insulate liquid line when it is routed through areas where the
surrounding ambient temperature could become higher than the
temperature of the liquid line or when pressure drop is equal to or greater
than 20 psig.
NON-CORROSIVE
METAL SLEEVE
IMPORTANT —Refrigerant lines must not contact structure.
NON-CORROSIVE
METAL SLEEVE
8 FEET (2.43 METERS)
IMPORTANT —Refrigerant lines must not contact wall
WARNING — Polyol ester (POE) oils used with HFC-410A
refrigerant absorb moisture very quickly. It is very important that the
refrigerant system be kept closed as much as possible. DO NOT
remove line set caps or service valve stub caps until you are ready
to make connections.
FIGURE 4. Line Set Installation

Page 11
Brazing Connections
Use the procedures outlined in gures 5 and 6 for brazing
line set connections to service valves.
WARNING
Danger of re. Bleeding the refrigerant
charge from only the high side may result
in pressurization of the low side shell and
suction tubing. Application of a brazing torch
to a pressurized system may result in ignition
of the refrigerant and oil mixture. Check the
high and low pressures before applying heat.
WARNING
When using a high pressure gas such as
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).
CAUTION
Brazing alloys and ux contain materials which are
hazardous to your health.
Avoid breathing vapors or fumes from brazing operations.
Perform operations only in well-ventilated areas.
Wear gloves and protective goggles or face shield to
protect against burns.
Wash hands with soap and water after handling brazing
alloys and ux.
IMPORTANT
Allow braze joint to cool before removing the wet rag
from the service valve. Temperatures above 250ºF can
damage valve seals.
IMPORTANT
Use silver alloy brazing rods with 5% minimum silver
alloy for copper-to-copper brazing. Use 45% minimum
alloy for copper-to-brass and copper-to-steel brazing.
WARNING
Fire, Explosion and Personal Safety hazard.
Failure to follow this warning could result in
damage, personal injury or death.
Never use oxygen to pressurize or purge
refrigeration lines. Oxygen, when exposed
to a spark or open ame, can cause re and/
or an explosion, that could result in property
damage, personal injury or death.

Page 12
ATTACH THE MANIFOLD GAUGE SET FOR BRAZING LIQUID AND SUCTION / VAPOR LINE SERVICE
VALVES
OUTDOOR
UNIT
LIQUID LINE
VAPOR LINE
LIQUID LINE SERVICE
VALVE
SUCTION /
VAPOR LINE
SERVICE
VALVE
ATTACH
GAUGES
INDOOR
UNIT
SUCTION / VAPOR SERVICE PORT MUST BE
OPEN TO ALLOW EXIT POINT FOR NITROGEN
AConnect gauge set low pressure side to
liquid line service valve (service port).
BConnect gauge set center port to bottle of
nitrogen with regulator.
CRemove core from valve in suction / vapor
line service port to allow nitrogen to escape.
NITROGEN
HIGHLOW
USE REGULATOR TO FLOW
NITROGEN AT 1 TO 2 PSIG.
B
A
C
WHEN BRAZING LINE SET TO
SERVICE VALVES, POINT FLAME
AWAY FROM SERVICE VALVE.
Flow regulated nitrogen (at 1 to 2 psig) through the low-side refrigeration gauge set into the liquid line service port valve, and out of the suction /
vapor line service port valve.
CUT AND DEBUR CAP AND CORE REMOVAL
Cut ends of the refrigerant lines square (free from nicks or dents)
and debur the ends. The pipe must remain round. Do not crimp end
of the line.
Remove service cap and core from
both the suction / vapor and liquid line
service ports.
1
2
LIQUID LINE SERVICE
VALVE
SERVICE
PORT
CORE
SERVICE PORT
CAP
SERVICE
PORT
CORE
SERVICE
PORT CAP
CUT AND DEBUR
LINE SET SIZE MATCHES
SERVICE VALVE CONNECTION
COPPER TUBE
STUB
SERVICE VALVE
CONNECTION
REFRIGERANT LINE
DO NOT CRIMP SERVICE VALVE
CONNECTOR WHEN PIPE IS
SMALLER THAN CONNECTION
REDUCER
3
SUCTION / VAPOR LINE
SERVICE VALVE
LINE SET SIZE IS SMALLER
THAN CONNECTION
FIGURE 5. Brazing Procedures

Page 13
WHEN BRAZING LINE SET TO
SERVICE VALVES, POINT FLAME
AWAY FROM SERVICE VALVE.
LIQUID LINE SERVICE VALVE
LIQUID LINE
BRAZE LINE SET
Wrap both service valves with water saturated cloths as illustrated here and as mentioned in step 4, before brazing to line set. Water
saturated cloths must remain water saturated throughout the brazing and cool-down process.
WATER SATURATED
CLOTH
IMPORTANT — Allow braze joint to cool. Apply
additional water saturated cloths to help cool brazed
joint. Do not remove water saturated cloths until piping
has cooled. Temperatures above 250ºF will damage
valve seals.
6
SUCTION / VAPOR LINE
WATER SATURATED
CLOTH
SUCTION / VAPOR LINE
SERVICE VALVE
After all connections have been brazed, disconnect manifold gauge set from service ports. Apply additional water saturated cloths to both
services valves to cool piping. Once piping is cool, remove all water saturated cloths. Refer to the unit installation instructions for the next step
in preparing the unit.
WHEN BRAZING LINE SET TO
SERVICE VALVES, POINT FLAME
AWAY FROM SERVICE VALVE.
PREPARATION FOR NEXT STEP
7
WARNING
1. FIRE, PERSONAL INJURY, OR PROPERTY
DAMAGE may result if you do not wrap a water
saturated cloth around both liquid and suction line
service valve bodies and copper tube stub while
brazing in the line set! The braze, when complete,
must be quenched with water to absorb any residual
heat.
2. Do not open service valves until refrigerant lines and
indoor coil have been leak-tested and evacuated.
Refer to procedures provided in this supplement.
WRAP SERVICE VALVES
To help protect service valve seals during brazing, wrap water saturated cloths around service valve bodies and copper tube stubs. Use
additional water saturated cloths underneath the valve body to protect the base paint.
4
FLOW NITROGEN
Flow regulated nitrogen (at 1 to 2 psig) through the refrigeration gauge set into the valve stem port connection on the liquid service valve and
out of the suction / vapor valve stem port. See steps 3A, 3B and 3C on manifold gauge set connections
5
FIGURE 6. Brazing Procedures (continued)

Page 14
Flushing Line Set and Indoor Coil
SENSING
LINE
TEFLON®RING
FIXED ORIFICE
BRASS NUT
LIQUID LINE ASSEMBLY
(INCLUDES STRAINER)
LIQUID LINE ORIFICE HOUSING
DISTRIBUTOR TUBES
DISTRIBUTOR
ASSEMBLY
REMOVE AND DISCARD
WHITE TEFLON®SEAL
(IF PRESENT)
AOn fully cased coils, remove the coil access and plumbing panels.
BRemove
sembly.
CUsing two wrenches, disconnect liquid line from liquid
ing. T
cess.
DRemove and discard fixed orifice, valve stem assembly if present and
Teflon®washer as illustrated above.
EUse a field-provided fitting to temporarily reconnect the liquid line to the
indoor unit's liquid line orifice housing.
TYPICAL EXISTING FIXED ORIFICE
REMOVAL PROCEDURE (UNCASED
COIL SHOWN)
TYPICAL EXISTING EXPANSION VALVE REMOVAL
PROCEDURE (UNCASED COIL SHOWN)
TWO PIECE PATCH PLATE
(UNCASED COIL ONLY)
VAPOR
LINE
DISTRIBUTOR
ASSEMBLY
DISTRIBUTOR
TUBES
LIQUID
LINE
MALE EQUALIZER
LINE FITTING
EQUALIZER
LINE
CHECK
EXPANSION
VALVE
TEFLON®
RING
STUB END
TEFLON®
RING
SENSING BULB
LIQUID LINE
ORIFICE
HOUSING
LIQUID LINE
ASSEMBLY WITH
BRASS NUT
AOn fully cased coils, remove the coil access and plumbing panels.
BRemove any shipping clamps holding the liquid line and distributor
assembly.
CDisconnect the equalizer line from the check expansion valve
equalizer line fitting on the vapor line.
DRemove the vapor line sensing bulb.
EDisconnect the liquid line from the check expansion valve at the liquid
line assembly.
FDisconnect the check expansion valve from the liquid line orifice
housing. Ta ke care not to twist or damage distributor tubes during this
process.
GRemove and discard check expansion valve and the two Teflon®rings.
HUse a field-provided fitting to temporary reconnect the liquid line to the
indoor unit's liquid line orifice housing.
LOW HIGH
EXISTING
INDOOR
UNIT
GAUGE
MANIFOLD
INVERTED CYLINDER
CONTAINS CLEAN
HCFC22* TO BE USED
FOR FLUSHING.
LIQUID LINE SERVICE
VALVE
INLET
DISCHARGE
TANK
RETURN
CLOSED
OPENED
RECOVERY CYLINDERRECOVERY MACHINE
NEW
OUTDOOR
UNIT
VAPOR LINE
SERVICE VALVE
VAPOR
LIQUID
1
AInverted HCFC-22 cylinder with clean refrigerant* to the vapor service
valve.
BHCFC-22 gauge set (low side) to the liquid line valve.
CHCFC-22 gauge set center port to inlet on the recovery machine with an
empty recovery tank to the gauge set.
DConnect recovery tank to recovery machines per machine instructions.
CONNECT GAUGES AND EQUIPMENT FOR
FLUSHING PROCEDURE
A
B
C
D
B
OR
FLUSHING LINE SET
ASet the recovery machine for liquid recovery and start the
recovery machine. Open the gauge set valves to allow the
recovery machine to pull a vacuum on the existing system line
set and indoor unit coil.
BInvert the cylinder of clean HCFC-22* and open its valve to allow
liquid refrigerant to flow into the system through the vapor line
valve. Allow the refrigerant to pass from the cylinder and through
the line set and the indoor unit coil before it enters the recovery
machine.
CAfter all of the liquid refrigerant has been recovered, switch the
recovery machine to vapor recovery so that all of the HCFC-22
vapor is recovered. Allow the recovery machine to pull the
system down to 0.
DClose the valve on the inverted HCFC-22 drum and the gauge
set valves. Pump the remaining refrigerant out of the recovery
machine and turn the machine off.
The line set and indoor unit coil must be flushed with at least the
same amount of clean refrigerant* that previously charged the
system. Check the charge in the flushing cylinder before
proceeding.
1A
2
3
1B
*IMPORTANT - Clean refrigerant is any refrigerant in a system that has not had compressor burn out. If the system
has experienced burn out, it is recommended that the existing line set and indoor coil be replaced.
FIGURE 7. Removing Metering Device and Flushing

Page 15
Installing Indoor Metering Device
AAttach the vapor line sensing bulb in the proper
orientation as illustrated to the right using the clamp and
screws provided.
NOTE — Confirm proper thermal contact between vapor line
and expansion bulb before insulating the sensing bulb once
installed.
BConnect the equalizer line from the expansion valve to
the equalizer vapor port on the vapor line. Finger tighten
the flare nut plus 1/8 turn (7 ft-lbs) as illustrated below.
TWO PIECE
PATCH PLATE
(UNCASED
COIL ONLY)
VAPOR
LINE
LIQUID LINE
ORIFICE
HOUSING
DISTRIBUTOR
TUBES
LIQUID LINE
MALE EQUALIZER LINE
FITTING (SEE
EQUALIZER LINE
INSTALLATION FOR
FURTHER DETAILS)
SENSING
LINE
EQUALIZER
LINE
EXPANSION
VALVE
TEFLON®
RING
(Uncased Coil Shown)
Sensing bulb insulation is required if
mounted external to the coil casing. sensing
bulb installation for bulb positioning.
STUB
END
TEFLON®
RING
LIQUID LINE
ASSEMBLY WITH
BRASS NUT
DISTRIBUTOR
ASSEMBLY
ARemove the field-provided fitting that temporary
reconnected the liquid line to the indoor unit's distributor
assembly.
BInstall one of the provided Teflon®rings around the
stubbed end of the expansion valve and lightly lubricate
the connector threads and expose surface of the Teflon®
ring with refrigerant oil.
CAttach the stubbed end of the expansion valve to the
liquid line orifice housing. Finger tighten and use an
appropriately sized wrench to turn an additional 1/2 turn
clockwise as illustrated in the figure above, or 20 ft-lb.
DPlace the remaining Teflon®washer around the other
end of the expansion valve. Lightly lubricate connector
threads and expose surface of the Teflon®ring with
refrigerant oil.
EAttach the liquid line assembly to the expansion valve.
Finger tighten and use an appropriately sized wrench to
turn an additional 1/2 turn clockwise as illustrated in the
figure above or 20 ft-lb.
ON 7/8” AND LARGER LINES,
MOUNT SENSING BULB AT
EITHER THE 4 OR 8 O'CLOCK
POSITION. NEVER MOUNT ON
BOTTOM OF LINE.
12
ON LINES SMALLER THAN
7/8”, MOUNT SENSING
BULB AT EITHER THE 3 OR
9 O'CLOCK POSITION.
12
BULB
VAPOR LINE
VAPOR LINE
NOTE — NEVER MOUNT ON BOTTOM OF LINE.
BULB
BULB
BULB
VAPOR LINE
FLARE NUT
COPPER FLARE
SEAL BONNET
MALE BRASS EQUALIZER
LINE FITTING
FLARE SEAL CAP
OR
12
3
4
5
6
7
8
9
10
11 12
1/2 Turn
SENSING BULB INSTALLATION
EQUALIZER LINE INSTALLATION
12
3
4
5
6
7
8
9
10
11 12
1/8 Turn
ARemove and discard either the flare seal cap or flare nut
with copper flare seal bonnet from the equalizer line port
on the vapor line as illustrated in the figure to the right.
BRemove and discard either the flare seal cap or flare nut
with copper flare seal bonnet from the equalizer line port on
the vapor line as illustrated in the figure to the right.
INDOOR EXPANSION VALVE INSTALLATION
FIGURE 8. Installing Indoor Expansion Valve
This outdoor unit is designed for use in systems that use a
check expansion valve metering device at the indoor coil.
See the Lennox EL15XP1 Product Specication bulletin
for approved expansion valve kit match-ups. The expan-
sion valve unit can be installed internal or external to the
indoor coil.
In applications where an uncased coil is being installed in
a eld-provided plenum, install the expansion valve in a
manner that will provide access for eld servicing of the
expansion valve. Refer to below illustration for reference
during installation of expansion valve unit.

Page 16
Leak Test Line Set and Indoor Coil
WARNING
When using a high pressure gas such as
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).
IMPORTANT
Leak detector must be capable of sensing HFC
refrigerant.
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.
TO VAPOR
SERVICE VALVE
HFC-410A
MANIFOLD GAUGE SET
OUTDOOR UNIT
HIGHLOW
NITROGEN
AWith both manifold valves closed, connect the cylinder of HFC-410A refrigerant to the center port of the manifold gauge set. Open the valve
on the HFC-410A cylinder (vapor only).
BOpen the high pressure side of the manifold to allow HFC-410A into the line set and indoor unit. Weigh in a trace amount of HFC-410A. [A
trace amount is a maximum of two ounces (57 g) refrigerant or three pounds (31 kPa) pressure]. Close the valve on the HFC-410A cylinder
and the valve on the high pressure side of the manifold gauge set. Disconnect the HFC-410A cylinder.
CConnect a cylinder of dry nitrogen with a pressure regulating valve to the center port of the manifold gauge set.
DAdjust dry nitrogen pressure to 150 psig (1034 kPa). Open the valve on the high side of the manifold gauge set in order to pressurize the line set
and the indoor unit.
EAfter a few minutes, open one of the service valve ports and verify that the refrigerant added to the system earlier is measurable with a leak
detector.
FAfter leak testing disconnect gauges from service ports.
After the line set has been connected to the indoor and outdoor units, check the line set connections and indoor unit for leaks. Use the
following procedure to test for leaks:
AConnect an HFC-410A manifold gauge set high pressure
hose to the vapor valve service port.
NOTE — Normally, the high pressure 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.
BWith both manifold valves closed, connect the cylinder of
HFC-410A refrigerant to the center port of the manifold gauge
set.
NOTE — Later in the procedure,
the HFC-410A container will be
replaced by the nitrogen
container.
1
CONNECT GAUGE SET
2TEST FOR LEAKS
A
B
FIGURE 9. Leak Test

Page 17
Evacuating Line Set and Indoor Coil
AOpen both manifold valves and start the vacuum pump.
BEvacuate the line set and indoor unit to an absolute pressure of 23,000 microns (29.01 inches of mercury).
NOTE — During the early stages of evacuation, it is desirable to close the manifold gauge valve at least once. 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.
CWhen the absolute pressure reaches 23,000 microns (29.01 inches of mercury), perform the following:
Close manifold gauge valves
Close valve on vacuum pump
Turn off vacuum pump
Disconnect manifold gauge center port hose from vacuum pump
Attach manifold center port hose to a dry nitrogen cylinder with pressure regulator set to 150 psig (1034 kPa) and purge the hose.
Open manifold gauge valves to break the vacuum in the line set and indoor unit.
Close manifold gauge valves.
DShut off the dry nitrogen cylinder and remove the manifold gauge hose from the cylinder. Open the manifold gauge valves to release the
dry nitrogen from the line set and indoor unit.
EReconnect 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.
FWhen the absolute pressure requirement above has been met, disconnect the manifold hose from the vacuum pump and connect it to an
upright cylinder of HFC-410A refrigerant. Open the manifold gauge valve 1 to 2 psig in order to release the vacuum in the line set and
indoor unit.
GPerform the following:
OUTDOOR
UNIT
TO VAPOR
SERVICE VALVE
TO LIQUID LINE
SERVICE VALVE
MICRON
GAUGE
VACUUM PUMP
A34000 1/4 SAE TEE WITH
SWIVEL COUPLER
500
MANIFOLD
GAUGE SET
HFC-410A
RECOMMEND
MINIMUM 3/8” HOSE
AConnect low side of manifold gauge set
with 1/4 SAE in-line tee to vapor line
service valve
BConnect high side of manifold gauge
set to liquid line service valve
CConnect micron gauge available
connector on the 1/4 SAE in-line tee.
DConnect the vacuum pump (with
vacuum gauge) to the center port of the
manifold gauge set. The center port
line will be used later for both the
HFC-410A and nitrogen containers.
HIGH
LOW
1
2
3
4
5
6
7
8
9
10
11 12
1/6 TURN
NITROGEN
1
CONNECT GAUGE SET
A
B
C
D
2EVACUATE THE SYSTEM
NOTE — Remove cores from service valves (if not already done).
Close manifold gauge valves.
Shut off HFC-410A cylinder.
Reinstall service valve cores by removing manifold hose from service valve. Quickly install cores with core
tool while maintaining a positive system pressure.
Replace stem caps and secure finger tight, then tighten an additional one-sixth (1/6) of a turn as illustrated.
FIGURE 10. Evacuating the System

Page 18
IMPORTANT
Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument
capable of accurately measuring down to 50 microns.
WARNING
Possible equipment damage.
Avoid deep vacuum operation. Do not use compressors
to evacuate a system. Extremely low vacuum can cause
internal arcing and compressor failure. Damage caused
by deep vacuum operation will void warranty.
Evacuating the system of non-condensables is critical for
proper operation of the unit. Non-condensables are de-
ned as any gas that will not condense under tempera-
tures and pressures present during operation of an air
conditioning system. Non-condensables and water suc-
tion combine with refrigerant to produce substances that
corrode copper piping and compressor parts.
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 cur-
rent Canadian Electrical Code (CEC).
Refer to the furnace or air handler installation instructions
for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.
24VAC TRANSFORMER
Use the transformer provided with the furnace or air han-
dler for low-voltage control power (24VAC - 40 VA mini-
mum).
WARNING
Electric Shock Hazard. Can cause injury or
death. Unit must be properly grounded in
accordance with national and local codes.
Line voltage is present at all components
when unit is not in operation on units with
single-pole contactors. Disconnect all remote
electric power supplies before opening
access panel. Unit may have multiple power
supplies.
Refer to the unit nameplate for minimum circuit ampacity, and maximum
fuse or circuit breaker (HACR per NEC). Install power wiring and properly
sized disconnect switch.
NOTE — Units are approved for use only with copper conductors.
Ground unit at disconnect switch or to an earth ground.
SIZE CIRCUIT AND INSTALL SERVICE
DISCONNECT SWITCH
NOTE — 24VAC, Class II circuit connections are made in the control
panel.
Install room thermostat (ordered separately) on an inside wall
approximately in the center of the conditioned area and 5 feet (1.5m) from
the floor. It should not be installed on an outside wall or where it can be
affected by sunlight or drafts.
THERMOSTAT
5 FEET
(1.5M)
INSTALL THERMOSTAT
SERVICE
DISCONNECT
SWITCH
MAIN FUSE BOX/
BREAKER PANEL

Page 19
Typical 24VAC Control Wiring Diagrams (Field Installed)
THERMOSTAT INDOOR UNIT
R
C
W1
Y1
O
G
R
C
W1
W2
W3
G
R
C
W1
Y1
O
COMMON
1ST‐STAGE
AUXILIARY
HEAT
INDOOR BLOWER
COMPRESSOR
24V POWER
REVERSING VALVE
COMMON
1ST‐STAGE
AUXILIARY
HEAT
24V POWER
(SOME CONNECTIONS MAY NOT APPLY. REFER
TO SPECIFIC THERMOSTAT AND INDOOR UNIT. )
OUTDOOR UNIT
R
C
W1
Y1
O
G
R
C
W1
W2
W3
G
E
R
C
W1
Y1
O
EMERGENCY
HEAT
EMERGENCY
HEAT RELAY
OUTDOOR
THERMOSTAT
THERMOSTATINDOOR UNIT OUTDOOR UNIT
COMMON
1ST‐STAGE
AUXILIARY
HEAT
INDOOR BLOWER
COMPRESSOR
COMMON
1ST‐STAGE
AUXILIARY
HEAT
REWOPV42REWOPV42
(SOME CONNECTIONS MAY NOT APPLY. REFER TO
SPECIFIC THERMOSTAT AND INDOOR UNIT. )
REVERSING VALVE
WARNING! - ELECTRIC SHOCK HAZARD. Can cause INJURY
or DEATH. Unit must be grounded in accordance with national
and local codes.
NOTE -For use with copper conductors only. Refer to unit rating
plate for minimum circuit ampacity and maximum over‐current
protection size.
FIGURE 11. Typical Control Wiring

Page 20
System Operation
UNIT COMPONENTS
IMPORTANT
Some scroll compressors have an internal vacuum
protector that will unload scrolls when suction pressure
goes below 20 psig. A hissing sound will be heard when
the compressor is running unloaded. Protector will
reset when low pressure in system rises above 40 psig.
DO NOT REPLACE COMPRESSOR.
The outdoor unit and indoor blower cycle on demand from
the room thermostat. If the thermostat blower switch is in
the ON position, the indoor blower operates continuously.
Bi-Flow Liquid line Filter Drier
The unit is equipped with a large-capacity bi-ow lter dri-
er which keeps the system clean and dry. If replacement is
necessary, order another of the same design and capac-
ity. The replacement lter drier must be suitable for use
with HFC-410A refrigerant.
Low Pressure Switch (S87)
The EL15XP1 is equipped with an auto-reset low pressure
switch which is located on the vapor line. The switch shuts
o󰀨 the compressor when the vapor pressure falls below
the factory setting. This switch, which is ignored during
defrost operation, closes at pressures at or above 40 + 5
psig (276 + 34 kPa) and opens at 25 + 5 psig (172 + 34
kPa). It is not adjustable.
Low Pressure Switch Bypass (S41) (Optional)
For use in applications where the heat pump is operated
in outdoor ambient temperatures below 15°F.
• Prevents nuisance trips form the low pressure switch
• Wired in parallel with the low pressure switch
High Pressure Switch (S4)
The EL15XP1 is equipped with an auto-reset high pres-
sure switch (single-pole, single-throw) which is located on
the liquid line. The switch shuts o󰀨 the compressor when
discharge pressure rises above the factory setting. The
switch is normally closed and is permanently adjusted to
trip (open) at 590 + 15 psig (4068 + 103 kPa).
NOTE – A Schrader core is under the pressure switches.
Defrost Thermostat (S6)
The defrost thermostat is located on the liquid line be-
tween the check/expansion valve and the distributor.
When defrost thermostat senses 42°F (5.5°C) or cooler,
the thermostat contacts close and send a signal to the
defrost control to start the defrost timing. It also terminates
defrost when the liquid line warms up to 70°F (21°C).
Crankcase Heater (HR1) and Thermostat Switch (S40)
All models sizes are equipped with a belly band type
crankcase heater. HR1 prevents liquid from accumulating
in the compressor. The HR1 is controlled by a single pole,
single throw thermostat switch (S40) located on the liquid
line. On all units, the heater is on when there is no com-
pressor operation.
Thermal Protection Switch (S173) – Compressor
Mounted
Some EL15XP1 units are equipped with a compressor
mounted normally closed temperature switch that pre-
vents compressor damage due to overheating caused
by internal friction. The switch is located on top of the
compressor casing (see gure 1). This switch senses
the compressor casing temperature and opens at 239-
257°F (115°C-125°C) to shut o󰀨 compressor operation.
The auto-reset switch closes when the compressor cas-
ing temperature falls to 151-187°F (66°C-86°C), and the
compressor is re-energized. This single-pole, single-throw
(SPST) bi-metallic switch is wired in series with the 24V Y
input signal to control compressor operation.
System Conguration
Demand Defrost Control (A108)
The demand defrost control measures di󰀨erential tem-
peratures to detect when the system is performing poorly
because of ice build-up on the outdoor coil. The control
self-calibrates when the defrost system starts and after
each system defrost cycle. The demand defrost control
components are shown in gure 12.
• Demand defrost control connections, jumpers and LED
locations are shown in gure 12.
• Demand defrost control connections, jumpers and LED
descriptions are listed on table 3.
• Demand defrost control status, fault and lockout LEDs
are listed in table 4.