Carrier RAS Series Installation and user guide

TABLE OF CONTENTS
SAFETY CONSIDERATIONS 2...................
UNIT ARRANGEMENT AND ACCESS 3...........
SUPPLY FAN (BLOWER) SECTION 4.............
COOLING 6....................................
R−410A REFRIGERANT 8.......................
COOLING CHARGING CHARTS 9................
CONVENIENCE OUTLETS 14....................
SMOKE DETECTORS 15........................
SENSOR AND CONTROLLER 15.................
INDICATORS 20................................
TROUBLESHOOTING 20........................
PROTECTIVE DEVICES 21......................
ELECTRIC HEATERS 21.........................
ECONOMIZER SYSTEMS 24....................
WIRING DIAGRAMS 33.........................
PRE START−UP 35.............................
START−UP, GENERAL 36.......................
OPERATING SEQUENCES 36...................
FASTENER TORQUE VALUES 38................
APPENDIX I. MODEL NUMBER SIGNIFICANCE 38
APPENDIX II. PHYSICAL DATA 39...............
APPENDIX III. FAN PERFORMANCE 39..........
APPENDIX IV. ELECTRICAL DATA 45............
APPENDIX V. MOTORMASTER SENSOR
LOCATIONS 48.................................
UNIT START-UP CHECKLIST 49.................
RAS Series
7.5 to 12.5 Ton
Package Electric Cooling Units
With R−410A Refrigerant
And Micro−channel Condenser Coils
Service and Maintenance Instructions
513 08 3203 00
06/02/10

2
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment
can be hazardous due to system pressure and electrical
components. Only trained and qualified service personnel
should install, repair, or service air-conditioning
equipment. Untrained personnel can perform the basic
maintenance functions of replacing filters. Trained service
personnel should perform all other operations.
When working on air-conditioning equipment, observe
precautions in the literature, tags and labels attached to
the unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for unbrazing operations.
Have fire extinguishers available for all brazing
operations.
Follow all safety codes. Wear safety glasses and work
gloves. Use quenching cloth for brazing operations. Have
fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions attached to
the unit. Consult local building codes and National
Electrical Code (NEC) for special requirements.
Recognize safety information. This is the safety−alert
symbol . When you see this symbol on the unit and in
instructions or manuals, be alert to the potential for
personal injury.
Understand the signal words DANGER, WARNING, and
CAUTION. These words are used with the safety−alert
symbol. DANGER identifies the most serious hazards
which will result in severe personal injury or death.
WARNING signifies a hazard which could result in
personal injury or death. CAUTION is used to identify
unsafe practices which may result in minor personal injury
or product and property damage. NOTE is used to
highlight suggestions which will result in enhanced
installation, reliability, or operation.
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Before performing service or maintenance operations
on unit, turn off main power switch to unit. Electrical
shock and rotating equipment could cause injury.
!WARNING
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Units with convenience outlet circuits may use multiple
disconnects. Check convenience outlet for power
status before opening unit for service. Locate its
disconnect switch, if appropriate, and open it. Tag−out
this switch, if necessary.
!WARNING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal
injury, death and/or equipment damage.
R−410A refrigerant systems operate at higher
pressures than standard R−22 systems. Do not use
R−22 service equipment or components on R−410A
refrigerant equipment.
!WARNING
CUT HAZARD
Failure to follow this caution may result in personal
injury.
Sheet metal parts may have sharp edges or burrs.
Use care and wear appropriate protective clothing,
safety glasses and gloves when handling parts and
servicing air conditioning units.
CAUTION
!

3
UNIT ARRANGEMENT AND ACCESS
General
FIGURE 1 and FIGURE 2 show general unit arrangement
and access locations.
FIGURE 1 Typical Access Panel Location
FILTER ACCESS PANEL
INDOOR COIL ACCESS PANEL
FIGURE 2 Blower Access Panel Location
BLOWER
ACCESS
PANEL
CONTROL BOX
COMPRESSOR
Routine Maintenance
These items should be part of a routine maintenance
program, to be checked every month or two, until a
specific schedule for each can be identified for this
installation:
Quarterly Inspection (and 30 days after initial start)
Return air filter replacement
Outdoor hood inlet filters cleaned
Belt tension checked
Belt condition checked
Pulley alignment checked
Fan shaft bearing locking collar tightness checked
Condenser coil cleanliness checked
Condensate drain checked
Seasonal Maintenance
These items should be checked at the beginning of each
season (or more often if local conditions and usage
patterns dictate):
Air Conditioning
Condenser fan motor mounting bolts tightness
Compressor mounting bolts
Condenser fan blade positioning
Control box cleanliness and wiring condition
Wire terminal tightness
Refrigerant charge level
Evaporator coil cleaning
Evaporator blower motor amperage
Heating
Power wire connections
Fuses ready
Manual−reset limit switch is closed
Economizer or Outside Air Damper
Inlet filters condition
Check damper travel (Economizer)
Check gear and dampers for debris and dirt
Air Filters and Screens
Each unit is equipped with return air filters. If the unit has
an Economizer, it will also have an outside air screen. If a
manual outside air damper is added, an inlet air screen
will also be present.
Each of these filters and screens will need to be
periodically replaced or cleaned.
Return Air Filters
Return air filters are disposable fiberglass media type.
Access to the filters is through the small lift−out panel
located on the rear side of the unit, above the
evaporator/return air access panel. (See Fig. 1.)
To remove the filters:
1. Grasp the bottom flange of the upper panel.
2. Lift up and swing the bottom out until the panel
disengages and pulls out.
3. Reach inside and extract the filters from the filter rack.
4. Replace these filters as required with similar
replacement filters of same size.
To re−install the access panel:
1. Slide the top of the panel up under the unit top panel.
2. Slide the bottom into the side channels.
3. Push the bottom flange down until it contacts the top
of the lower panel (or Economizer top).
IMPORTANT: DO NOT OPERATE THE UNIT WITHOUT
THESE FILTERS!
Outside Air Hood (Optional)
Outside air hood inlet screens are permanent
aluminum−mesh type filters. Check these for cleanliness.
Remove the screens when cleaning is required. Clean by

4
washing with hot low−pressure water and soft detergent
and replace all screens before restarting the unit. Observe
the flow direction arrows on the side of each filter frame.
Economizer Inlet Air Screen
This air screen is retained by spring clips under the top
edge of the hood. (See FIGURE 3.)
FIGURE 3 Filter Installation
22 3/8 (569 mm)
HOOD
DIVIDER
OUTSIDE
AIR
CLEANABLE
ALUMINUM
FILTER
BAROMETRIC
RELIEF FILTER
CAP
FILTER
To remove the filter, open the spring clips. Re−install the
filter by placing the frame in its track, then closing the
spring clips.
Manual Outside Air Hood Screen (Optional)
This inlet screen is secured by a retainer angle across the
top edge of the hood. (See Fig. 4.)
FIGURE 4 Screens Installed on Outdoor Air Hood
(7-1/2 to 10 Ton Shown)
To remove the screen, loosen the screws in the top
retainer and slip the retainer up until the filter can be
removed. Re−install by placing the frame in its track,
rotating the retainer back down and tighten all screws.
SUPPLY FAN (BLOWER) SECTION
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal
injury or death.
Before performing service or maintenance operations
on the fan system, shut off all unit power and tag−out
the unit disconnect switch. Do not reach into the fan
section with power still applied to unit.
!WARNING
Supply Fan (Belt−Drive)
The supply fan system consists of a forward−curved
centrifugal blower wheel on a solid shaft with two
concentric type bearings, one on each side of the blower
housing. A fixed−pitch driven pulley is attached to the fan
shaft and an adjustable−pitch driver pulley is on the
motor. The pulleys are connected using a “V” type belt.
(See Fig. 5.)
FIGURE 5 Belt Drive Motor Mounting
Belt
Check the belt condition and tension quarterly. Inspect the
belt for signs of cracking, fraying or glazing along the
inside surfaces. Check belt tension by using a
spring−force tool (such as Browning’s Part Number “Belt
Tension Checker” or equivalent tool); tension should be
6−lbs at a 5/8−in. deflection when measured at the
centerline of the belt span. This point is at the center of
the belt when measuring the distance between the motor
shaft and the blower shaft.
NOTE: Without the spring−tension tool, place a straight
edge across the belt surface at the pulleys, then deflect
the belt at mid−span using one finger to a 1/2−in.
deflection.
Adjust belt tension by loosening the motor mounting plate
front bolts and rear bolt and sliding the plate toward the
fan (to reduce tension) or away from fan (to increase
tension). Ensure the blower shaft and the motor shaft are
parallel to each other (pulleys aligned). Tighten all bolts
when finished.
To replace the belt:
1. Use a belt with same section type or similar size. Do
not substitute a “FHP” type belt. When installing the
new belt, do not use a tool (screwdriver or pry−bar) to
force the belt over the pulley flanges, this will stress
the belt and cause a reduction in belt life.
2. Loosen the motor mounting plate front bolts and rear
bolts.

5
3. Push the motor and its mounting plate towards the
blower housing as close as possible to reduce the
center distance between fan shaft and motor shaft.
4. Remove the belt by gently lifting the old belt over one
of the pulleys.
5. Install the new belt by gently sliding the belt over both
pulleys and then sliding the motor and plate away
from the fan housing until proper tension is achieved.
6. Check the alignment of the pulleys, adjust if
necessary.
7. Tighten all bolts.
8. Check the tension after a few hours of runtime and
re−adjust as required.
Adjustable−Pitch Pulley on Motor
The motor pulley is an adjustable−pitch type that allows a
servicer to implement changes in the fan wheel speed to
match as−installed ductwork systems. The pulley consists
of a fixed flange side that faces the motor (secured to the
motor shaft) and a movable flange side that can be
rotated around the fixed flange side that increases or
reduces the pitch diameter of this driver pulley. (See Fig.
6.)
FIGURE 6 Supply Fan Pulley Adjustment
As the pitch diameter is changed by adjusting the position
of the movable flange, the centerline on this pulley shifts
laterally (along the motor shaft). This creates a
requirement for a realignment of the pulleys after any
adjustment of the movable flange. Also reset the belt
tension after each realignment.
Check the condition of the motor pulley for signs of wear.
Glazing of the belt contact surfaces and erosion on these
surfaces are signs of improper belt tension and/or belt
slippage. Pulley replacement may be necessary.
To change fan speed:
1. Shut off unit power supply.
2. Loosen belt by loosening fan motor mounting nuts.
(See Fig.5.)
3. Loosen movable pulley flange setscrew. (See Fig.6.)
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified.
5. Set movable flange at nearest keyway of pulley hub
and tighten setscrew to torque specifications.
To align fan and motor pulleys:
1. Loosen fan pulley setscrews.
2. Slide fan pulley along fan shaft. Make angular
alignment by loosening motor from mounting.
3. Tighten fan pulley setscrews and motor mounting
bolts to torque specifications.
4. Recheck belt tension.
Bearings
This fan system uses bearings featuring concentric split
locking collars. The collars are tightened through a cap
screw bridging the split portion of the collar. The cap
screw has a Torx T25 socket head. To tighten the locking
collar: Hold the locking collar tightly against the inner race
of the bearing and torque the cap screw to 65−70 in−lb
(7.4−7.9 Nm). See Fig. 7.
FIGURE 7 Tightening Locking Collar
Motor
When replacing the motor, also replace the external−tooth
lock washer (star washer) under the motor mounting
base; this is part of the motor grounding system. Ensure
the teeth on the lock washer are in contact with the
motor’s painted base. Tighten motor mounting bolts to
120 +/−12 in−lbs.
Changing fan wheel speed by changing pulleys: The
horsepower rating of the belt is primarily dictated by the
pitch diameter of the smaller pulley in the drive system
(typically the motor pulley in these units). Do not install a
replacement motor pulley with a smaller pitch diameter
than provided on the original factory pulley. Change fan
wheel speed by changing the fan pulley (larger pitch
diameter to reduce wheel speed, smaller pitch diameter to
increase wheel speed) or select a new system (both
pulleys and matching belt(s)).
Before changing pulleys to increase fan wheel speed,
check the fan performance at the target speed and airflow
rate to determine new motor loading (bhp). Use the fan
performance tables or use the Packaged Rooftop Builder
software program. Confirm that the motor in this unit is
capable of operating at the new operating condition. Fan
shaft loading increases dramatically as wheel speed is
increased.

6
To reduce vibration, replace the motor’s adjustable pitch
pulley with a fixed pitch pulley (after the final airflow
balance adjustment). This will reduce the amount of
vibration generated by the motor/belt−drive system.
COOLING
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal
injury, death and/or equipment damage.
This system uses R−410A refrigerant which has higher
pressures than R−22 and other refrigerants. No other
refrigerant may be used in this system. Gauge set,
hoses, and recovery system must be designed to
handle R−410A refrigerant. If unsure about equipment,
consult the equipment manufacturer.
!WARNING
Condenser Coil
The condenser coil is new Micro−channel Heat
Exchanger Technology. This is an all−aluminum
construction with louvered fins over single−depth
crosstubes. The crosstubes have multiple small
passages through which the refrigerant passes from
header to header on each end. Tubes and fins are both
aluminum construction with various optional coatings (see
Model Number Format). Connection tube joints are
copper. The coil may be one−row or two−row. Two−row
coils are spaced apart to assist in cleaning.
FIGURE 8 Micro-channel Heat Exchanger Coils
TUBES
FINS
MANIFOLD
MICROCHANNELS
Evaporator Coil
Condenser Coil Maintenance and Cleaning
Recommendation
Routine cleaning of coil surfaces is essential to maintain
proper operation of the unit. Elimination of contamination
and removal of harmful residues will greatly increase the
life of the coil and extend the life of the unit. The following
maintenance and cleaning procedures are recommended
as part of the routine maintenance activities to extend the
life of the coil.
Remove Surface Loaded Fibers
Surface loaded fibers or dirt should be removed with a
vacuum cleaner. If a vacuum cleaner is not available, a
soft non−metallic bristle brush may be used. In either
case, the tool should be applied in the direction of the fins.
Coil surfaces can be easily damaged (fin edges can be
easily bent over and damage to the coating of a protected
coil) if the tool is applied across the fins.
NOTE: Use of a water stream, such as a garden hose,
against a surface loaded coil will drive the fibers and dirt
into the coil. This will make cleaning efforts more difficult.
Surface loaded fibers must be completely removed prior
to using low velocity clean water rinse.
Periodic Clean Water Rinse
A periodic clean water rinse is very beneficial for coils that
are applied in coastal or industrial environments.
However, it is very important that the water rinse is made
with a very low velocity water stream to avoid damaging
the fin edges. Monthly cleaning as described below is
recommended.
Routine Cleaning of Micro−channel Condenser Coil
Surfaces
To clean the Micro−channel condenser coil, chemicals are
NOT to be used; only water is approved as the cleaning
solution. Only clean potable water is authorized for
cleaning Micro−channel condensers. Carefully remove
any foreign objects or debris attached to the coil face or
trapped within the mounting frame and brackets. Using a
high pressure water sprayer, purge any soap or industrial
cleaners from hose and/or dilution tank prior to wetting the
coil.
Clean condenser face by spraying the coil core steadily
and uniformly from top to bottom, directing the spray
straight into or toward the coil face. Do not exceed 900
psig or a 45 degree angle; nozzle must be at least 12 in.
(30 cm) from the coil face. Reduce pressure and use
caution to prevent damage to air centers (fins). Do not
fracture the braze between air centers and refrigerant
tubes. Allow water to drain from the coil core and check
for refrigerant leaks prior to start−up.
NOTE: Please see the Micro−channel Condenser
Service section for specific information on the coil.
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal
injury or equipment damage.
Chemical cleaning should NOT be used on the
aluminum microchannel condenser. Damage to the coil
may occur. Only approved cleaning is recommended.
CAUTION
!

7
Routine Cleaning of Evaporator Coil Surfaces
Monthly cleaning with environmentally sound coil cleaner
is essential to extend the life of coils. This cleaner is
available from FAST parts It is recommended that all
round tube coil cleaner as described below. Coil cleaning
should be part of the unit’s regularly scheduled
maintenance procedures to ensure long life of the coil.
Failure to clean the coils may result in reduced durability
in the environment.
Avoid the use of
coil brighteners
acid cleaning prior to painting
high pressure washers
poor quality water for cleaning
Environmentally sound coil cleaner is non-flammable,
hypoallergenic, non-bacterial, and a USDA accepted
biodegradable agent that will not harm coil or surrounding
components such as electrical wiring, painted metal
surfaces, or insulation. Use of non-recommended coil
cleaners is strongly discouraged since coil and unit
durability could be affected.
Coil Cleaner Application Equipment
2-1/2 gallon garden sprayer
water rinse with low velocity spray nozzle
PERSONAL INJURY HAZARD
Failure to follow this caution may result in corrosion
and damage to the unit.
Harsh chemicals, household bleach or acid or basic
cleaners should not be used to clean outdoor or indoor
coils of any kind. These cleaners can be very difficult
to rinse out of the coil and can accelerate corrosion at
the fin/tube interface where dissimilar materials are in
contact. If there is dirt below the surface of the coil, use
the Totaline environmentally sound coil cleaner as
described above.
CAUTION
!
PERSONAL INJURY HAZARD
Failure to follow this caution may result in reduced unit
performance.
High velocity water from a pressure washer, garden
hose, or compressed air should never be used to clean
a coil. The force of the water or air jet will bend the fin
edges and increase airside pressure drop.
CAUTION
!
Coil Cleaner Application Instructions
1. Proper eye protection such as safety glasses is
recommended during mixing and application.
2. Remove all surface loaded fibers and dirt with a
vacuum cleaner as described above.
3. Thoroughly wet finned surfaces with clean water
and a low velocity garden hose, being careful not
to bend fins.
4. Mix environmentally sound coil cleaner in a 2-1/2
gallon garden sprayer according to the instructions
included with the cleaner. The optimum solution
temperature is 100°F (38°C).
NOTE: Do NOT USE water in excess of 130°F (54°C), as
the enzymatic activity will be destroyed.
5. Thoroughly apply coil cleaner solution to all coil
surfaces including finned area, tube sheets and
coil headers.
6. Hold garden sprayer nozzle close to finned areas
and apply cleaner with a vertical, up−and−down
motion. Avoid spraying in horizontal pattern to
minimize potential for fin damage.
7. Ensure cleaner thoroughly penetrates deep into
finned areas.
8. Interior and exterior finned areas must be
thoroughly cleaned.
9. Finned surfaces should remain wet with cleaning
solution for 10 minutes.
10. Ensure surfaces are not allowed to dry before
rinsing. Reapply cleaner as needed to ensure
10−minute saturation is achieved.
11. Thoroughly rinse all surfaces with low velocity
clean water using downward rinsing motion of
water spray nozzle. Protect fins from damage from
the spray nozzle.
Evaporator Coil Metering Devices
The metering devices are multiple fixed−bore devices
swaged into the horizontal outlet tubes from the liquid
header, located at the entrance to each evaporator coil
circuit path. These are non−adjustable. Service requires
replacing the entire liquid header assembly.
To check for possible blockage of one or more of these
metering devices, disconnect the supply fan contactor
(IFC) coil, then start the compressor and observe the
frosting pattern on the face of the evaporator coil. A frost
pattern should develop uniformly across the face of the
coil starting at each horizontal header tube. Failure to
develop frost at an outlet tube can indicate a plugged or a
missing orifice.
Refrigerant System Pressure Access Ports
There are two access ports in each system −on the
suction tube near the compressor and on the discharge
tube near the compressor. These are brass fittings with
black plastic caps. The hose connection fittings are
standard 1/4 SAE Male Flare couplings.
The brass fittings are two−piece High Flow valves, with a
receptacle base brazed to the tubing and an integral
spring−closed check valve core screwed into the base.
(See Fig.9.) This check valve is permanently assembled
into this core body and cannot be serviced separately.
Replace the entire core body if necessary. Service tools
are available from FAST that allow the replacement of the
check valve core without having to recover the entire
system refrigerant charge. Apply compressor refrigerant

8
oil to the check valve core’s bottom O-ring. Install the fitting body with 96 +/ −10 in−lbs of torque; do not
overtighten.
R−410A REFRIGERANT
This unit is designed for use with R−410A refrigerant. Do
not use any other refrigerant in this system.
R−410A refrigerant is provided in pink (rose) colored
cylinders. These cylinders are available with and without
dip tubes; cylinders with dip tubes will have a label
indicating this feature. For a cylinder with a dip tube, place
the cylinder in the upright position (access valve at the
top) when removing liquid refrigerant for charging. For a
cylinder without a dip tube, invert the cylinder (access
valve on the bottom) when removing liquid refrigerant.
Because R−410A refrigerant is a blend, it is strongly
recommended that refrigerant always be removed from
the cylinder as a liquid. Admit liquid refrigerant into the
system in the discharge line. If adding refrigerant into the
suction line, use a commercial metering/expansion device
at the gauge manifold. Remove liquid from the cylinder,
pass it through the metering device at the gauge set and
then pass it into the suction line as a vapor. Do not
remove R−410A refrigerant from the cylinder as a vapor.
FIGURE 9 CoreMax Access Port Assembly
1/2-20 UNF RH
30
0.596
.47
5/8” HEX
SEAT CORE
WASHER DEPRESSOR PER ARI 720
+.01/-.035
FROM FACE OF BODY
7/16-20 UNF RH
O-RING
45
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.
1/2" HEX
This surface provides a metal to metal seal when
o
o
(Part No. EC39EZ067)
Refrigerant Charge
Amount of refrigerant charge is listed on the unit’s
nameplate. Refer to Recovery, Recycling and
Reclamation training manual and the following
procedures.
Unit panels must be in place when unit is operating during
the charging procedure.
No Charge
Use standard evacuating techniques. After evacuating
system, weigh in the specified amount of refrigerant.
Low−Charge Cooling
Using Cooling Charging Charts, (Fig.10,11,12 and 13)
vary refrigerant until the conditions of the appropriate
chart are met. Note the charging charts are different from
type normally used. Charts are based on charging the
units to the correct superheat for the various operating
conditions. Accurate pressure gauge and temperature
sensing device are required. Connect the pressure gauge
to the service port on the suction line. Mount the
temperature sensing device on the suction line and
insulate it so that outdoor ambient temperature does not
affect the reading. Indoor−air cfm must be within the
normal operating range of the unit.
RAS090−150 Charging
To prepare the unit for charge adjustment:
Disable/bypass all head pressure controls. Start/run both
compressors. On sizes 08 and 12, ensure both condenser
fans are running.
To Use Cooling Charging Charts
Select the appropriate unit charging chart. For size
RAS090 use Fig.10. For size RAS120 use Fig.11. For size
RAS150, use separate charts for each circuit as marked
in Fig.12 and Fig.13.
For Circuit 1: Take the outdoor ambient temperature and
read the Circuit 1 suction pressure gauge. Refer to unit
charging chart to determine what the suction temperature
should be. If suction temperature is high, add refrigerant.
If suction temperature is low, carefully recover some of
the charge. Recheck the suction pressure as charge is
adjusted.
For Circuit 2: Repeat the procedure using “Circuit 2” chart.
EXAMPLE:
Model RAS150
Circuit 1:

9
Outdoor Temperature 85F (29C)............
Suction Pressure 125 psig (860 kPa)..........
Suction Temperature should be 58F (14C)...
Circuit 2:
Outdoor Temperature 85F (29C)............
Suction Pressure 120 psig (830 kPa)..........
Suction Temperature should be 60F (16C)...
Compressors
Lubrication
Compressors are charged with the correct amount of oil at
the factory.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to
components.
The compressor is in a R−410A refrigerant system and
uses a polyolester (POE) oil. This oil is extremely
hygroscopic, meaning it absorbs water readily. POE oils
can absorb 15 times as much water as other oils
designed for HCFC and CFC refrigerants. Avoid
exposure of the oil to the atmosphere.
CAUTION
!
Replacing Compressor
The compressor used with R−410A refrigerant contains a
POE oil. This oil has a high affinity for moisture. Do not
remove the compressor’s tube plugs until ready to insert
the unit suction and discharge tube ends.
Compressor mounting bolt torque is 65−75 in−lbs
(7.3−8.5 Nm).
FIGURE 10 COOLING CHARGING CHARTS 7.5 Tons

10
FIGURE 11 COOLING CHARGING CHARTS 10 Tons

11
Cooling Charging Charts - 12.5 TonFig. 12
Fig. 12 −Cooling Charging Chart (Circuit 1)
Fig. 13 −Cooling Charging Chart (Circuit 2)

12
Compressor Rotation
On 3−phase units with scroll compressors, it is important
to be certain compressor is rotating in the proper
direction. To determine whether or not compressor is
rotating in the proper direction:
1. Connect service gauges to suction and discharge
pressure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge
pressure should rise, as is normal on any start−up.
NOTE: If the suction pressure does not drop and the
discharge pressure does not rise to normal levels:
1. Note that the evaporator fan is probably also........
rotating in the wrong direction.........
2. Turn off power to the unit.........
3. Reverse any two of the unit power leads.........
4. Reapply power to the compressor.........
The suction and discharge pressure levels should now
move to their normal start−up levels.
NOTE: When the compressor is rotating in the wrong
direction, the unit makes an elevated level of noise and
does not provide cooling.
Filter Drier
Replace whenever refrigerant system is exposed to
atmosphere. Only use factory specified liquid−line filter
driers with working pressures no less than 650 psig. Do
not install a suction−line filter drier in liquid line. A
liquid−line filter drier designed for use with R−410A
refrigerant is required on every unit.
Condenser−Fan Location
See Fig.14.
1. Shut off unit power supply. Install lockout tag.
2. Remove condenser−fan assembly (grille, motor, and
fan).
3. Loosen fan hub setscrews.
4. Adjust fan height as shown in Fig.14.
5. Tighten setscrews to 84 in−lbs (9.5 Nm).
6. Replace condenser−fan assembly.
Fig. 14 Condenser Fan Adjustment
Troubleshooting Cooling System
Refer to Table 1 for additional troubleshooting topics.

13
Table 1 −Cooling Service Analysts
PROBLEM CAUSE REMEDY
Compressor and Condenser Fan
Will Not Start.
Power failure. Call power company.
Fuse blown or circuit breaker tripped. Replace fuse or reset circuit breaker.
Defective thermostat, contactor, transformer,
or control relay. Replace component.
Insufficient line voltage. Determine cause and correct.
Incorrect or faulty wiring. Check wiring diagram and rewire correctly.
Thermostat setting too high. Lower thermostat setting below room temperature.
Compressor Will Not Start But
Condenser Fan Runs.
Faulty wiring or loose connections in
compressor circuit. Check wiring and repair or replace.
Compressor motor burned out, seized, or
internal overload open. Determine cause. Replace compressor.
Defective run/start capacitor, overload, start
relay. Determine cause and replace.
One leg of three−phase power dead. Replace fuse or reset circuit breaker. Determine
cause.
Compressor Cycles (other than
normally satisfying thermostat).
Refrigerant overcharge or undercharge. Recover refrigerant, evacuate system, and recharge
to nameplate.
Defective compressor. Replace and determine cause.
Insufficient line voltage. Determine cause and correct.
Blocked condenser. Determine cause and correct.
Defective run/start capacitor, overload, or
start relay. Determine cause and replace.
Defective thermostat. Replace thermostat.
Faulty condenser−fan motor or capacitor. Replace.
Restriction in refrigerant system. Locate restriction and remove.
Compressor Operates
Continuously.
Dirty air filter. Replace filter.
Unit undersized for load. Decrease load or increase unit size.
Thermostat set too low. Reset thermostat.
Low refrigerant charge. Locate leak; repair and recharge.
Leaking valves in compressor. Replace compressor.
Air in system. Recover refrigerant, evacuate system, and recharge.
Condenser coil dirty or restricted. Clean coil or remove restriction.
Excessive Head Pressure.
Dirty air filter. Replace filter.
Dirty condenser coil. Clean coil.
Refrigerant overcharged. Recover excess refrigerant.
Air in system. Recover refrigerant, evacuate system, and recharge.
Condenser air restricted or air short−cycling. Determine cause and correct.
Head Pressure Too Low.
Low refrigerant charge. Check for leaks; repair and recharge.
Compressor valves leaking. Replace compressor.
Restriction in liquid tube. Remove restriction.
Excessive Suction Pressure.
High head load. Check for source and eliminate.
Compressor valves leaking. Replace compressor.
Refrigerant overcharged. Recover excess refrigerant.
Suction Pressure Too Low.
Dirty air filter. Replace filter.
Low refrigerant charge. Check for leaks; repair and recharge.
Metering device or low side restricted. Remove source of restriction.
Insufficient evaporator airflow. Increase air quantity. Check filter and replace if
necessary.
Temperature too low in conditioned area. Reset thermostat.
Outdoor ambient below 25 F. Install low−ambient kit.
Evaporator Fan Will Not Shut
Off. Time off delay not finished. Wait for 30−second off delay.
Compressor Makes Excessive
Noise. Compressor rotating in wrong direction. Reverse the 3−phase power leads.

14
CONVENIENCE OUTLETS
ELECTRICAL OPERATION HAZARD
Failure to follow this warning could result in personal
injury or death.
Units with convenience outlet circuits may use multiple
disconnects. Check convenience outlet for power
status before opening unit for service. Locate its
disconnect switch, if appropriate, and open it. Tag−out
this switch, if necessary.
!WARNING
A non−powered convenience outlet is offered and
provides a125−volt GFCI (ground−fault circuit−interrupter)
duplex receptacle rated at 15−A behind a hinged
waterproof access cover, located on the end panel of the
unit. (See Fig.15.)
Fig. 15 Convenience Outlet Locations
Conv Outlet
GFCI
Weatherproof Cover Installation
A weatherproof while-in-use cover for the factory-installed
convenience outlets is now required by UL standards.
This cover cannot be factory-mounted due to its depth. It
must be installed at unit installation. For shipment, the
convenience outlet is covered with a blank cover plate.
The weatherproof cover kit is shipped in the unit’s control
box. The kit includes the hinged cover, a backing plate
and gasket.
IMPORTANT: DISCONNECT ALL POWER TO UNIT AND
CONVENIENCE OUTLET.
1. Remove the blank cover plate at the convenience
outlet. Discard the blank cover.
2. Loosen the two screws at the GFCI duplex outlet, until
approximately 1/2−in (13 mm) under screw heads are
exposed.
3. Press the gasket over the screw heads.
4. Slip the backing plate over the screw heads at the
keyhole slots and align with the gasket. Tighten the
two screws until snug (do not over-tighten).
5. Mount the weatherproof cover to the backing plate as
shown in Fig.16.
6. Remove two slot fillers in the bottom of the cover to
permit service tool cords to exit the cover.
7. Check for full closing and latching.
Fig. 16 Weatherproof Cover Installation
COVER - WHILE-IN-USE
WEATHERPROOF
BASE PLATE FOR
GFCI RECEPTACLE
Types of Convenience Outlets
Non−Powered Type
This type requires the field installation of a
general−purpose 125−volt 15−A circuit powered from a
source elsewhere in the building. Observe national and
local codes when selecting wire size, fuse or breaker
requirements and disconnect switch size and location.
Route 125−v power supply conductors into the bottom of
the utility box containing the duplex receptacle.
Maintenance
Periodically test the GFCI receptacle by pressing the
TEST button on the face of the receptacle. This should
cause the internal circuit of the receptacle to trip and open
the receptacle. Check for proper grounding wires and
power line phasing if the GFCI receptacle does not trip as
required. Press the RESET button to clear the tripped
condition.
Using Unit−Mounted Convenience Outlets
Units with unit−mounted convenience outlet circuits will
often require that two disconnects be opened to
de−energize all power to the unit. Treat all units as
electrically energized until the convenience outlet power is
also checked and de−energization is confirmed. Observe
National Electrical Code Article 210, Branch Circuits, for
use of convenience outlets.

15
SMOKE DETECTORS
Supply Air Smoke detectors are available as
factory−installed options on RAS models. Smoke
detectors may be specified for Supply Air only or for
Return Air without or with economizer. All components
necessary for operation are factory−provided and
mounted. The unit is factory−configured for immediate
smoke detector shutdown operation; additional wiring or
modifications to unit terminal board may be necessary to
complete the unit and smoke detector configuration to
meet project requirements.
System
The smoke detector system consists of a four−wire
controller and one or two sensors. Its primary function is
to shut down the rooftop unit in order to prevent smoke
from circulating throughout the building. It is not to be
used as a life saving device.
Fig. 17 Controller Assembly
Duct smoke sensor
controller
Fastener
(2X)
Contr oll er cover
Condui t support pl ate
Terminal block cover
Contr oll er housi ng
and electronics
Al arm Power
Test/reset
switch
Trouble
Controller
The controller includes a controller housing, a printed
circuit board, and a clear plastic cover. (See Fig 17.) The
controller can be connected to one or two compatible duct
smoke sensors. The clear plastic cover is secured to the
housing with a single captive screw for easy access to the
wiring terminals. The controller has three LEDs (for
Power, Trouble and Alarm) and a manual test/reset button
(on the cover face).
Sensor
The sensor includes a plastic housing, a printed circuit
board, a clear plastic cover, a sampling tube inlet and an
exhaust tube. (See Fig.18.) The sampling tube (when
used) and exhaust tube are attached during installation.
The sampling tube varies in length depending on the size
of the rooftop unit. The clear plastic cover permits visual
inspections without having to disassemble the sensor.
The cover attaches to the sensor housing using four
captive screws and forms an airtight chamber around the
sensing electronics. Each sensor includes a harness with
an RJ45 terminal for connecting to the controller. Each
sensor has four LEDs (Power, Trouble, Alarm and Dirty)
and a manual test/reset button (on the left−side of the
housing).
Air is introduced to the duct smoke detector sensor’s
sensing chamber through a sampling tube that extends
into the HVAC duct and is directed back into the
ventilation system through a (shorter) exhaust tube. The
difference in air pressure between the two tubes pulls the
sampled air through the sensing chamber. When a
sufficient amount of smoke is detected in the sensing
chamber, the sensor signals an alarm state and the
controller automatically takes the appropriate action to
shut down fans and blowers, change over air handling
systems, notify the fire alarm control panel, etc.
Fig. 18
Duct smoke sensor
Exhaust tube
Pl ug
Sensor housing
and electronics
Exhaust gasket
Coupli ng
Sensor cover
Detail A
Magnetic
test/reset
switch
Al arm
Tr o ub l e
Power
Dirty
See Detail A
Intake
Gasket
TSD−CO2
(ordering option)
Cover Gasket
Sampling tube
(ordered separately)
Smoke Detector Sensor
The sensor uses a process called differential sensing to
prevent gradual environmental changes from triggering
false alarms. A rapid change in environmental conditions,
such as smoke from a fire, causes the sensor to signal an
alarm state, but dust and debris accumulated over time
does not.
For installations using two sensors, the duct smoke
detector does not differentiate which sensor signals an
alarm or trouble condition.

16
Smoke Detector Locations
Supply Air
The Supply Air smoke detector sensor is located to the
left of the unit’s indoor (supply) fan. (See Fig.19.) Access
is through the fan access panel. There is no sampling
tube used at this location. The sampling tube inlet extends
through the side plate of the fan housing (into a high
pressure area). The controller is located on a bracket to
the right of the return filter, accessed through the lift−off
filter panel.
FIOP Smoke Detector Wiring and Response
All Units
FIOP smoke detector is configured to automatically shut
down all unit operations when smoke condition is
detected. See Fig.20, Smoke Detector Wiring.
Highlight A
JMP 3 is factory−cut, transferring unit control to smoke
detector.
Highlight B
Smoke detector NC contact set will open on smoke alarm
condition, de−energizing the ORN conductor.
Fig. 19 Typical Supply Air Smoke Detector Sensor
Location
Smoke Detector Sensor
Highlight C
24−v power signal via ORN lead is removed at Smoke
Detector input on LCTB; all unit operations cease
immediately.
Highlight D
On smoke alarm condition, the smoke detector NO Alarm
contact will close, supplying 24−v power to GRA
conductor.
Highlight E
GRA lead at Smoke Alarm input on LCTB provides 24−v
signal to FIOP DDC control.
Fig. 20
A
E
F
C
D
B
Typical Smoke Detector System Wiring

17
Using Remote Logic
Five conductors are provided for field use (see Highlight
F) for additional annunciation functions.
Additional Application Data — Refer to Catalog No.
HKRNKA−1XA for discussions on additional control
features of these smoke detectors including multiple unit
coordination. (See Fig.20.)
Sensor and Controller Tests
Sensor Alarm Test
The sensor alarm test checks a sensor’s ability to signal
an alarm state. This test requires that you use a field
provided SD−MAG test magnet.
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
This test places the duct detector into the alarm state.
Unless part of the test, disconnect all auxiliary
equipment from the controller before performing the
test. If the duct detector is connected to a fire alarm
system, notify the proper authorities before performing
the test.
CAUTION
!
Sensor Alarm Test Procedure
1. Hold the test magnet where indicated on the side of
the sensor housing for seven seconds.
2. Verify that the sensor’s Alarm LED turns on.
3. Reset the sensor by holding the test magnet against
the sensor housing for two seconds.
4. Verify that the sensor’s Alarm LED turns off.
Controller Alarm Test
The controller alarm test checks the controller’s ability to
initiate and indicate an alarm state.
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in
personnel and authority concern.
This test places the duct detector into the alarm
state. Disconnect all auxiliary equipment from the
controller before performing the test. If the duct
detector is connected to a fire alarm system, notify
the proper authorities before performing the test.
CAUTION
!
Controller Alarm Test Procedure
1. Press the controller’s test/reset switch for seven
seconds.
2. Verify that the controller’s Alarm LED turns on.
3. Reset the sensor by pressing the test/reset switch for
two seconds.
4. Verify that the controller’s Alarm LED turns off.
Dirty Controller Test
The dirty controller test checks the controller’s ability to
initiate a dirty sensor test and indicate its results.
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
Pressing the controller’s test/reset switch for longer
than seven seconds will put the duct detector into the
alarm state and activate all automatic alarm
responses.
CAUTION
!
Dirty Controller Test Procedure
1. Press the controller’s test/reset switch for two
seconds.
2. Verify that the controller’s Trouble LED flashes.
Dirty Sensor Test
The dirty sensor test provides an indication of the
sensor’s ability to compensate for gradual environmental
changes. A sensor that can no longer compensate for
environmental changes is considered 100% dirty and
requires cleaning or replacing. You must use a field
provided SD−MAG test magnet to initiate a sensor dirty
test. The sensor’s Dirty LED indicates the results of the
dirty test as shown in Table 2.
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
Holding the test magnet against the sensor housing for
more than seven seconds will put the duct detector into
the alarm state and activate all automatic alarm
responses.
CAUTION
!
Table 2 Dirty LED Test
FLASHES DESCRIPTION
1 0−25% dirty. (Typical of a newly installed detector)
225−50% dirty
351−75% dirty
476−99% dirty
Dirty Sensor Test Procedure
1. Hold the test magnet where indicated on the side of
the sensor housing for two seconds.
2. Verify that the sensor’s Dirty LED flashes.

18
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
Changing the dirty sensor test operation will put the
detector into the alarm state and activate all automatic
alarm responses. Before changing dirty sensor test
operation, disconnect all auxiliary equipment from the
controller and notify the proper authorities if connected
to a fire alarm system.
CAUTION
!
Changing the Dirty Sensor Test
By default, sensor dirty test results are indicated by:
The sensor’s Dirty LED flashing.
The controller’s Trouble LED flashing.
The controller’s supervision relay contacts toggle.
The operation of a sensor’s dirty test can be changed so
that the controller’s supervision relay is not used to
indicate test results. When two detectors are connected to
a controller, sensor dirty test operation on both sensors
must be configured to operate in the same manner.
To Configure the Dirty Sensor Test Operation
1. Hold the test magnet where indicated on the side of
the sensor housing until the sensor’s Alarm LED turns
on and its Dirty LED flashes twice (approximately 60
seconds).
2. Reset the sensor by removing the test magnet then
holding it against the sensor housing again until the
sensor’s Alarm LED turns off (approximately 2
seconds).
Remote Station Test
The remote station alarm test checks a test/reset station’s
ability to initiate and indicate an alarm state.
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
This test places the duct detector into the alarm state.
Unless part of the test, disconnect all auxiliary
equipment from the controller before performing the
test. If the duct detector is connected to a fire alarm
system, notify the proper authorities before performing
the test.
CAUTION
!
SD−TRK4 Remote Alarm Test Procedure
1. Turn the key switch to the RESET/TEST position for
seven seconds.
2. Verify that the test/reset station’s Alarm LED turns on.
3. Reset the sensor by turning the key switch to the
RESET/TEST position for two seconds.
4. Verify that the test/reset station’s Alarm LED turns off.
Remote Test/Reset Station Dirty Sensor Test
The test/reset station dirty sensor test checks the
test/reset station’s ability to initiate a sensor dirty test and
indicate the results. It must be wired to the controller as
shown in Fig.21 and configured to operate the controller’s
supervision relay. For more information, see “Changing
the Dirty Sensor Test.”
Fig. 21
1
12
14
13
19
15
2
20
3
Reset/Test
Trouble
Power
Alarm
Supervision relay
contacts [3]
5
4
1
3
2
SD-TRK4
2
1
TB3
18 Vdc ( )
+
18 Vdc ( )
−
Auxiliary
equipment
+
−
Wire must be
added by installer
Smoke Detector Controller
Remote Test/Reset Station Connections
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
If the test/reset station’s key switch is left in the
RESET/TEST position for longer than seven seconds,
the detector will automatically go into the alarm state
and activate all automatic alarm responses.
CAUTION
!
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
Holding the test magnet to the target area for longer
than seven seconds will put the detector into the alarm
state and activate all automatic alarm responses.
CAUTION
!
Dirty Sensor Test Using an SD−TRK4
1. Turn the key switch to the RESET/TEST position for
two seconds.
2. Verify that the test/reset station’s Trouble LED
flashes.

19
Detector Cleaning
Cleaning the Smoke Detector
Clean the duct smoke sensor when the Dirty LED is
flashing continuously or sooner if conditions warrant.
OPERATIONAL TEST HAZARD
Failure to follow this caution may result in personnel
and authority concern.
If the smoke detector is connected to a fire alarm
system, first notify the proper authorities that the
detector is undergoing maintenance then disable the
relevant circuit to avoid generating a false alarm.
CAUTION
!
1. Disconnect power from the duct detector then remove
the sensor’s cover. (See Fig.22.)
2. Using a vacuum cleaner, clean compressed air, or a
soft bristle brush, remove loose dirt and debris from
inside the sensor housing and cover.
Use isopropyl alcohol and a lint−free cloth to remove
dirt and other contaminants from the gasket on the
sensor’s cover.
3. Squeeze the retainer clips on both sides of the optic
housing then lift the housing away from the printed
circuit board.
4. Gently remove dirt and debris from around the optic
plate and inside the optic housing.
5. Replace the optic housing and sensor cover.
6. Connect power to the duct detector then perform a
sensor alarm test.
Fig. 22 Sensor Cleaning Diagram
Airow
HVAC duct
Sampling
tube
Retainer
clip
Optic
plate
Optic
housing
Sensor
housing
Table 3 −Detector Indicator
CONTROL OR INDICATOR DESCRIPTION
Magnetic test/reset switch Resets the sensor when it is in the alarm or trouble state. Activates or tests the sensor when it is in the normal
state.
Alarm LED Indicates the sensor is in the alarm state.
Trouble LED Indicates the sensor is in the trouble state.
Dirty LED Indicates the amount of environmental compensation used by the sensor
(flashing continuously = 100%)
Power LED Indicates the sensor is energized.

20
Indicators
Normal State
The smoke detector operates in the normal state in the
absence of any trouble conditions and when its sensing
chamber is free of smoke. In the normal state, the Power
LED on both the sensor and the controller are on and all
other LEDs are off.
Alarm State
The smoke detector enters the alarm state when the
amount of smoke particulate in the sensor’s sensing
chamber exceeds the alarm threshold value. (See Table
3.) Upon entering the alarm state:
The sensor’s Alarm LED and the controller’s Alarm LED
turn on.
The contacts on the controller’s two auxiliary relays
switch positions.
The contacts on the controller’s alarm initiation relay
close.
The controller’s remote alarm LED output is activated
(turned on).
The controller’s high impedance multiple fan shutdown
control line is pulled to ground Trouble state.
The Super Duct duct smoke detector enters the trouble
state under the following conditions:
A sensor’s cover is removed and 20 minutes pass before
it is properly secured.
A sensor’s environmental compensation limit is reached
(100% dirty).
A wiring fault between a sensor and the controller is
detected.
An internal sensor fault is detected upon entering the
trouble state:
The contacts on the controller’s supervisory relay switch
positions. (See Fig. 23.)
If a sensor trouble, the sensor’s Trouble LED the
controller’s Trouble LED turn on.
If 100% dirty, the sensor’s Dirty LED turns on and the
controller’s Trouble LED flashes continuously.
If a wiring fault between a sensor and the controller, the
controller’s Trouble LED turns on but not the sensor’s.
Fig. 23 Controller Assembly
Alarm Power
Test/reset
switch
Trouble
NOTE: All troubles are latched by the duct smoke
detector. The trouble condition must be cleared and then
the duct smoke detector must be reset in order to restore
it to the normal state.
Resetting Alarm and Trouble Condition Trips
Manual reset is required to restore smoke detector
systems to Normal operation. For installations using two
sensors, the duct smoke detector does not differentiate
which sensor signals an alarm or trouble condition. Check
each sensor for Alarm or Trouble status (indicated by
LED). Clear the condition that has generated the trip at
this sensor. Then reset the sensor by pressing and
holding the reset button (on the side) for 2 seconds. Verify
that the sensor’s Alarm and Trouble LEDs are now off. At
the controller, clear its Alarm or Trouble state by pressing
and holding the manual reset button (on the front cover)
for 2 seconds. Verify that the controller’s Alarm and
Trouble LEDs are now off. Replace all panels.
Troubleshooting
Controller’s Trouble LED is On
1. Check the Trouble LED on each sensor connected to
the controller. If a sensor’s Trouble LED is on,
determine the cause and make the necessary repairs.
2. Check the wiring between the sensor and the
controller. If wiring is loose or missing, repair or
replace as required.
Controller’s Trouble LED is Flashing
1. One or both of the sensors is 100% dirty.
2. Determine which Dirty LED is flashing then clean that
sensor assembly as described in the detector
cleaning section.
Sensor’s Trouble LED is On
1. Check the sensor’s Dirty LED. If it is flashing, the
sensor is dirty and must be cleaned.
2. Check the sensor’s cover. If it is loose or missing,
secure the cover to the sensor housing.
3. Replace sensor assembly.
Sensor’s Power LED is Off
1. Check the controller’s Power LED. If it is off,
determine why the controller does not have power
and make the necessary repairs.
2. Check the wiring between the sensor and the
controller. If wiring is loose or missing, repair or
replace as required.
Controller’s Power LED is Off
1. Make sure the circuit supplying power to the controller
is operational. If not, make sure JP2 and JP3 are set
correctly on the controller before applying power.
2. Verify that power is applied to the controller’s supply
input terminals. If power is not present, replace or
repair wiring as required.
Remote Test/Reset Station’s Trouble LED Does Not
Flash When Performing a Dirty Test, But the
Controller’s Trouble LED Does
1. Verify that the remote test/station is wired as shown in
Fig.21. Repair or replace loose or missing wiring.
2. Configure the sensor dirty test to activate the
controller’s supervision relay. See “Changing sensor
dirty test operation.”