Page 1
WARNING:
HAZARDOUS VOLTAGE - DISCONNECT POWER and DISCHARGE
CAPACITORS BEFORE SERVICING
4YCZ6-IG-8-EN
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WARNING
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18-EB28D1-8-EN
Installer's Guide
Single Packaged Gas/Electric 16 SEER
Convertible, 3 - 5 Ton, 60 - 115 KBTU
R-410A
ALL phases of this installation must comply with NATIONAL, STATE AND LOCAL CODES
IMPORTANT — This Document is customer property. Please return to service information pack and give this Installer's Guide to the homeowner
upon completion of work.
4YCZ6036 through 4YCZ6060
SAFETY HAZARD!
This information is for use by individuals having adequate
backgrounds of electrical and mechanical experience. Any
attempt to repair a central air conditioning product may result
in personal injury and/or property damage. The manufacturer
or seller cannot be responsible for the interpretation of this
information, nor can it assume any liability in connection
with its use.
HAZARDOUS GASSES!
Exposure to fuel substances, or by-products of incomplete
fuel combustion, is believed by the state of California to cause
cancer, birth defects, or other reproductive harm.
This warning complies with State of California law, Proposition 65.
This product must be gas piped by a Licensed Plumber or
Gas Fitter in the Commonwealth of Massachusetts.
HAZARDOUS VOLTAGE, MOVING PARTS, AND GAS!
Bodily injury can result from high voltage electrical components, fast moving fans, and combustible gas. For protection
from these inherent hazards during installation and service,
the electrical supply must be disconnected and the main
gas valve must be turned off. If operating checks must be
performed with the unit operating, it is the technician's responsibility to recognize these hazards and proceed safely.
SAFETY HAZARD!
Do not operate the unit without the evaporator fan or coil
access panels in place. Reinstall the access panels after
performing maintenance proceedures on the fan. Operating
the unit without the access panels properly installed may
result in severe personal injury or death.
Page 2
Installer’s Guide
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CAUTION
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Safety Considerations
IMPORTANT: Read this entire manual before beginning installation procedures.
NOTICE
Warning and Cautions appear at appropriate
locations throughout this guide. Read these
carefully.
WARNING: INDICATES A POTENTIALLY HAZARDOUS SITUATION WHICH, IF NOT AVOIDED,
COULD RESULT IN DEATH OR SERIOUS INJURY.
CAUTION: Indicates a potentially hazardous situation
which, if not avoided, may result in minor or moderate injury. It may also be used to alert against unsafe practices
and where property-damage-only accidents could occur.
This product contains fiberglass wool insulation! Fiberglass
dust and ceramic fibers are believed by the state of California
to cause cancer through inhalation. Glasswool fibers may
also cause respiratory, skin, or eye irritation.
PRECAUTIONARY MEASURES
• Avoid breathing fiberglass dust
• Use a NIOSH approved dust/mist respirator
• Avoid contact with the skin or eyes. Wear long-sleeved,
loose fitting clothing, gloves, and eye protection.
• Wash clothes separately from other clothing, rinse
washer thoroughly.
• Operations, such as sawing, blowing, tear-out, and
spraying may generate fiber concentrations requiring
additional respiratory protection. Use the appropriate
NIOSH approved respirator in these situations.
FIRST AID MEASURES
Eye Contact: Flush eyes with water to remove
dust. If symptoms persist, seek medical
attention.
Skin Contact: Wash affected area gently with soap and
warm water after handling.
EXPLOSION HAZARD!
Propane gas is heavier than air and may collect in any low
areas or confined spaces. In addition, odorant fade may make
the gas undetectable except with a warning device. If the
gas furnace is installed in a basement, an excavated areas
or a confined space, it is strongly recommended to contact
a gas supplier to install a gas detecting warning device in
case of leak. The manufacturer of your furnace does not test
any detectors and makes no representations regarding any
brand or type of detector.
EXPLOSION HAZARD!
To prevent an explosion or possible injury, death, and equipment damage, do not store combustible materials, gasoline,
or other flammable vapors or liquids near the unit.
Page 2
CONTAINS REFRIGERANT!
SYSTEM CONTAINS OIL AND REFRIGERANT UNDER
HIGH PRESSURE. RECOVER REFRIGERANT TO RELIEVE
PRESSURE BEFORE OPENING SYSTEM. Failure to follow
proper procedures can result in personal illness or injury
or severe equipment damage.
RECONNECT ALL GROUNDING DEVICES.
All parts of this product that are capable of conducting
electrical current are grounded. If grounding wires, screws,
straps, clips, nuts, or washers used to complete a path to
ground are removed for service, they must be returned to
their original position and properly fastened.
Unit contains R-410A Refrigerant!
R-410A operating pressure exceeds the limit of R-22. Proper
service equipment is required. Failure to use proper service
tools may result in equipment damage or personal injury.
SERVICE
Use only R-410A Refrigerant and approved POE compres-
sor oil.
Hot Surface!
Do Not touch top of compressor. May cause minor to severe
burning.
Never use combustible cleaning fluids on any part of the
furnace.
Caution must be taken at all times to avoid personal injuries
and/or damage to equipment.
IMPORTANT: This product has been designed and manufactured
to meet ENERGY STAR criteria for energy efficiency. However,
proper refrigerant charge and proper air flow are critical to
achieve rated capacity and efficiency. Installation of this product
should follow the manufacturer’s refrigerant charging and air flow
instructions. Failure to confirm proper charge and airflow may
reduce energy efficiency and shorten equipment life.
IMPORTANT: Do not connect gas piping to the unit until a line pres-
sure test has been completed. This unit should never be exposed to
gas line pressure in excess of 14 inches water column (1/2 PSIG).
The furnace and its equipment shutoff valve must be disconnected
from the gas supply piping system during any pressure testing of
that system at test pressures in excess of 1/2 psi.
IMPORTANT: Reconnect all grounding devices. All parts of this
product capable of conducting electrical current are grounded. If
grounding wires, screws, straps, clips, nuts, or washers used to
complete a path to ground are removed for service, they must be
returned to their original position and properly fastened.
IMPORTANT: Wear appropriate gloves, arm sleeve protectors,
and eye protection when servicing or maintaining this equipment.
IMPORTANT: Air filters and media wheels or plates shall meet the test
requirements in UL 900.
Page 3
Installer’s Guide
Contents
Safety Considerations 2
Introduction 3
Step 1-Inspect Shipment 3
Step 2-Determine Unit Clearances 4
Step 3-Review Location and Recommendation
Information 10
Step 4-Unit Installation 11
Install Flue Hood 11
Ground Level Installation 11
Rooftop Installation -- Curb Mounting 11
Covert Horizontal Airflow to Down Airflow 11
Install Full Perimeter Roof Mounting Curb 11
Lifting and Rigging 12
Placing the Unit on the Mounting Curb 12
Rooftop Installation -- Frame Mounting 13
Rooftop Installation -- No Frame/Curb 13
Ductwork Installation 16
Attaching Downflow Ductwork to Roof Curb 16
Attaching Downflow Ductwork to Roof Frame 16
Attaching Horizontal Ductwork to Unit 16
Condensate Drain Piping 16
Gas Piping Installation 16
Pipe Delivery Schedule (natural gas only) 17
Gas Pressure Set-up Precautions 17
Gas Supply Line Pressure (all fuels) 17
Verify Manifold Pressure 18
Input Check and Adjustment 18
High Altitude Installation 19
Air Filter Installation 19
Electrical Wiring 19
Electrical Connections 18
Electrical Power 19
Disconnect Switch 19
Over current Protection 19
Power Wiring 19
Control Wiring (Class II) 20
Thermostat Heat Anticipator 20
Step 5-Unit Startup 20
Pre-start Quick Checklist 20
Field Wiring Diagram 21
Starting the Unit in the Cooling Mode 22
Operating Pressures 22
Voltage Check 22
Cooling Shutdown 22
Starting the Unit in Gas Heating Mode 22
Final Installation Checklist 22
Sequence of Operation 23
Maintenance 24
Owner Maintenance 24
Filters 24
Service Maintenance 25
Cooling Season 24
Heating Season 24
Manifold Pressure Check and Adjust 25
Flue Hood and Combustion Blower Cleaning 25
Status LEDs 26
Introduction
Read this manual carefully before attempting to install, operate, or perform maintenance on this unit. Installation and
maintenance should be performed by qualified service technicians only. Do NOT use this furnace for temporary heating of
buildings under construction.
As shipped from the factory, this unit is for use with natural gas
only. It is listed by Underwriters Laboratory. An LP Gas conversion kit is available. Extreme mounting kits for slab and curbs
are also available.
Packedaged units are designed for outdoor mounting with a
vertical condenser discharge. They can be located either at
ground level or on a roof in accordance with local codes or
National Fuel Gas Code (ANSI-Z223.1A) Latest Revision.
Since these units are designed exclusively for outdoor operation, additional flue venting systems are not required. Each
unit contains an operating charge of refrigerant as shipped.
Extreme mounting kits are available for slab (BAYEXMK003A), utility curb (BAYEXMK002B), or curb (BAYEXMK001A) mountings.
This guide is organized as follows:
Step 1- Inspect Shipment
Step 2- Determine Unit Clearances
Step 3- Review Location and Recommendation Information
Step 4- Unit Installation
Step 5- Unit Startup
Sequence of Operation
Maintenance
Step 1—Inspect Shipment
1. Check for damage after the unit is unloaded. Report promptly
to the carrier any damage found to the unit. Do not drop the
unit.
IMPORTANT: To prevent damage to the sides and top of
the unit when hoisting, retain the top shipping skid on the
unit or use “spreader bars” as shown on page 14.
2. Check the unit nameplate to determine if the unit is correct for
the intended application. The power supply must be adequate
for the unit and all accessories.
3. Check to be sure the refrigerant charge has been retained
during shipment. Remove the Compressor access panel to
access the 1/4" flare pressure taps.
4. The Flue Hood is included with the unit's literature pack.
5. If this unit is being installed on a curb, verify that the correct
curb is provided for the unit.
•4YCZ6036 uses model BAYCURB050.
•4YCZ6048 and 4YCZ6060 use model BAYCURB051.
6. If the unit is being hoisted, accessory kit BAYLIFT002B is
recommended. It includes a kit of four (4) lifting lugs and
instructions.
NOTE: If practical, install any internal accessories to the
unit at the shop.
Page 3
Page 4
Installer’s Guide
Step 2—Determine Unit Clearances
Figures 1 through 6 show the unit critical dimensions.
NOTE: The view labeled “Bottom
Side” represents the Base
as viewed looking up from
underneath the unit.
Figure 1. 4YCZ6036 (1 of 3)
Page 4
Page 5
Installer’s Guide
Page 5
Figure 2. 4YCZ6036 (2 of 3)
Page 6
Installer’s Guide
Figure 3. 4YCZ6036 (3 of 3)
Page 6
Page 7
Installer’s Guide
NOTE: The view labeled “Bottom
Side” represents the Base
as viewed looking up from
underneath the unit.
Figure 4. 4YCZ6048 through 4YCZ6060 (1 of 3)
Page 7
Page 8
Installer’s Guide
Figure 5. 4YCZ6048 through 4YCZ6060 (2 of 3)
Page 8
Page 9
Installer’s Guide
Figure 6. 4YCZ6048 through 4YCZ6060 (3 of 3)
Page 9
Page 10
Installer’s Guide
Step 3—Review Location and Recommendation Information
NOTE: The unit is shipped for horizontal installation.
NOTE: During heating operation, avoid supply air below 80
degrees F or return air below 50 degrees F to prevent flue
gas condensation.
Horizontal Airflow Units
1. Location of the unit must allow service clearance around it
to ensure adequate serviceability, maximum capacity, and
peak operating efficiency.
2. These units are designed for outdoor installation. They
may be installed directly on a slab, wood flooring, or on
Class A, B, or C roof covering material. The discharge air
from the condenser fans must be unrestricted for a minimum
of 3 feet above the unit.
3. The louvers above and below the flue hood in the side panel
must have adequate clearance around the air opening into
the combustion area. See Figure 2 on page 5 or Figure 4 on
page 7.
4. Examine all flue product-carrying areas of the furnace, its
vent system, and the main burner for safe operation.
IMPORTANT: A minimum 0” clearance to combustible mate-
rial shall be maintained on air outlet duct.
5. Exhaust vents or other sources of contaminated air must not
be near the unit’s air inlet if outside air is to be introduced
as make-up air or a ventilation feature is to be used. Contamination from exhaust vents or chimneys may also foul the
condenser causing degraded performance.
6. Check the handling facilities to ensure the safety of personnel and the unit(s).
7. The unit must be mounted level for proper drainage of water
through the drain holes in the base pan.
8. The unit should not be exposed to direct roof water runoff.
9. Flexible duct connectors must be of a flame retardant
material. All duct work outside of the structure must be
insulated and weatherproofed in accordance with local
codes.
10. Holes through exterior walls or roof must be sealed in
accordance with local codes.
11. All fabricated outdoor ducts should be as short as possible.
Clearances
1. The recommended clearances for single-unit installations
are illustrated in Figures 1 to 6, pages 4-9.
2. Any reduction of the unit clearances indicated in these
figures may result in condenser coil starvation or the recirculation of warm condenser air. Actual clearances, which
appear to be inadequate should be reviewed with a local
engineer.
3. See the unit’s nameplate for the absolute minimum clearance between the unit and any combustible surfaces.
Down Airflow Units
1. Location of the unit must allow service clearance around it to
ensure adequate serviceability, maximum capacity, and peak
operating efficiency.
2. Refer to the Installation section for instruction on converting
the supply and return airflow covers to down airflow.
3. The field assembled Roof Mounting Curb (BAYCURB050A or
BAYCURB051A) or a field fabricated curb should be in place
before the unit is hoisted to the roof top.
The Roof Mounting Curb (frame) must be installed on a flat,
level section of the roof (maximum of 1/4" per foot pitch) and
provide a level mounting surface for the unit. Also, be sure to
provide sufficient height above the roof to prevent water from
entering the unit.
4. Be sure the mounting curb spans structural members (trusses)
of the roof, thereby providing sufficient support for the weight of
the unit, the curb, the duct(s), and any factory or field installed
accessories.
5. The unit must be mounted level for proper drainage of water
through the drain holes in the base pan.
6. Be sure the hole in the structure for the ducts is large enough
to accommodate the fabricated ducts and the insulation surrounding them. Flexible duct connectors must be of a flame
retardant material. All duct work outside of the structure must be
insulated and weatherproofed in accordance with local codes.
7. Holes through exterior walls or roof must be sealed in accordance with local codes.
8. These units are designed for outdoor installation. They may be
installed directly on a slab, wood flooring, or on Class A, B, or
C roof covering material. The discharge air from the condenser
fans must be unrestricted for a minimum of 3 feet above the
unit.
9. The louvers above and below the flue hood in the side panel
must have adequate clearance around the air opening into the
combustion area.
10. Examine all flue product-carrying areas of the furnace, its vent
system, and the main burner for safe operation.
IMPORTANT: A minimum 0” clearance to combustible material
shall be maintained on air outlet duct.
11. Exhaust vents or other sources of contaminated air should not
be near the unit’s air inlet if outside air is to be introduced as
make-up air or a ventilation feature is to be used. Contamination
from exhaust vents or chimneys may also foul the condenser
causing degraded performance.
12. Check the handling facilities to ensure the safety of personnel
and the unit(s).
Clearances
1. The recommended clearances for single-unit installations are
illustrated in Figures 1 to 6, pages 4-9.
2. Any reduction of the unit clearances indicated in these figures may result in condenser coil starvation or the recirculation of warm condenser air. Actual clearances, which appear
to be inadequate should be reviewed with a local engineer.
3. See the unit’s nameplate for the absolute minimum clearance
between the unit and any combustible surfaces.
Page 10
Page 11
Installer’s Guide
Step 4—Unit Installation
NOTE: The factory ships this unit for horizontal installation.
Install Flue Hood
1. Locate the Flue Hood in the literature package.
2. Remove the two Flue Hood mounting screws from the unit.
They
are located to the right of the Power Entry connection panel.
3. Attach the Flue Hood to the unit with the two screws removed
in
step 2. See Figure 2 on page 5 or Figure 5 on page 8 for correct orientation of the Flue Hood.
Ground Level Installation
To install the unit at ground level:
1. Place the unit on a pad the size of the unit or larger. The unit must
be mounted level for proper drainage of water through the holes
in the base pan. To securely attach the unit to the slab, use
extreme mounting kit, BAYEXMK003A.
The pad must not come in contact with the structure (see Figure
7.) Be sure the outdoor portion of the supply and return air
ducts are as short as possible.
Unit requires vibration support as indicated in Figure 7 below
and in Figure 9 on page 13.
2. The louvers above and below the Flue Hood in the side
panel must have adequate clearance around the air
opening into the combustion area.
3. Location of the unit must allow service clearance around it.
Clearance of the unit must be given careful consideration. See
Figures 1 to 6, pages 4-9.
NOTE: Any reduction of the unit clearances indicated in these
illustrations may result in condenser coil starvation or the
recirculation of warm condenser air. Actual clearances, which
appear to be inadequate should be reviewed with a local
engineer.
4. Attach the supply and return air ducts to the unit as explained
in the following Ductwork Installation section on page 16.
5. Flexible duct connectors must be of a flame retardant material.
Insulate any ductwork outside of the structure with at least two
(2) inches of insulation and weatherproof. There must be a
weather proof seal where the duct enters the structure.
6. Do not expose the unit to direct roof water runoff.
7. Seal all holes through exterior walls in accordance with local
codes.
8. Continue with the following installation sections to complete
the installation: Ductwork on page 16, Gas Piping on page 16,
Filter on page 19, and Electrical Wiring on page 19.
Rooftop Installation -- Curb Mounting
Convert Horizontal Airflow to Down Airflow
The factory ships the unit for horizontal airflow. Perform this
procedure to convert the unit to down airflow:
1. Remove the three (3) sheet metal screws securing the supply
aircover and the four (4) sheet metal screws securing the return
air cover from the base of the unit. Remove the covers from the
base. See Figure 8, page 12.
2. Place the covers over the horizontal supply and return openings (painted side out). Align the screw holes, and secure using
the same screws removed in step 1.
Install Full Perimeter Roof Mounting Curb
1. Verify that the roof mounting curb is correct for the unit. There
are two curbs depending on the unit cabinet sizes:
• 4YCZ6036 uses model BAYCURB050A.
• 4YCZ6048 through 4YCZ6060 use model BAYCURB051A.
2. Assemble and install the curb following the instructions in the
Installer's Guide included with the curb.
IMPORTANT: A minimum 0” clearance to combustible mate-
rial shall be maintained on air outlet duct.
SIDING
RETURN
AIR
DUCT
EXTERIOR
WALL
INSULATE WEATHERPROOF OR RAIN
SHIELD
Figure 7. Typical Ground Level Applications
Page 11
SUPPLY AIR
DUCT
FLEXIBLE DUCT
CONNECTORS
OUTDOOR AIR DISCHARGE
Note: Use the extreme mounting kit, BAYEXMK003A, to
secure the unit to the slab.
SUPPORT PAD FOUNDATION
3/4" VIBRATION ISOLATORS, USE 7 ISOLATORS
AS SHOWN IN FIGURE 9, PAGE 13.
Page 12
Installer’s Guide
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WARNING
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Figure 8. Converting Horizontal to Down Airflow
Lifting and Rigging
Improper Unit Lift!
Test lift unit approximately 24 inches to verify proper center
of gravity lift point. To avoid dropping of unit, reposition
lifting point if unit is not level. Failure to properly lift
unit could result in death or serious injury or possible
equipment or property-only damage.
IMPORTANT: Do not lift the unit without test lifting for balance
and rigging. Do not lift the unit in windy conditions or above
personnel. Do not lift the unit by attaching clevis, hooks, pins,
or bolts to the unit casing, casing hardware, corner lugs, angles,
tabs, or flanges. Failure to observe these warnings may result
in equipment damage.
1. Before preparing the unit for lifting, check the unit dimension
drawings for center of gravity for lifting safety (Figures 1 to 6,
page 4-9). Because of placement of internal components, the
unit’s weight may be unevenly distributed. Approximate unit
weights are also provided in the unit drawings.
NOTE: When unit rigging and hoisting it is recommended that
accessory kit BAYLIFT002B be used. It includes a kit of four
(4) lifting lugs. See Figure 10 inset B, on page 14.
2. Insert the four lifting lugs in the openings provided in the drip lip
on each end of the unit. See Figure 10 inset B on page 14. A
tap or jerk to the lug will overcome the interference that arises
due to the dimple on the lug.
3. When hoisting the unit, be sure that a proper method of rigging
is used. Use either the unit's top shipping skid with straps or
slings and spreader bars for protection during lifting. Always
test-lift the unit to determine the exact unit balance and stability
before hoisting it to the installation location.
4. When the curb and air ducts have been properly installed, the
unit is ready to be hoisted to the roof and set in position.
IMPORTANT: To prevent damage to the sides and top of the
unit when hoisting, retain the top shipping skid on the unit or
use “spreader bars” as shown on page 14.
IMPORTANT: The unit must be lowered into position. The P.V.C.
rubber tape on the curb flange permits the unit to be repositioned
if required without destroying the P.V.C. rubber seal affixed to
the mounting curb.
Placing the Unit on the Mounting Curb
1. The unit is designed with a perimeter drip lip that is lower than
the unit base pan, see Figure 10, inset A, on page 14.
2. Position the unit drip lip down over and in contact with the outside
corner of the curb, as illustrated in Figure 10, inset A, on page
14. Continue to lower the unit on top of the curb, with the unit
drip lip astraddle, and in contact with, both the end and side rail
of the curb. The unit should now rest on top of the curb. Use the
extreme mounting kit, BAYEXMK001A, to add additional hold
down strength to the mounting.
NOTE: The ductwork is installed as part of the curb installation. Do not attach ductwork to the unit and lower the unit with
ductwork onto the curb.
Page 12
Page 13
Installer’s Guide
Small Cabinet
*****018-036
Medium Cabinet
*****042-060
NOTE: These views represent the base as viewed looking up from underneath the unit.
IMPORTANT: Unit requires vibration isolator supports in the general areas shown. Locate 3/4" thick vibration isolators on the
bottom of the basepan as illustrated by black dots for ground level pad applications. Modify vibration isolator location as necessary for frame and rail applications.
Rooftop Installation -- Frame Mounting
For roof top applications using field fabricated frame and ducts, use
the following procedure:
1. Locate and secure the frame to the roof by bolting or welding.
Frame must provide adequate center support via a cross member centrally located channel rail. See Figures 12 and 13 on
page 15. Vibration isolators should be installed as indicated in
Figure 9, adjust as necessary for your frame. The isolators must
be placed on base pan, not drip lip. Add flashing as required.
Flashing must conform to local building codes.
2. Prepare the hole in the roof in advance of installing the unit.
3. Secure the horizontal or down airflow ducts to the roof. Refer
to the previous Convert from Horizontal Airflow to Down Airflow
section on page 11, if conversion is needed.
4. All fabricated outdoor ducts should be as short as possible.
5. Place the unit on the frame. Refer to Figures 12 or 13 on page
14.
6. The unit must be mounted level for proper drainage of water
through the holes in the base pan.
7. Secure the unit to the frame.
8. Insulate any ductwork outside of the structure with at least two
(2) inches of insulation and then weatherproof. There must be
a weatherproof seal where the duct enters the structure.
9. The unit should not be exposed to direct roof water runoff.
10. Flexible duct connectors must be of a flame retardant material.
All duct work outside of the structure must be insulated and
weatherproofed in accordance with local codes.
11. Access and service clearances for the unit must be given careful consideration when locating the duct entrance openings.
Figures 1 to 6, on pages 4-9, provide unit dimensions.
12. Continue with the following installation sections to complete
the installation: Ductwork on page 16, Gas Piping on page 16,
Filter on page 19, and Electrical Wiring on page 19.
Figure 9. Vibration Isolators/Snow Feet Locations
Rooftop Installation -- Flat Roof - No Curb/Frame
For roof top applications using field fabricated ducts and sleeper
rails rather than a curb or frame, use the following procedure:
1. Locate and secure the sleeper rails to the roof. Three (3) sleeper
rails are required. One on each end to support the edges of the
unit and one across the center of the unit. The center rail must
run inside both drip lips. Vibration isolators should be installed
as indicated on Figure 9, adjust as necessary for your sleeper
rails. The isolators must be placed on base pan, not drip lip. Add
flashing as required. Flashing must conform to local building
codes.
2. Prepare the hole in the roof in advance of installing the unit.
3. Secure the horizontal or down airflow ducts to the roof. Refer
to the previous Convert from Horizontal Airflow to Down Airflow
section on page 11, if conversion is needed.
4. All fabricated outdoor ducts should be as short as possible.
5. Place the unit on the rails.
6. The unit must be mounted level for proper drainage of water
through the holes in the base pan.
7. Secure the unit to the rails.
8. Insulate any ductwork outside of the structure with at least two
(2) inches of insulation and then weatherproof. There must be
a weatherproof seal where the duct enters the structure.
9. The unit should not be exposed to direct roof water runoff.
10. Flexible duct connectors must be of a flame retardant material.
All duct work outside of the structure must be insulated and
weatherproofed in accordance with local codes.
11. Access and service clearances for the unit must be given careful consideration when locating the duct entrance openings.
Figures 1 to 6, on pages 4-9, provide unit dimensions.
12. Continue with the following installation sections to complete
the installation: Ductwork on page 16, Gas Piping on page 16,
Filter on page 19, and Electrical Wiring on page 19.
Page 13
Page 14
Installer’s Guide
Base of unit
rest on top of
curb rails
Drip lip on
perimeter of
unit
Spreader Bars
IMPORTANT: To prevent damage
to the sides and top of the unit when
hoisting, retain the top shipping skid
on the unit or use “spreader bars” as
shown in these illustrations.
Top shipping skid attached to unit
Gasket Seal
Figure 10. Lifting and Rigging
Drip Lip
Dimple
BAYLIFT002A
Lifting Lugs
This drawing was prepared by the manufacturer in order to provide detail regarding job layout only. This drawing is not
intended to be used as a basis to construct, build or modify the item depicted in the drawing. The manufacturer is not
responsible for the unauthorized use of this drawing and expressly disclaims any liability for damages resulting from
such unauthorized use.
Figure 11. Curb Dimensions
Page 14
Page 15
Roof Flashing
Installer’s Guide
Supply Air
Return Air
Channel Iron Center
Support (Center Support required on all
Frame Applications.)
Angle Iron Frame
Figure 12. Typical Rooftop Horizontal Airflow Application with Frame
Supply Air
Return Air
Roof Flashing
Figure 13. Typical Rooftop Down Airflow Application with Frame
Page 15
Channel Iron Center Support
(Center Support required on all
Frame Applications.)
Roof Flashing
Angle Iron Frame
Page 16
Installer’s Guide
▲
WARNING
!
FIELD DUCT
UNIT DUCT
FLANGE
UNIT BASE
AIR PROOF
THIS SEAM
FIELD DUCT
UNIT DUCT
FLANGE
UNIT BASE
AIR PROOF
THIS SEAM
FIELD
DUCT
UNIT DUCT FLANGE
UNIT BASE
AIR PROOF
THIS SEAM
FIELD DUCT
UNIT DUCT
FLANGE
UNIT BASE
NOT RECOMMENDED
WATERPROOF SEAM
WITH BUTYL OR
SILICONE
FIELD DUCT
UNIT EXTERIOR
WEATHERPROOF
THIS SEAM
FIELD DUCT
UNIT EXTERIOR
WEATHERPROOF
THIS SEAM
3
/4" PVC OR COPPER
TUBING AND FITTINGS
1-1/2"
MIN.
1-1/2"
MIN.
Ductwork Installation
Attaching Downflow Ductwork to Roof Curb
Supply and return air flanges are provided on the BAYCURB050
and BAYCURB051 model roof curbs for easy duct installation. All
ductwork must be run and attached to the curb before the unit is
set into place.
Attaching Downflow Ductwork to Roof Frame
Follow these guidelines for ductwork construction:
Connections to the unit should be made with three (3) inch canvas
connectors to minimize noise and vibration transmission.
Elbows with turning vanes or splitters are recommended to minimize
air noise and resistance.
The first elbow in the ductwork leaving the unit should be no closer
than two (2) feet from the unit to minimize noise and resistance.
To prevent leaking, do not attach the ductwork to the bottom of the
unit base; refer to the bottom example in Figure 14.
Figure 15. Horizontal Airflow Ductwork
Condensate Drain Piping
A 3/4-inch female NPT condensate drain connection is provided on
the filter access panel end of the unit. Provide a trap and fill it with
water before starting the unit to avoid air from being drawn through.
Follow local codes and standard piping practices when running the
drain line. Pitch the line downward away from the unit. Avoid long
horizontal runs. See Figure 16.
Figure 14. Down Airflow Ductwork
Attaching Horizontal Ductwork to Unit
All conditioned air ductwork should be insulated to minimize heating
and cooling duct losses. Use a minimum of two (2) inches of insulation
with a vapor barrier. The outside ductwork must be weatherproofed
between the unit and the building.
When attaching ductwork to a horizontal unit, provide a flexible
watertight connection to prevent noise transmission from the unit
to the ducts. The flexible connection must be indoors and made
out of heavy canvas.
NOTE: Do not draw the canvas taut between the solid ducts.
NOTE: Do not use reducing fittings in the drain lines.
The condensate drain must be:
● Made of 3/4" pipe.
● Pitched 1/4" per foot to provide free drainage to convenient drain
system.
● Trapped.
● Must not be connected to a closed drain system unless the trap
is properly vented.
Figure 16. Typical Condensate Drain Piping
Gas Piping Installation
FIRE OR EXPLOSION HAZARD!
Failure to follow the safety warning exactly could result in
serious injury, death, or property damage. Never test for
gas leaks with an open flame. Use a commercially available
soap solution made specifically for the detection of leaks to
check all connections. A fire or explosion may result causing
property damage, personal injury or loss of life.
Page 16
Page 17
IMPORTANT: Before making the gas pipe connection give serious
DEALER INSTALLED
GROUND UNION
1/8" N.P.T.PLUGGED
ACCESS FOR TEST
GAUGE CONNECTION
FROM
GAS SUPPLY
FIELD SUPPLIED MAIN
GAS VALVE, MUST BE
INSTALLED BY DEALER
OUTSIDE OF UNIT.
UNIT
TO MAIN
CONTROL
VALVE
6"
MIN
DRIP LEG
(6" MIN)
Furnace Input in BTUH
Gas Heat Contne in BTU/Cu. Ft. X Multiplier
CFH =
consideration to providing the clearance necessary to remove the
access panels on the unit (e.g., economizer and filter access panels).
NOTE: In the absence of local codes, the installation must conform with American National Standard--Z223.1--National Fuel
Gas Code, Latest Revision.
The available gas supply must agree with the required gas supply
marked on the unit nameplate. Minimum permissible gas supply
pressure for purpose of input adjustment must be at least 7.0 in. w.
c. (inches water column) for natural gas and 11 in. w. c. for LP Gas.
Pipe Delivery Schedule
NOTE: The following procedure and tables apply to Natural
Gas only.
1. Obtain from the gas company the heating value and specific
gravity of the gas delivered.
2. Determine the exact length of pipe needed.
3. Read BTUH input nameplate on the furnace.
4. Use the multiplier opposite the specific gravity of the gas given
in Table 1 below and insert in the following formula:
5. Using Table 2, select the pipe length nearest to calculated size.
Installer’s Guide
Gas Pressure Set-up Precautions
IMPORTANT: Do not connect gas piping to the unit until a line
pressure test has been completed. This unit should never be
exposed to gas line pressure in excess of 14 inches water column
(1/2 PSIG). The furnace and its equipment shutoff valve must be
disconnected from the gas supply piping system during any pressure testing of that system at test pressures in excess of 1/2 psi.
The furnace must be isolated from the gas supply piping system
by closing its individual manual shut-off valve during any pressure
testing of the gas supply piping system at test pressures less than
or equal to 1/2 psig (3.48 kPa).
Gas Supply Line Pressure
Before connecting the unit to the gas supply line, be sure to determine the gas pressure in the line.
If the gas supply pressure is excessive (above 14 inches water
column or 1/2 psig), install a pressure regulator either at the supply
source or in the branch circuit serving the unit. Once the regulator
is installed, set it to provide a pressure of 7 inches water column
with the unit operating and no greater than 14 inches water column
with the unit not operating.
NOTE: Gas pressure in excess of 14 inches water column
(1/2 psig) may damage the regulator, while improper regulation
may result at pressures lower than 5.5 inches water column at
the unit inlet.
6. Follow this line vertically down to the exact CFH found in Step 4
above or the next highest value.
7. Read horizontally to the left of this column for the required pipe
size diameter.
Table 1. Specific Gravity Multiplier
SPECIFIC
GRAVITY
MULTIPLIERS TO BE USED
WHEN THE SPECIFIC GRAV-
ITY OF THE GAS IS OTHER
THAN 0.60
.50 1.10
.55 1.04
.60 1.00
.65 .962
NOTE: If this is an LP Gas application, consult your LP Gas
supplier for pipe sizes and deliveries.
Table 2. Natural Gas Only
TABLE OF CUBIC FEET PER HOUR OF GAS
FOR VARIOUS PIPE SIZES AND LENGTHS
PIPE
SIZE
(inch)
1/2 132 92 73 63 56 50 46
3/4 278 190 152 130 115 105 96
1 520 350 285 245 215 195 180
1-1/4 1050 730 590 520 440 400 370
THIS TABLE IS BASED ON PRESSURE DROP OF 0.3 INCH W.C.
AND 0.6 SP.GR. GAS
Page 17
10 20 30 40 50 60 70
LENGTH OF PIPE (feet)
If the supply line pressure is below the minimum supply pressure
indicated on the unit nameplate, contact the gas supply company.
Follow these steps to complete the installation of the unit gas piping. See Figure 17.
NOTE: The shut-off gas cock must be installed outside of the
unit and should meet the specifications of all applicable national
and local codes.
MULTIPLIER
Figure 17. Gas Pipe
1. Install a tapped, Style A (1/8-inch NPT tap) shut-off gas cock at
the end of the gas supply line near the unit. Be sure the tapped
gas cock is downstream of the pressure regulator, if used.
2. Install a ground union joint downstream of the shut-off cock.
This joint must also be installed outside of the unit.
3. Install a drip leg at least six (6) inches in depth next to the union
as shown in Figure 17. This drip leg is required to collect any
sediment that may be deposited in the line.
Page 18
Installer’s Guide
Chart Flow Reading
2
Chart Flow Reading
4
10X Chart Flow Reading
4
For 1 Cu. Ft. Dial Gas Flow CFH =
For 1/2 Cu Ft. Dial Gas Flow CFH =
For 5 Cu. Ft. Dial Gas Flow CFH =
4. Before connecting the piping circuit to the unit, bleed the air
from the supply line and then cap or plug the line and test the
pressure at the tapped shut-off cock. The pressure reading
should not exceed 14 inches water column.
5. Using an appropriate backup wrench on the gas valve inlet boss,
connect the gas piping to the unit. Check the completed piping
for leaks using a soap and water solution or the equivalent.
6. After installation of the gas pipe in the unit, the pipe opening
should be closed with the filler/barrier plug provided.
Manifold Pressure
Check the manifold pressure at the unit gas valve. Do not exceed
the recommended pressure shown on the unit nameplate.
Input Check and Adjustment
1. Make sure all gas appliances are off except the furnace.
2. Clock the gas meter with the furnace operating (determine the
dial rating of the meter) for one revolution.
3. Match the “Sec” column in the gas flow (in cfh) Table 3, with the
time clocked.
4. Read the “Flow” column opposite the number of seconds
clocked.
5. Use the following factors if necessary.
NOTE: For manifold pressures and orifice sizes for gas with other
BTU ratings, contact the local gas utility. Manifold
pressure should be 1.8 (low) to 3.5 (high) inches water column
(+0.1). Input for natural gas must not exceed the value shown on
the unit nameplate.
6. Multiply the final figure by the heating value of the gas obtained
from the utility company and compare to the nameplate rating.
This must not exceed the nameplate rating.
7. Changes can be made by adjusting the manifold pressure.
a. Attach a manifold pressure gauge.
b. Remove the slot screw on top of the gas valve for 1st stage
manifold pressure adjustment. Remove slot screw on outlet
side for 2nd stage adjustment (See Figure 18).
c. Turn the adjustment nut in to increase the gas flow rate, and
out to decrease the gas flow rate using a 3/32" hex wrench.
Table 3. Gas Flow in Cubic Feet Per Hour
2 Cubic Foot Dial
Sec. Flow Sec. Flow Sec. Flow Sec. Flow
8 900 29 248 50 144 82 88
9 800 30 240 51 141 84 86
10 720 31 232 52 138 86 84
11 655 32 225 53 136 88 82
12 600 33 218 54 133 90 80
13 555 34 212 55 131 92 78
14 514 35 206 56 129 94 76
15
480 36
16 450 37 195 58 124 98 73
17 424 38 189 59 122 100 72
18 400 39 185 60 120 104 69
19 379 40 180 62 116 108 67
20 360 41 176 64 112 112 64
21 343 42 172 66 109 116 62
22 327 43 167 68 106 120 60
23 313 44 164 70 103 124 58
24 300 45 160 72 100 128 56
25 288 46 157 74 97 132 54
26 277 47 153 76 95 136 53
27 267 48 150 78 92 140 51
28 257 49 147 80 90 144 50
200 57
126
96 75
2nd Stage (HI)
Outlet Pressure Boss
Inlet Pressure Boss
Gas Valve
ON/OFF
Toggle
Switch
High Fire Coil
Terminal (H)
Page 18
Manifold Pressure
Adjustment
Regulator
Vent
1st Stage
(LO)
Manifold
Pressure
Adjustment
Coaxial Coil
Terminal (M)
Common
Terminal (C)
Figure 18. Burner and Valve
Page 19
High Altitude Installation
Unit Input
115k 2001 3000 4000 5000 6000 7000 8000
High stage
112100 104100 96200 88100 86900 85600 85100
Low stage
84000 78100 72100 66100 65100 64200 63800
90k
High stage
87700 81500 75200 69000 68000 67000 66500
Low stage
65700 61100 56400 51700 51000 50200 49900
70k
High stage
68200 63300 58500 53600 52900 52100 51800
Low stage
51100 47600 43900 40200 39600 39100 38800
60k
High stage
58500 54300 50100 46000 45300 44700 44300
Low stage
43800 40700 37600 34500 34000 33400 33200
For LP installations. Models that require #49 orifices, for
altitudes from 7000 - 8000' orifices must be changed to #50.
HIGH ALTITUDE DERATE CHART NAT.
Altitude (In Feet)
Inputs shown are with factory orifices @ 3.5"WC (High Fire)
1.8"WC (Low Fire)
Natural Gas heating value of 950 btu/cuft.
▲
WARNING
!
UNIT
NOMINAL
CFM
FILTER* SIZE
(Sq. Ft.)
FILTER
RESISTANCE
(
"W.C."
)
4YCZ6036 1200 4 0.08
4YCZ6048 1600 5.33 0.08
4YCZ6060 2000 6.67 0.08
Unit nameplate ratings are based on equipment operation from
sea level to 2000 feet elevation above sea level. No orifice changes
required for high altitude installation, please refer to below chart for
rating information.
Table 4. High Altitude Derate Chart
Installer’s Guide
NOTE: This unit is factory wired for 230V. See wiring diagram in SERVICE FACTS for 208V conversion.
Electrical Connections
Electrical wiring and grounding must be installed in accordance
with local codes or, in the absence of local codes, with the National
Electrical Code ANSI/NFPA 70, Latest Revision.
NOTE: For branch circuit wiring (main power supply to unit
disconnect), determine wire size for the length of run using the
circuit ampacity found on the unit nameplate and the N.E.C.
For more than 3 conductors in a raceway or cable, see the
N.E.C. for derating the ampacity of each conductor.
Run power
supply Lines
through weather-tight conduit
and secure to
unit with strain
relief
Air Filter Installation
The packaged unit requires an air filter. The unit does not come
with a factory installed filter rack in it, however, two filter frame accessories are offered that will allow the installation of a filter within
the unit, BAYFLTR101 & BAYFLTR201. Otherwise a field supplied
filter rack must be installed by the installer in the return duct work.
Refer to Table 5 to determine filter sizes for field supplied filter racks.
Table 5. Filter Sizes (field supplied filter rack)
*Filters must be installed in the return air system. The above square
footages are based on 300 F.P.M. face velocity. If permanent filters are
used, size per mfg. Recommendation with clear resistance of 0.05" W.C.
IMPORTANT: Air filters and media wheels or plates shall meet the test
requirements in UL 900.
Electrical Wiring
HAZARDOUS VOLTAGE, MOVING PARTS, AND GAS
Bodily injury can result from high voltage electrical components, fast moving fans, and combustible gas. For protection
from these inherent hazards during installation and service,
the electrical supply must be disconnected and the main
gas valve must be turned off. If operating checks must be
performed with the unit operating, it is the technician's responsibility to recognize these hazards and proceed safely.
Page 19
Figure 19. Power Wiring
Electrical Power
It is important that proper electrical power be available for the unit.
Voltage variation should remain within the limits found on the unit
nameplate.
Disconnect Switch
Provide an approved weatherproof disconnect within close proximity and within sight of the unit. If disconnect must be mounted
to the cabinet, the location shown in Figure 21 should be the only
one considered.
Over Current Protection
The branch circuit feeding the unit must be protected as shown on
the unit nameplate.
Power Wiring
The power supply lines must be run in weather-tight conduit to the
disconnect and into the side of the unit control box. Provide strain
relief for all conduit with suitable connectors.
Provide flexible conduit supports whenever vibration transmission
may cause a noise problem within the building structure.
1. Remove the CONTROL/HEAT access panel. Pass the power
wires through the Power Entry hole in the end of the unit.
See Figure 19.
2. Connect the high voltage wires to the appropriate contactor lug
terminals. Single phase units use a two (2) pole contactor
and three phase units use two (2) pole contactor and a Blue
lead wire. Connect the ground to the ground lug on the chassis. See Figure 20. Be sure all connections are tight.
GROUNDING: THE UNIT MUST BE ELECTRICALLY
GROUNDED IN ACCORDANCE WITH LOCAL CODES OR
THE NATIONAL ELECTRIC CODE.
NOTE: Unit must be grounded for ignitor to operate properly.
Gas pipe to unit is not an adequate ground. Ground the unit
internally as provided.
Page 20
Installer’s Guide
eziSerihWtgneLmumixaM
8517
65121
40102
Contactor
Thermostat Heat Anticipator
Set the heat anticipator of the thermostat to equal the amperage
draw of the gas valve
IMPORTANT: Upon completion of wiring, check all electrical connections, including factory wiring within the unit.
Make sure all connections are tight. Replace and secure all electrical box covers and access panels before leaving the unit or turning
on the power to the unit.
Step 5—Unit Startup
Pre-Start Quick Checklist
● Is the unit properly located and level with the proper clearance?
See Figure 4.
Unit Ground Lug
Figure 20. Power Connections
Figure 21. Mounted Disconnect Location
Control Wiring (Class II)
Low voltage control wiring should not be run in conduit with power
wiring unless Class 1 wire of proper voltage rating is used. Route
the thermostat cable or equivalent single leads of No. 18 AWG
colored wire from the thermostat subbase terminals through the
rubber grommet on the unit. See Figures 2 or 5 for the control
entry (24V Entry) location. Make connections as shown on the
unit wiring diagram.
Do not short thermostat wires since this will damage the control
transformer.
Refer to Table 6 for recommended wire sizes and lengths for installing the unit thermostat. The total resistance of these low voltage
wires must not exceed one (1) ohm. Any resistance in excess of 1
ohm may cause the control to malfunction because of the excessive voltage drop.
● Is the duct work correctly sized, run, taped, insulated, and
weatherproofed with proper unit arrangement? See Ductwork
Installation section.
● Is the gas piping correctly sized, run, trapped, and purged of air?
See Gas Piping section.
● Is the condensate line properly sized, run, trapped, and pitched?
● Is the filter of the correct size and number? Is it clean and in
place?
● Is the wiring properly sized and run according to the unit wiring
diagram?
● Are all the wiring connections, including those in the unit, tight?
● Has the unit been properly grounded and fused with the recom-
mended fuse size? See Wiring Data.
● Is the thermostat level, correctly wired, well located, and set for
the proper heat anticipation?
● Have the air conditioning systems been checked at the service
ports for charge and leak tested if necessary?
● Does the condenser fan and indoor blower turn free without rub-
bing, and are they tight on the shafts?
● Has the indoor blower speed been determined and the proper
speed been set? See the Unit Wiring Diagram.
● Has all work been done in accordance with applicable local and
national codes?
● Are all covers and access panels in place to prevent air loss and
safety hazards?
Table 6. Thermostat Wire Size and Maximum Length
Page 20
Page 21
Installer’s Guide
NOTE: For economizer wiring instructions, see the Installer's Guide that came with your economizer.
Page 21
Figure 22. 4YCZ6 Field Wiring Diagram
Page 22
Installer’s Guide
Starting the Unit in the Cooling Mode
To start the unit in the cooling mode, set the thermostat system switch
to COOL and move the thermostat COOL indicator to a setting below
room temperature. The condenser (outdoor) fan motor compressor
and evaporator (indoor) fan motor will operate automatically.
NOTE: See the section on “Sequence of Operation” for a description of the cooling operating sequence.
Operating Pressures
After the unit has operated in the cooling mode for a short period of
time, install pressure gauges on the gauge ports of the discharge
and suction line valves. Check the suction and discharge pressures
and compare them to the normal operating pressures provided in
the unit’s SERVICE FACTS.
NOTE: Do not use the pressures from the unit's SERVICE FACTS
to determine the unit refrigerant charge. The correct charge is
shown on the unit nameplate. To charge the system accurately,
weigh in the charge according to the unit nameplate.
Voltage
With the compressor operating, check the line voltage at the unit.
The voltage should be within the range shown on the unit nameplate. If low voltage is encountered, check the size and length of
the supply line from the main disconnect to the unit. The line may
be undersized for the length of the run.
Cooling Shut Down
Set the system mode to OFF or adjust the cooling setpoint to above
room temperature.
NOTE: For manifold pressures and orifice sizes for gas with
other BTU ratings, contact the local gas utility. Manifold pressure
should be 1.8 (low) to 3.5 (high) inches water column (+0.1).
Input must not exceed the value shown on the unit nameplate.
6. Set the heat anticipator of the thermostat to equal the amperage
draw of the gas valve, approximately 0.7.
7. Set the thermostat at the desired temperature setting and the
unit will function automatically.
Starting the Unit in the Gas Heating Mode
1. Check to make sure all grilles and registers are open and all
unit access doors are closed before start-up.
2. Purge the gas supply line of air by opening the union ahead of
the unit. When the odor of gas is detected, retighten the union
and wait five (5) minutes before proceeding.
3. Set the wall thermostat to its lowest position and place the fan
switch in the AUTO or ON position.
4. Open the main gas valve(s) and turn on the unit power supply.
5. Reset the heating temperature lever on the room thermostat
at the highest value above room temperature. The combustion
blower motor should energize. The main burners should light
within 20-25 seconds. Initial start may be delayed somewhat if
the unit has not been purged and air is trapped in the gas line.
NOTE: Blue smoke produced by the heat exchanger during the
initial burner firing is caused by a thin film of oil on the surface
of the heat exchanger. This oil will burn off quickly.
Heating Cycle
These units are equipped with a solid-state ignition control that lights
the burners each time the thermostat calls for heat. The burners
are extinguished during the OFF cycle.
The gas heating section of the unit can be started using the following procedure:
1. Be sure the thermostat is at its lowest setting and the power to
the unit is off.
a. Turn the main shutoff valve on the gas supply line ON.
b. Turn or switch the manual valve on the combination gas valve
ON position.
2. Be sure the burner compartment access panel is in place.
a. Turn on the electrical power to the unit.
b. Turn the thermostat to the highest setting in the heating cycle.
3. As the thermostat calls for heat, the system cycles as follows:
a. The combustion blower is energized.
b. The pressure switch is closed.
c. The gas valve opens and the ignitor lights the burner.
d. Cycle the thermostat on and off a few times to check out the
control system and burner operation characteristics.
4. With the burners operating, check the manifold pressure with
a manometer. Do not exceed recommended pressures.
Final Installation Checklist
Does the unit run and operate as described in the section on
Sequence of Operation in response to the room thermostat?
Are the condenser fan and indoor blower operating correctly
with proper rotation and without undue noise?
Is the compressor operating correctly and has the system been
checked with a charging chart?
Has the voltage and running current been checked to deter
mine if it is within limits?
Has the thermostat been checked for calibration and the air
discharge grilles adjusted to balance the system?
Has the ductwork been checked for air leaks and
condensation?
Has the furnace manifold pressure been checked and
adjusted if necessary?
Has the heating air temperature rise been checked?
Has the unit been checked for tubing and sheet metal rattles?
Are there any other unusual noises to be checked?
Are all covers and panels in place and properly fastened?
Has the owner been instructed on the proper operation and
maintenance of the unit? Be sure to leave this manual with the
owner.
5. Adjust the unit to obtain an air temperature rise within the range
that is specified on the unit nameplate.
Page 22
Page 23
Installer’s Guide
Sequence of Operation
Operation of the unit heating and cooling cycles is automatic when
the system is set to HEAT or COOL (the optional automatic change-
over thermostat, when set to AUTO, automatically changes to heat
or cool with an appropriate room temperature change). The fan can
be set to ON, causing continuous evaporator (indoor) fan operation
or set to AUTO causing fan operation to coincide with heating or
cooling run cycles. Continuous fan mode during cooling operation
may not be appropriate in humid climates. If the indoor air exceeds
60% relative humidity or simply feels uncomfortably humid, it is
recommended that the fan only be used in the AUTO mode. The fan
switch ON position provides continuous operation while the AUTO
position provides operation during the heating or cooling cycles.
Heating Cycle
Thermostat call for heat ( 2-stage thermostat)
Call for 1st stage only:
(R) and (W1) thermostat contacts close signaling the control
module (IGN) to run its self-check routine. After the control has
verified that the pres sure switch (PS) contacts are open, the
limit switch (TCO) contacts are closed, and the flame rollout (FL)
switch is closed, the induced draft blower (CBM) will be energized
on high speed for approximately 5 seconds.
After the induced draft blower (CBM) has come up to speed,
the control will verify that the pressure switch (PS) contacts are
closed and switch the induced draft blower to low speed for 20
second prepurge. The gas valve (GV) is ener gized in the first
stage to permit gas flow and the spark igniter (IP) is energized.
The flame detector (FD) confirms that igni tion has been achieved
within the 7 second trial period.
As the flame detector confirms that ignition has been achieved
the delay to indoor fan on period begins timing and after
approximately 45 seconds, the indoor blower motor (IDM) will
be energized at low speed and will continue to run during the
heating cycle.
Call for 2nd stage after 1st stage:
(R) and (W2) thermostat contacts close signaling a call for
second stage heat. The induced draft motor (CBM) is energized
on high speed and the gas valve on second stage. After
approximately 30 seconds the control energizes the indoor
blower on high speed.
2nd stage satisfied, 1st stage still called:
(R) and (W2) opens, the induced draft blower is reduced to low
speed the gas valve is reduced to first stage. After about 30
seconds the indoor blower motor is reduced to low speed.
1st stage satisfied:
(R) and (W1) opens, the gas valve (GV) will close. The induced
draft blower (CBM) will be de-energized after approximately 5
seconds postpurge. The indoor blower motor (IDM) will continue
to run for the fan off period (field selectable 60 or 90 seconds [by
jumpers]), then will be de-energized by the control module.
Thermostat call for heat (1-stage Thermostat)
(R) and (W1/W2) (jumped) thermostat contacts close signaling a
call for heat. 1st stage sequence of operation remains the same
as above. 2nd stage heat has a 10 minute delay from the time of
1st stage ignition.
Thermostat satisfied:
(R) and (W1/W2) (jumped) contacts open signaling the control
module to close the gas valve and de-energize the induced
draft blower after approximately 5 second postpurge. The indoor
blower motor will continue to operate at the current speed for 60
or 90 seconds after the flames are extinguished.
Page 23
Safety Sequences
This product is equipped with safety devices to protect against
abnormal conditions.
The temperature limit switch (TCO) is located on the blower barrier,
and can be accessed through the blower compar tment. This automatic
reset device protects against exces sive supply air temperature. If
this device opens, the gas valve is immediately closed and will not
permit operation until the limit switch closes.
The rollout switch (RO) is located in the gas compartment near the
inlet of the burners. This is a manual reset device designed to protect
against any form of flame rollout. If this device is opened the gas
valve is immediately de-energized and the control (IGN) will lockout
the system. The rollout switch (RO) must be reset before operation
is allowed to continue.
The pressure switch (PS) is located in the upper right side of the
gas compartment. This automatic device assures adequate combustion air pressure. If pressure against the induced draft blower outlet
becomes excessive, the pressure switch will react and shut off the
gas valve, until acceptable combustion pressure is again available.
If the control (IGN) does not sense flame within the first trial for ignition period, the gas valve will be de-energized. The control (IGN)
will initiate a 60-second interpurge. Following the interpurge, the
control will perform a second ignition attempt. If the second try is
not successful, the control will start another 60-second interpurge.
After the interpurge, a third attempt will be tried. If the third try is
not successful, the control will lock out.
If loss of flame occurs during a heating cycle, the control (IGN) will
close the gas valve and cycle through the ignition trial as stated above.
If control lock out occurs, the control (IGN) will retry a complete
ignition sequence in 1 hour.
The control (IGN) can be reset by removing power to the unit or
by turning the thermo stat from ON to OFF for approximately three
seconds, then back ON.
Cooling Cycle
Thermostat call for cooling (2-stage thermostat)
Call for 1st stage cooling only:
With the room thermostat set to the COOL position and the fan
switch in the AUTO position, a call for cooling will supply power
to the unit from the room thermostat (Y1) and (G) terminal.
(Y1) provides power to the compressor contactor (CC). The
energized compressor contactor (CC) completes the circuit to the
compressor for 1st stage (Low) operation and the outdoor single
speed fan motor (ODM). (G) provides power to the (ECMC) for
low speed (IDM) indoor fan motor operation.
The thermostat will continue to cycle the compressor and fans to
maintain the desired temperature.
Call for 2nd stage after 1st stage
On a call for 2nd stage cooling, power is supplied from the room
thermostat (Y2) terminal to the compressor rectifier (ACR) and
the (ECMC). This energizes the (ACR) switching the compressor
to 2nd stage (High) operation. With the compressor’s internal
solenoid energized, both unloading orifices are closed enabling
the compressor to pump at full rated capacity. The (ECMC) is
energized for indoor fan motor (ECM) high speed fan operation.
The room thermostat will continue to cycle the system between
1st and 2nd stage to maintain the desired temperature without any
cycling time delays in operation.
Page 24
Installer’s Guide
CFM
SELECTION
LIGHT
DIP
SWITCHES
▲
WARNING
!
ECM Fan Motor Adjustments
If the airflow needs to be increased or decreased, see the
Airflow Table in the SERVICE FACTS. Information on changing the speed of the blower motor is in the Blower Performance
Table. Blower speed changes are made on the ECM Fan Control
mounted in the control box. The ECM Fan Control controls the
variable speed motor. There is a bank of 8 dip switches, (See
Figure 20 below), located on the board. The dip switches work in
pairs to match the cooling/heat airflow (CFM/TON), Fan off-delay
options and electric heat airflow adjustment. The unit ships with
dip switches defaulted as shown below.
Maintenance
Owner Maintenance
EXPLOSION HAZARD!
To prevent an explosion or possible injury, death, and equipment damage. Do not store combustible materials, gasoline,
or other flammable vapors or liquids near the unit.
Some of the periodic maintenance functions of the 4YCZ6 unit can
be performed by the owner; this includes replacing the disposable
or cleaning the permanent air filters, cleaning the unit cabinet,
and conducting a general unit inspection on a regular basis.
Filters
When the system is in constant operation, inspect the filters
at least once each month.
If you have disposable-type filters, replace them with new filters
of the same type and size. Do not attempt to clean dispos-
able filters.
Permanent-type filters can be cleaned by washing them with a
mild detergent and water. Make sure that the filters are thoroughly
dry before reinstalling them in the unit (or duct system).
NOTE: It may be necessary to replace permanent filters
annually if washing fails to clean the filter or if the filter shows
signs of deterioration. Be sure to use the same type and
size as was originally installed.
Figure 20. ECM Fan Control
Condenser Coil
Be sure to keep all vegetation and debris away from the condenser
coil area.
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Installer’s Guide
▲
CAUTION
!
Service Maintenance
Service maintenance should be performed by qualified service
personnel.
Cooling Season
To keep the unit operating safely and efficiently, the manufacturer
recommends that a qualified service technician check the entire
system at least once each season or more often if needed. The
service technician should examine these areas of the 4YCZ6 unit:
● filters (for cleaning or replacement)
● motors and drive system components (for proper operation)
● economizer gaskets (for possible replacement)
● safety controls (for mechanical cleaning)
● electrical components and wiring (for possible replacement
and connection tightness)
● condensate drain (for proper sealing and cleaning)
● unit duct connections (to see that they are physically sound
and sealed to the unit casing)
● unit mounting support (for structural integrity)
● the unit (for obvious unit deterioration)
Heating Season
Complete the following unit inspections and service routines
described at the beginning of each heating season.
● Visually inspect the unit to ensure that the airflow required
for combustion and condenser coil is not obstructed from the
unit.
● Inspect the control panel wiring to verify that all electrical
connections are tight and that the wire insulation is intact.
● Check the operation of the gas ignition system as follows:
Turn off the gas supply with the unit operating to verify that
the gas valve closes and that a re-ignition cycle is initiated
by the unit.
● Visually inspect the inside of the burners and the burner ports
for deposit buildup and corrosion. Wipe and brush the inside
of the burner and the burner ports and then clean with a dry
cloth. If the deposit buildup or corrosion is excessive, replace
the burners.
Manifold Pressure Check and Adjust
1. Connect a manometer to the pressure tap at the outlet side
of the unit’s gas valve (remove the Control/Heat access
panel). Read the manifold pressure with the burners firing.
See Figure 16 on page 17 for gas valve connections.
2. If the manifold pressure reading does not match the value
indicated on the unit's nameplate, the unit's pressure regulator must be adjusted as follows:
a. Remove the cover screw on the gas regulator located on
the front side of the unit’s gas valve.
b. Turn the adjusting screw clockwise to increase manifold
pressure or counterclockwise to decrease manifold pressure.
3. Check the temperature rise during furnace operation to insure
that it falls within the range specified on the unit's nameplate.
4. If the temperature rise noted is outside of the specified limits,
adjust the indoor air flow to cause the temperature rise of
the heat exchanger to fall within the required range.
Flue Hood and Combustion Blower Cleaning
Never use combustible cleaning fluids on any part of the
furnace.
Before each heating season, the Flue Hood and combustion
blower should be inspected for signs of any blockage or sooting. Any cleaning required should be performed only by a
qualified service technician using the following procedure:
1. Turn the comfort control to OFF. Turn off power to the unit.
Turn the main power disconnect OFF. Turn the manual gas
valve OFF.
2. Remove the Flue Hood from the side panel.
3. Remove the combustion blower from the vestibule panel.
Disconnect blower wiring and pressure switch hose.
4. Wipe blower and Flue Hood clean with a dry cloth.
5. Replace the combustion blower gasket with a new one.
6. Reassemble combustion blower and Flue Hood in reverse
order of removal. Reconnect pressure switch hose.
7. Verify all wiring is correct per the unit's wiring diagram.
8. Follow start-up procedure to place unit back in service. Verify
proper operation.
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Installer’s Guide
Steady OFF Check Power or Failed Board 2 Flashes
System Lockout: Failed to detect or
sustain flame
Slow Flash Rate Normal, No Call for Heat 3 Flashes
Pressure switch problem detected
Fast Flash Rate Not used 4 Flashes
High Limit switch protection device
open
Steady ON Normal, No Call for Heat 5 Flashes
Flame sensed and gas valve not
energized or flame sensed and no "W"
signal
6 Flashes
Flame Rollout Switch open
7 Flashes
Thermostat miswired; W1 & W2
Fast Flash Rate: The LED will flash on for 1/4 second, and off for 1/4 second
Slow Flash Rate: The LED will flash on for 3/4 second, then off for 1/4 second.
The pause between groups of fast flashes is 3 seconds.
Status LED Liteport LED
IGN Diagnostic Indicators Flash Codes
Status LEDs
IGN Board Diagnostic Codes
There are two LEDs on the IGN board that provide status and
diagnostic information. Refer to Table 8 for a description of the
LED codes.
Table 8. IGN LED Diagnostic Indicators *
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Installer’s Guide
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Installer’s Guide
Trane
6200 Troup Highway
Tyler, TX 75707-9010
© 2014 Trane
The manufacturer has a policy of continuous product and product data improvement,
and it reserves the right to change design and specification without notice.
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