Aaon CL-060 Installation Manual

CL SERIES

Condensing Units

Installation, Operation

& Maintenance

Table of Contents

SECTION

Page

GENERAL DESCRIPTION…………………………………………………………………………………………………

Unpacking…………………………………………………………………………………………………………..

05 05

OWNER’S INFORMATION………………………………………………………………………......................................

Wiring Diagrams……………………………………………………………………................................................

General Maintenance………………………………………………………………………………………………..

05 05 06

INSTALLATION…………………………………………………………………………….……………………………....

Lifting and Handling……………………………………….………………………………………………………. Condenser Placement………………………………………………………………………………………………. Compressor Compartment Exhaust Fan……………………………………………………………………………. Mounting Isolation………………………………………………………………………………………………….

Access Doors………………………………………………………………………………………………………. Low Ambient Operation……………………………………………………………………………………………. LAC Valve………………………………………………………………………………………………………….. OROA Valve………………………………………………………………………………………………………... ORI/ORD Valves…………………………………………………………………………………………………… Condenser Flooding………………………………………………………………………………………………… Electrical……………………………………………………………………………………………………………. Refrigerant Piping Connection………………………………………………………………………………………

Evaporative-Cooled Condenser Field Piping Connections………………………………………………………….

06 06 06 06 06 06 07 07 08 08 09 10 10 10

STARTUP……………………………………………………………………………………………………………………

Pre Startup………………………………………………………………………………………………………….. Startup……………………………………………………………………………………………………………… Axial Flow Fans…………………………………………………………………………………………………….

12 12 12 12

SERVICING & MAINTENANCE……………………………………………………………………………………….......

General ……………………………………………………………………………………………………………... Compressors………………………………………………………………………………………………………... Refrigerant Filter Driers…………………………………………………………………………………………….. Evaporator/Heat Exchanger…………………………………………………………………………….…………... Charging Refrigerant ……………………………………………………………………………………………….. Checking Liquid Sub-Cooling……………………………………………………………………………………… Checking Evaporator Superheat……………………………………………………………………………………. Adjusting Sub-cooling and Superheat Temperatures………………………………………………………………. Special Charging Instructions………………………………………………………………………………………. Lubrication……………………………………………………………….……………………………………...….. Service Information…………………………………………………….……………………………………………

14 14 14 14 15 15 15 15 16 16 16 17

EVAPORATIVE-COOLED CONDENSER SECTION……………………………………………………………………... General Information………………………………………………………………………………………………… Pre Start-Up………………………………………………………………………………………………………… Maintenance Recommendations……………………………………………………………………………………. Water Quality……………………………………………………………………………………………………….. AIR-COOLED CONDENSER SECTION…………………………………………………………………………………...

REFRIGERANT PIPING FOR CL SERIES…………………………..………………………………….………..…….......

Equivalent Line Length…………………………………………………………………………………….………. Liquid Line Sizing…………………………………………………………………...……………………………... Suction Line Sizing……………………………………………………………………………………..…………... Hot Gas Bypass Line Sizing..………………………………………………………………….………….………... Predetermined Line Sizes…………………………………………………………………………………………...

TABLE RP-1 Predetermined Line sizes for Dual Circuit CL units with R-410A……………………….…………. TABLE RP-2 Predetermined Line sizes for Dual Circuit CL units with R-22………………………….…………..

TABLE RP-3 Predetermined Line sizes for Single Circuit CL units with R-410A………………….……….. TABLE RP-4 Predetermined Line sizes for Single Circuit CL units with R-22 ……………………….…………..

FIGURE RP-1 Riser height versus total equivalent line length Dual Circuit CL Units with R-410A .….………… FIGURE RP-2 Riser height versus total equivalent line length Dual Circuit CL Units with R-22….. ….………… FIGURE RP-3 Riser height versus total equivalent line length Single Circuit CL Units with R-410A ……………

17 17 19 21 22 23 23 23 23 24 25 26 28 29 30 30 31 31 32

FIGURE RP-4 Riser height versus total equivalent line length Single Circuit CL Units with R-22… …………… Hot Gas Bypass Line Routing Diagrams……………………………………………………………………………

32 33

CL SERIES STARTUP FORM………………………………………………………………………………………………

Literature Change History……………………………………………………………………………………………………..

It is the intent of AAON, Inc. to provide accurate and current specification information. However, in the interest of product improvement, AAON, Inc. reserves the right to change pricing, specifications, and/or

design of its products without notice, obligation or liability

AAON & AAONAIRE are registered trademarks of AAON, Inc., Tulsa, OK.

R10110 · Rev. B · 150727

AAON® CL Series Features and Options Introduction

Energy Efficiency

 Air-Cooled or Energy Saving Evaporative-

Cooled Condenser

 Direct Expansion Systems  Tandem Scroll Compressors  VFD Controlled Condenser Fans

Humidity Control

 Modulating Hot Gas Reheat

Safety

 Phase and Brownout Protection  Automatic Low Pressure and Manual Reset

High Pressure Safety Cut-outs

 Schrader Valves  Internal Overload Protection on Tandem

Scroll Compressors

 Aluminum Tread Plate Floor Covering  Compressor Isolation Valves

Installation and Maintenance

 Access Doors with Hinges, Lockable Handles

and Rain Gutters

 Walk-In Weatherproof Compressor

Compartment

 Run Test Report and Installation Manuals

Included in Controls Compartment

 Color Coded Wiring and Wiring Diagrams  Double Pane Viewing Windows  Compressors are Deck Mounted with Rubber

Isolation

 Three-Chemical Water Treatment System for

Evaporative-Cooled Condenser

 Aluminum Tread Plate Floor  Foam Insulated Double Wall Construction

 Replaceable Core Filter Driers

System Integration

 Single Point Power Connection  Air-Cooled or Evaporative Condensers

Environmentally Friendly

 R-410A Refrigerant

Extended Life

 2,500 Hour Salt Spray Tested Exterior

Corrosion Paint

 Optional 5 Year Non-Prorated Compressor

Warranty

 Sloped Condenser Coils with Outer Protection

GENERAL DESCRIPTION

All AAON 'CL Series' condensers are factory assembled, wired, and charged with 15 lbs. of refrigerant per system. Models are available for air-cooled and evaporative-cooled applications.

Unpacking:

When received, the unit should be checked for damage that might have occurred in transit. If damage is found it should be noted on the

carrier’s Freight Bill. A request for inspection by carrier’s agent should be made in writing at once.

Also, check the unit nameplate to ensure the correct model size and voltage have been received to match the job requirements.

the compressor. Since the compressor is designed to pump refrigerant gas, damage may occur when power is restored.

• Before unit operation, the main power switch

must be turned on for at least twenty four hours for units with compressor crankcase heaters. This will give the crankcase heater time to clear any liquid accumulation out of the compressor before it is required to run.

• Always control the system from the thermostat,

or control panel, never at the main power supply (except for emergency or for complete shutdown of the system).

• Improper installation, adjustment, alteration,

service, or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a qualified installer, service agency or if gas fired units, the gas supplier. Refer to installation instructions provided with the unit and this manual.

• The compressors must be on a minimum of 4 minutes and off for a minimum of 5 minutes. The cycle rate must be no more than 8 starts per hour.

OWNER'S INFORMATION

Warning:

• Failure to observe the following instructions will result in premature failure of your system, and possible voiding of the warranty.

• Never cut off the main power supply to the unit, except for complete shutdown. When power is cut off from the unit, any compressors using crankcase heaters cannot prevent refrigerant migration. This means the compressor will cool down, and liquid refrigerant may accumulate in

The compressor life will be seriously shortened by reduced lubrication, and the pumping of excessive amounts of liquid oil and refrigerant.

Wiring Diagrams:

• A complete set of unit specific wiring diagrams

in both ladder and point-to-point form are laminated in plastic and located inside the control compartment door.

Location

Unit Size

045-135

134-230

Front - Vestibule Door Side

100"

142"

Back - Opposite of Front

100"

142"

Left Side - Condenser End

100"

Right Side - Opposite of Left

100"

Top

UNOBSTRUCTED

OWNER'S INFORMATION cont.

General Maintenance:

When the initial startup is made and on a periodic schedule during operation, it is necessary to perform routine service checks on the performance of the condenser. This includes reading and recording suction pressures and checking for normal sub-cooling and superheat. See the evaporative-cooled condenser and aircooled condenser sections in this manual for specific details.

INSTALLATION

Lifting and Handling:

• If cables or chains are used to hoist the unit

they must be the same length and care should be taken to prevent damage to the cabinet.

• Before lifting unit, be sure that all shipping

material has been removed from unit. Secure hooks and cables at all lifting points/lugs provided on the unit.

• Do not push, pull or lift the unit from anything other than its base.

UNIT MUST BE RIGGED AT ALL

MARKED LIFTING POINTS (Typical)

Condenser Placement:

• The AAON condenser is designed for outdoor applications and mounting at ground level or on a rooftop. It must be placed on a level and solid foundation that has been prepared to support its weight. When installed at ground level, a onepiece concrete slab should be used with footings that extend below the frost line.

• With ground level installation, care must be taken to protect the coil fins from damage due to vandalism or other causes.

• The placement relative to the building air

intakes and other structures must be carefully selected. Be sure to observe the dimensions that are on the rating plate of the condenser for operational and service clearances, which will appear as follows:

Service Clearances

• Condenser coils and fans must be free of any

obstructions in order to start and operate properly with a correct amount of airflow.

• For proper unit operation, the immediate area

around condenser must remain free of debris that may be drawn in and obstruct airflow in the condensing section.

• Consideration must be given to obstruction

caused by snow accumulation when placing the unit.

Compressor Compartment Exhaust Fan:

Prior to unit operation the compressor compartment exhaust fan shipping support MUST BE removed from the exterior of the unit. The exhaust fan also requires the installation of the exterior rain hood provided with the unit.

Mounting Isolation:

• For roof mounted applications or anytime

vibration transmission is a factor, vibration isolators may be used.

Access Doors:

• A lockable access door is provided to the

compressor and electrical compartment.

• A light switch is on the wall of the compressor

control compartment.

INSTALLATION cont.

Low Ambient Operation:

• The AAON low ambient (condenser floodback) system is used to operate a refrigerant system below 25°F outside air temperature. As the ambient temperature drops, the condenser becomes more effective therefore lowering the head pressure. When the head pressure gets too low, there will be insufficient pressure to operate the expansion valve properly. During low ambient temperatures, it is difficult to start a system because the refrigerant will migrate to the cold part of the system (condenser) and make it difficult for refrigerant to flow.

• The AAON low ambient system maintains normal head pressure during periods of low ambient by restricting liquid flow from the condenser to the receiver, and at the same time bypassing hot gas around the condenser to the inlet of the receiver. This backs liquid refrigerant up into the condenser reducing its

capacity that in turn increases the condensing pressure. At the same time the bypassed hot gas raises liquid pressure in the receiver, allowing the system to operate properly.

• There are different types of low ambient control used. The following describe the different systems. Inspect the unit to determine the system used.

LAC Valve:

The LAC valve is a non-adjustable three way valve that modulates to maintain receiver pressure. As the receiver pressure drops below the valve setting (180 psig for R-22 and 295 psig for R-410A), the valve modulates to bypass discharge gas around the condenser. The discharge gas warms the liquid in the receiver and raises the pressure to the valve setting. The following schematic shows an example system using the LAC valve.

Piping Schematic of Example system using the LAC valve.

INSTALLATION cont.

OROA Valve:

This system uses a nonadjustable head pressure control valve that performs the function of limiting the flow of liquid refrigerant from the

condenser and at the same time regulates the flow of the hot gas around the condenser to the receiver. The valve setpoint is 180 psig. This valve is called an OROA valve (Open on Rise of Outlet pressure). The following schematic shows an example system using the OROA valve.

Piping Schematic of Example system using the OROA valve.

ORI/ORD Valves:

This system uses a two-valve arrangement. The head pressure control valve is an inlet pressure regulating valve and responds to changes in condensing pressure. This valve is located in the discharge of the condenser and is called an ORI valve (Open on Rise of Inlet pressure). As the ambient temperature drops, the condenser capacity increases and the condensing pressure falls, causing the ORI to modulate toward the closed position. The condenser bypass valve is a pressure differential valve that responds to changes in the pressure differential across the valve. This valve is called an ORD valve (Open

on Rise of Differential pressure). As the ORI starts to restrict liquid flow from the condenser, a pressure differential is created across the ORD. When the differential reaches the setpoint, the ORD starts to open and bypass hot gas to the liquid line. The ORI valve is adjustable from 65 to 225 psig (factory setting of 180 psig). The ORD is not adjustable. On refrigeration systems that are too large for a single ORI and ORD valve, there will be two ORI and two ORD valves in parallel. The schematic on the following page shows an example system using the ORI/ORD valves.

PERCENTAGE OF CONDENSER TO BE FLOODED

Ambient

Temperature

(°F)

Evaporating Temperature (°F)

0°

10°

20°

30°

35°

40°

45°

50°

70°

24 0 0 0 0 0 0

60°

50°

40°

30°

20°

0°

-20°

INSTALLATION cont.

Piping Schematic of Example system using the ORI/ORD valve.

The pressure setting of the ORI valve determines how well the system will operate. The proper setting is a function of the specific system in which is installed. Generally, the setting should be equivalent to a condensing temperature of 90°F to 100°F or a receiver pressure equivalent to a temperature of 80°F to 90°F. This means that as the ambient temperature falls below 70°F, the head pressure control valve will begin to throttle. To adjust the ORI valve, remove the cap and turn the adjustment screw with the proper size hex wrench (1/4” for ORI-6 and 5/16” for ORI-10). A clockwise rotation increases the valve setting while a counter-clockwise rotation decreases the setting. To obtain the desired setting, a pressure gauge should be used at the compressor discharge service valve so the effects of any adjustment can be observed. Small adjustments are recommended in order to allow the system adequate time to stabilize after each adjustment.

Condenser Flooding:

In order to maintain head pressure in the refrigeration system, liquid refrigerant is backed up in the condenser to reduce condenser surface. The following chart shows the percentage that a condenser must be flooded in order to function properly at the given ambient temperature.

INSTALLATION cont.

During higher ambient temperatures the entire condenser is required to condense refrigerant. During these higher ambient temperatures, a receiver tank is used to contain the refrigerant that was required to flood the condenser during low ambient operation. The receiver must be sized to contain all of the flooded volume otherwise there will be high head pressures during higher ambient conditions.

Electrical:

• The single point electrical power connections are made in the electrical control compartment.

• Check the unit data plate voltage to make sure

it agrees with the power supply. Connect power to the unit according to the wiring diagram provided with the unit.

• The power and control wiring may be brought

up through the utility entry. Protect the branch circuit in accordance with code requirements. Control wires and power should not be run inside the same conduit. The unit must be electrically grounded in accordance with the current National Electric Code.

• Power wiring is to the unit terminal block or main disconnect. All wiring beyond this point has been done by the manufacturer and cannot be modified without effecting the unit's agency/safety certification.

Note: Startup technician must check motor amperage to ensure that the amperage listed on the motor nameplate is not exceeded.

Refrigerant Piping Connections

• CL condensing unit refrigerant piping

connections are located in the upper corner of the

service vestibule side of the unit (opposite the condenser section) as shown in the figure.

• The piping connections are protected with a

shipping cover that must be removed prior to copper connection and installation.

Evaporative-cooled Condenser Field Piping Connections:

• There are two field water connections that must be made for the evaporative-cooled condenser.

There is a ¾” PVC socket city make-up water

connection and a 2” PVC socket drain

connection (as shown on the next page). This drain should connect to a sanitary sewer or other code permitted drain. These connections can go through the base or the wall of the unit.

• There is a cutout in the base with a cap that is

1” tall and the cap is sealed to the unit base to

prevent any leaks in the unit from penetrating into the building. Any piping through the base should go through a field cutout in this cap. The pipes must be sealed to the cap once the piping is complete to prevent any leaks in the unit from penetrating into the building.

• A field cutout must be made in the wall if the evaporative-cooled condenser piping is to go through the unit wall. This cutout must be sealed once the piping is installed to prevent water from leaking into the unit.

Diagram of Evaporative-cooled condenser Section including field water connections and base cutout

tap

STARTUP

Pre-Startup:

After the installation and immediately before the startup of the condenser be sure that these items have been checked.

1. Verify that electrical power is available to the unit.

2. Verify that any remote stop/start device is requesting the condenser to start.

While performing the Startup, use the Condensing Startup Form at the back of this booklet to record motor amps and any other comments.

Startup:

• Use the General Check List at the top of the Startup Form to make a last check that all the components are in place and the power supply is energized.

Note: Condensing fan operation should start with the first compressor.

• Cycle through all the compressors to confirm

that all are operating within tolerance.

• When unit is running, observe the system for a complete operation cycle to verify that all systems are functioning properly.

• While performing the check, use the Condenser Startup Form to record observations of amps and refrigerant pressures.

• When all is running properly, place the controller in the Run mode and observe the system until it reaches a steady state of operation.

Axial Flow Fans:

Multi-Wing Z Series Aluminum Fan Blade Pitch Angle Setting Instructions:

Before You Begin, to maintain balance of fan:

• Mark the hub castings across a joint, so the fan

hub can be reassembled in the same orientation.

• Mark the location of any balancing weight.

Balancing weight will be on the outer bolt circle, in the form of washers, and/or longer bolts, or an additional balancing nut.

• Number the blades and blade sockets, so that

they are replaced into their original position.

• If possible, note the location of the pitch setting

pin in the blade socket, and whether pin is located in the Hub or Retainer half of the fan.

Step 1. Determine Boss Location Code: “A” or

“B” The boss is the center section of the hub

through which the fan is mounted to the shaft, and typically contains either setscrews or a center-tapered hole where the bushing inserts. Select boss location A or B: A is the boss on air inlet, including AS configurations. B is the boss on air discharge, including BS. For flange mounted fans, use boss location A for R rotation fans, and boss location B for L rotation fans.

STARTUP cont.

Step 2. Find Blade Pitch Angle:

( 20, 25, 27.5, 30, 32.5, 35, 37.5, 40, 45 or 50 )

• Carefully disassemble fan on flat surface and

note in which groove the pin is located. Refer to groove number code diagram.

• Using diagrams in step 5, determine if the pin

was in the hub (HUB) or retainer side (RET) of fan.

• Using table in step 4, find the possible blade

pitch.

• Using table in step 3, select your blade angle

based on whether your pin was in the HUB or RET.

Step 3. Determine Hub/Retainer Code: “HUB” or “RET”

Step 4. - Determine Groove Number: 1 or 2 or 3 or 4

Step 5. Final Assembly Definition of HUB and RET for purposes of instructions. For 2-piece hubset:

Using the HUB or RET code found in Step 3:

• If code is HUB, place the hub down on work surface first (one or two pieces, depending on above).

• If code is RET, place one retainer ring only down on the work surface first. (A weighted coffee can could be used to elevate the fan from the work surface).

• Using the groove number, place the locking pin in the groove number that was found in Step 4.

Insert Blades:

• Place the blade over the pin in the hub/retainer

blade socket, so that the pin also fits into the appropriate pitch angle groove in the blade.

• Repeat for all blades.

• Assemble hub set together, aligning the match

marks that were made.

• Replace any balancing weight to its original

position.

STARTUP cont.

• To finish, tighten the bolts in a cross pattern to

5 to 6 ft-lbs of torque.

Multi-Wing W Series Black Glass Reinforced Polypropylene Fan Blade Pitch Angle Setting Instructions:

Step 1. Note original position of retaining plates,

center boss and all hardware including additional hardware used for balancing.

Step 2. Remove all the bolts and nuts.

Step 3. Determine blade rotation – on the

concave side of the blade is a blade marking showing 6WR, 6WL, 7WL, 7WR, or 9WR. The “L” and “R” denote the rotation of the blade.

Step 4. Replace the pitch insert in the blade root with an insert of the desired pitch.

Step 8. Tighten nuts and bolts to 14 ft-lbs of torque.

SERVICING AND MAINTENANCE

General:

• Qualified technicians must perform routine service checks and maintenance. This includes reading and recording the condensing and suction pressures and checking for normal subcooling and superheat (see charging information beginning on page 14).

• Air-cooled and evaporative-cooled condenser units require different maintenance schedules/procedures. Unit specific instructions for both types are included in this manual.

Compressors:

The scroll compressors are fully hermetic and require no maintenance except keeping the shell clean.

Refrigerant Filter Driers:

Each refrigerant circuit contains a replaceable core filter drier. Replacement is recommended when there is excessive pressure drop across the assembly or moisture is indicated in a liquid line sight glass.

Step 5. Replace blades to their original location.

Step 6. Replace all nuts, bolts, and washers on

the fan hub.

Step 7. Replace retaining plates and center boss to original location.

The filter driers are provided with pressure taps and shutoff valves for isolation when changing the core. For safety purposes a service manifold must be attached prior to filter maintenance.

SERVICING AND MAINTENANCE cont.

Evaporator/Heat Exchangers:

Normally no maintenance or service work will be required for a matching direct expansion evaporator with a thermal expansion valve to regulate refrigerant.

Charging Refrigerant:

• Charging a system in the field must be based on determination of liquid sub-cooling and evaporator superheat. On a system with a thermostatic expansion valve liquid sub-cooling is more representative of the charge than evaporator superheat but both measurements must be taken.

Before Charging:

• Refer to the Unit Nameplate to determine the proper refrigerant to charge the system with.

• The unit being charged must be at or near full

load conditions before adjusting the charge.

• Units equipped with hot gas bypass must have

the hot gas bypass valve closed to get the proper charge.

• Units equipped with hot gas reheat must be

charged with the hot gas valve closed while the unit is in cooling mode.

• After adding or removing charge the system

must be allowed to stabilize, typically 10-15 minutes, before making any other adjustments.

• The type of unit and options determine the

ranges for liquid sub-cooling and evaporator superheat. Refer to Table 1 when determining the proper sub-cooling.

• The vertical rise of the liquid line must be

known in order to adjust the sub-cooling range for proper charge.

• Units equipped with low ambient (0°F) option

see special charging instructions at the end of the charging instructions.

Checking Liquid Sub-cooling:

1. Measure the temperature of the liquid line as

it leaves the condenser coil.

2. Read the gauge pressure reading of the liquid line close to the point where the temperature was

taken. You must use liquid line pressure as it will vary from discharge pressure due to condenser coil pressure drop.

3. Convert the pressure obtained in Step 2 to a saturated temperature using the appropriate refrigerant temperature-pressure chart.

4. Subtract the measured liquid line temperature in Step 1 from the saturated temperature in Step 3 to determine the liquid sub-cooling.

5. Compare calculated sub-cooling to TABLE 1. for the appropriate unit type and options.

Checking Evaporator Superheat:

1. Measure the temperature of the suction line

close to the compressor.

2. Read gauge pressure at the suction line close to the compressor.

3. Convert the pressure obtained in Step 2 to a saturated temperature using the appropriate refrigerant temperature-pressure chart.

4. Subtract the saturated temperature in Step 3 from the measured suction line temperature in Step 1 to determine the evaporator superheat.

5. Compare calculated superheat to TABLE 1 for the appropriate unit type and options.

SERVICING AND MAINTENANCE

TABLE 1

Sub-

cooling

(°F)

Superheat

(°F)

Sub-cooling

W/Hot Gas

Reheat (°F)

Air Cooled Condenser

12-18*

8-15**

15-22*

Evaporative

Cooled

Condenser

6-10*

8-15**

8-12*

Water

Cooled

Condenser

6-10*

8-15**

8-12*

cont.

* Sub-cooling must be increased by 3°F per 20 feet of vertical liquid line rise for R-22 and 2°F for R-410A ** Superheat will increase with long suction line runs.

Adjusting Sub-cooling and Superheat Temperatures: The system is overcharged if:

1. the sub-cooling temperature is too high and

2. the evaporator is fully loaded (low loads on

the evaporator result in increased sub-cooling)

and

3. the evaporator superheat is within the

temperature range as shown in TABLE 1 (high superheat results in increased sub-cooling)

Correct an overcharged system by reducing the amount of refrigerant in the system to lower the sub-cooling.

The system is undercharged if:

1. the superheat is too high and

2. the sub-cooling is too low

• Correct an undercharged system by adding refrigerant to the system to reduce superheat and raise sub-cooling.

• If the sub-cooling is correct and the superheat is too high, the TXV may need adjustment to correct the superheat.

Special Charging Instructions:

• For units equipped with low ambient refrigerant flood back option being charged in the summer when the ambient temperature is warm: Once enough charge has been added to get the evaporator superheat and sub-cooling values to the correct setting more charge must be added. Add approximately 80% of the receiver tank volume to the charge to help fill the receiver tank. The additional charge is required for the system when running in cold ambient conditions.

• For units equipped with low ambient refrigerant flood back option being charged in the winter when the ambient temperature is cold:

1. Once enough charge has been added to get the evaporator superheat and sub-cooling values to the correct setting more charge may need to be added. If the ambient temperature is 0°F no more charge is required. If the ambient temperature is around 40°F add approximately 40% of the receiver tank volume.

2. The unit will have to be checked for proper operation once the ambient temperature is above 80°F.

Lubrication:

• All original motors and bearings are furnished

with an original factory charge of lubrication. Certain applications require bearings be relubricated periodically. The schedule will vary depending on operating duty, temperature changes, or severe atmospheric conditions.

• Bearings should be re-lubricated at normal operating temperatures, but not when running.

SERVICING AND MAINTENANCE cont.

Rotate the fan shaft by hand and add only enough grease to purge the seals. DO NOT

OVERLUBRICATE.

Service Information:

If the unit will not operate correctly and a service company is required, only a company with service technicians qualified and experienced in both condensing units and air conditioning are permitted to service the systems to keep warranties in effect. If assistance is required, the service technician must contact AAON.

Replacement Parts

Parts for AAON equipment may be obtained from your local AAON representative. When ordering parts reference the unit serial number and part number.

AAON Warranty, Service and Parts Department

2424 S. Yukon Ave. Tulsa, OK 74107 Ph: 918-583-2266 Fax: 918-382-6364 www.aaon.com

Note: Before calling, technician should have model and serial number of the unit available for the service department to help answer questions regarding the unit

EVAPORATIVE-COOLED CONDENSER

• Evaporative cooling equipment rejects heat by

evaporating a portion of the recirculated water spray and discharging it from the unit with the hot, saturated air. As the spray water evaporates, it leaves behind the mineral content and impurities of the supply water. If these residuals are not purged from the water distribution system, they will become concentrated and lead

to scaling, corrosion, sludge build-up and biological fouling.

• A water treatment monitoring and control

system has been furnished with this unit. Be sure to read the complete manual that has been furnished. All water treatment is a combination of bleed water and chemical treatment for proper control of the residuals and to prevent any biological contamination.

GENERAL INFORMATION

Severe Service:

The following recommended maintenance procedures are basic requirements for normal operating environments. For severe operating conditions, the frequency of inspection and service should be increased. Air containing industrial and chemical fumes, salt, dust, or other airborne contaminates and particulates will be absorbed by the recirculating water system and may form solutions and deposits harmful to the products and personnel.

Safety:

The recirculating water system contains chemical additives for water quality control and biological contaminants removed from the air by the washing action of the water. Personnel exposed to the saturated effluent, drift, or direct contact should use proper precaution. Proper location of the evaporative-cooled condenser requires good judgment to prevent the air discharge from entering fresh air intakes or to avoid allowing contaminated building exhaust from entering the condenser.

EVAPORATIVE-COOLED CONDENSER cont.

Follow local and national codes in locating the evaporative-cooled condenser but as minimum the evaporative-cooled condenser sump must be 15 feet from the nearest intake.

Performance:

Improper location of the evaporative-cooled condenser may seriously degrade the capacity of the equipment. Make sure the equipment is located such that discharge air from the condenser does not enter the condenser air inlet.

Warranties: Please refer to the limitation of warranties in

effect at the time of purchase.

Condenser Tube Inspection:

The coil is leak tested at 450 P.S.I.G. before shipment. AAON will not be responsible for loss of refrigerant. It is the responsibility of the installer to verify that the system is sealed before charging with refrigerant. If the unit is operated during low ambient temperature conditions, freeze protection for the recirculating water system must be provided.

Freeze Protection:

In order to prevent water temperatures from dropping below 50°F, this unit is equipped with a variable frequency drive (VFD) on the fan motors when the refrigeration system is operating.

Recirculating Water System:

Electric sump heaters are available to keep the sump water from freezing when the refrigeration system is not operating. An electric resistance heater is supplied in the vestibule when sump heaters are selected.

Note: The condenser should not be operated with the fan on and the pump cycled on and off to maintain head pressure control under any conditions. The unit is equipped with a water temperature controller which varies fan speed to maintain sump water temperature. This unit is not equipped with a compressor discharge pressure controller for fan speed modulation and therefore can not be operated without water flow.

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