AAON ®
RK SERIES
HEATING • COOLING & COMBINATION ROOFTOP UNITS
INSTALLATION
INSTRUCTION
MANUAL
LISTED
®
▲! WARNING
If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury or loss of life.
FOR YOUR SAFETY
DO NOT STORE OR USE GASOLINE OR OTHER FLAMMABLE VAPORS AND LIQUIDS IN THE VICINITY OF THIS OR ANY OTHER APPLIANCE.
update 7-2000
FOR YOUR SAFETY
WHAT TO DO IF YOU SMELL GAS
•EXTINGUISH ANY OPEN FLAME.
•DO NOT TOUCH ANY ELECTRICAL SWITCH.
•DO NOT TRY TO LIGHT ANY APPLIANCE.
•DO NOT USE ANY PHONE IN YOUR BUILDING.
•IMMEDIATELY CALL YOUR GAS SUPPLIER FROM A NEIGHBOR'S PHONE.
FOLLOW THE GAS SUPPLIER'S INSTRUCTIONS.
•IF YOU CANNOT REACH YOUR GAS SUPPLIER, CALL THE FIRE DEPARTMENT.
1
AAON®
TABLE OF CONTENTS
SECTION |
PAGE NUMBER |
GENERAL DESCRIPTION …………………………………………………………………………… 03
Unpacking
Certification
Codes and Ordinances
OWNER'S INFORMATION …………………………………………………………………………… 04
HEATING / COOLING SYSTEMS …………………………………………………………………… 05
INSTALLATION ………………………………………………………………………………………… 06 Setting the Curb / Unit ………………………………………………………………………… 07 Outside Air Hood ……………………………………………………………………………… 08 Electrical Info
Gas Piping Info ………………………………………………………………………………… 09 Service Clearances
Condensate Piping Info ……………………………………………………………………… 10
GAS UNIT LIGHTING INSTRUCTIONS …………………………………………………………… 11
PERIODIC INSPECTION PROCEDURES ………………………………………………………… 12 Gas Heating, Cooling, Electric, Steam, Hot Water & Chilled Water Units
SERVICE, TROUBLE SHOOTING & MAINTENANCE ………………………………………… 14
Lubrication
Cleaning
FILTER INSTALLATION / REPLACEMENT ……………………………………………………… 15
SERVICING ……………………………………………………………………………………………… 16 Rooftop Unit Replacement Parts …………………………………………………………… 18
SEQUENCE OF OPERATIONS ……………………………………………………………………… 19 Heating
Cooling
Optional Economizer
VAV Systems …………………………………………………………………………………… 20 Power Exhaust Options
COMPRESSOR CHECKOUT PROCEDURE ……………………………………………………… 21
IGNITION CONTROL CHECKOUT PROCEDURE ……………………………………………… 22
FACTORY START-UP FORM ………………………………………………………………………… 23
Owner should pay particular attention to the words: NOTE, CAUTION AND WARNING.
NOTES are intended to clarify or make the installation easier. CAUTIONS are given to prevent equipment damage. WARNINGS are given to alert owner that personal injury and/or equipment damage may result if installation procedure is not handled properly.
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 it's products without notice, obligation or liablity.
© 2000 AAON, Inc., all rights reserved throughout the world.
AAON & AAONAIRE are registered trademarks of AAON, Inc., Tulsa, OK.
P83740 (rev. B • 7-00)
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The units are designed as self-contained heating, cooling or combination units for outdoor installation only, using the refrigerant shown on the rating plate, chilled water, natural or propane gas, electric resistance, steam or hot water.
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.
CERTIFICATION
GENERAL DESCRIPTION
▲! WARNING
Improperinstallation,adjustment,alteration,serviceormaintenancecancausepropertydamage, personal injury or loss of life. Installation and service must be performed by a qualified installer, service agency or the gas supplier.
NOTE: These units must not be used as a "constructionheater"atanytimeduringanyphaseofconstruction. Very low return air temperatures, harmful vapors, and misplacement of the filters will damage the unit and its efficiency.
•GAS HEAT MODELS
(a)Design Certified as a forced air furnace with or without cooling unit.
(b)Certified for outdoor installation only.
(c)Certified for installation on combustible roof with a minimum of 12" high curb.
(d)Certified with Heat Exchanger located downstream from Evaporator coil.
•STEAM OR HOT WATER HEAT MODELS
(a)Certified as a forced air furnace with or without cooling unit.
(b)Certified for outdoor installation only.
(c)Certified for installation on combustible roof with a minimum of 12" high curb.
(d)ARI certified coils.
•ELECTRIC HEAT MODELS
(a)Certified as an electric warm air furnace with or without cooling unit.
(b)Certified for outdoor installation only.
(c)Certified for installation on combustible roof with a minimum of 12" high curb.
•COOLING MODELS
(a)Certified as a commercial central air-conditioner with or without electrically operated compressor.
(b)Certified for outdoor installation only.
(c)Certified for installation on combustible roof with a minimum of 12" high curb.
(d)ARI certified coils.
CODES AND ORDINANCES
System should be sized in accordance with National Warm Air Heating and Air Conditioning Association Literature, or the Guide of American Society of Heating, Refrigeration and Air Conditioning Engineers. The installation must conform with local building codes or, in the absence of local codes with (United States) National Fuel Gas Code "ANSI-Z223.1", (Canada) current CAN /
CGAB149.1 or . 2. Installation Codes for Gas Burning
Appliances and Equipment, current C.S.A. Standard C22.1, Canadian Electrical Code Part 1, and C.S.A. Standard B52 Mechanical Refrigeration Code, and Local Plumbing or Waste Water Codes.
▲! IMPORTANT
The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFC's and HCFC's) as of July 1, 1992. Approved methods of recovery, recycling or reclaiming must be followed. Fines and/or incarceration may be levied for noncompliance.
3
OWNER'S INFORMATION
WARNING
Failure to observe the following instructions will result in premature failure of your system, and possible voiding of the warranty.
DIRECT EXPANSION (DX) COOLING UNITS
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 will accumulate in the compressor. Since the compressor is designed to pump refrigerant gas, damage may occur when power is restored.
If power must be cut off for more than an hour, turn the thermostat system switch to "OFF", and leave it off until the main power switch has been turned on again 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).
During the cooling season, if the air flow is reduced due to dirty air filters or any other reason, the cooling coils will get too cold and will cause excessive liquid to return to the compressor. As the liquid concentration builds up, oil is washed out of the compressor, leaving it starved for lubrication.
THE COMPRESSOR LIFE WILL BE SERIOUSLY SHORTENED BY THIS REDUCED LUBRICATION, AND THE PUMPING OF EXCESSIVE AMOUNTS OF
LIQUID OIL AND REFRIGERANT.
GAS OR ELECTRIC HEATING
The system is designed to cool or heat a given amount of air each minute it operates. If this amount of air is greatly reduced (approximately 1/3 during the heating season), the heat exchanger / heater coil will overheat, and may cut the burner / heater off entirely by action of the safety high temperature limit device which is incorporated in the exchanger or heating area.
GAS HEAT UNITS - Should overheating occur, or the gas supply fail to shut off; shut off the manual gas valve to the furnace before shutting off the electrical supply.
PROLONGED OVERHEATING OF THE HEAT EXCHANGER WILL SHORTEN ITS LIFE.
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.
CAUTION: While the following incorrect operations may not cause damage to the system, they will impair the performance, and may cause the built-in safety devices to cut the system off completely.
1.LOW AMBIENT OPERATION
The cooling section of a direct expansion (DX)
unit will not operate properly when the outdoor temperature is below 55° degrees. Outside air
intake options are recommended if operation below 55° degrees is expected.
2.MULTIPLE UNIT OPERATION
When several units are used in conditioning the space, and part or all of them are combination heating-cooling units, all systems thermostat switches must be set at either heating or cooling (or set at "off"). Do not leave part of the systems switched to the opposite mode. All cooling only units should be switched to "off" at the thermostat during the heating season.
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.
CONDENSATE PIPING
The unit requires a drain trap to be connected to the drainpan at the unit. If codes require a condensate drain line, the line should be the same pipe size as the drain nipple and should pitch downward toward drain.
The condensate drain pipe ("P" trap) is factory supplied and is shipped loose in the control access compartment for field installation. An air break should be used with long runs of condensate lines.
▲! WARNING
Scroll compressors will be damaged by operation with the wrong rotation.
THE LOW PRESSURE SWITCH HAS BEEN
DISCONNECTED AFTER TESTING
AT THE FACTORY.
The wiring must be reconnected and proper rotation determined at the time of start-up by a qualified service technician using suction and discharge pressures gauges.
Any alteration should only be made at the unit power connection.
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HEATING & COOLING SYSTEMS
NORMAL OPERATION
HEATING
Set the thermostat system switch to "HEAT".
Set the thermostat fan switch to "AUTO" or "ON". Set the thermostat temperature at the desired point.
COOLING
Set the thermostat system switch to "COOL".
Set the thermostat fan switch to "AUTO" or "ON". Set the thermostat temperature at the desired point.
AIR CIRCULATION
Set the thermostat system switch to "OFF". Set the thermostat fan switch to "ON".
Do not change temperature setting.
With these settings, the air circulating blower will run continuously but the air will not be heated or cooled.
SYSTEM OFF
Set the thermostat system switch to "OFF". Set the thermostat fan switch to "AUTO". Do not change temperature setting.
With these settings, the system is shut down, with the exception of the control system power (24 volts), and the crankcase heater of the compressor (about 60 watts).
DO NOT TURN OFF THE MAIN POWER SWITCH.
NIGHT AND VACANT WEEKEND OPERATION
If it is desired to reduce the operating time during the night, and during periods when the space is unused, it is recommended that the temperature setting be raised about five degrees during these periods of the cooling season, and lowered about ten degrees during the heating season.
GAS HEATING SYSTEM
The heating section is for use with natural gas supply pressure of 6" to 10.5" Water Column. The unit can also be fired on propane gas with a supply pressure to the valve of 11" to 12" Water Column. A 1/8" pressure tap must be supplied by the installer in the piping just ahead of the gas valve. The rating plate on the furnace shall be inspected to make sure that the unit is stamped for the proper gas. The pressure tap on the outlet end of the gas valve should be removed and the valve adjusted for the proper manifold pressure to 3.5" on natural gas and 10.5" for propane gas.
The burner area is not sealed and combustion air is supplied by a centrifugal blower which draws in fresh air through a protected opening. This air is introduced into the burner tubes by the action of the induced draft blower. This insures an even flow of primary and secondary air to the burners.
The heating system and safety controls are 100% tested on each unit before it leaves the factory.
INSTALLATION IS TO BE ADJUSTED TO OBTAIN AN AIR TEMPERATURE RISE WITHIN THE RANGE SPECIFIED ON THE RATING PLATE.
The units are equipped with a direct spark ignition system which proves the burner operation during each call for heat.
Power to the ignition control is 24 volts to reduce hazards. Burner ignition is by a high intensity spark. When heat is called for, the cooling system is inoperable except for the indoor blower motor. Actual heating is accomplished by firing gas into the heat exchanger assembly.
ELECTRIC HEATING SYSTEM
Heating is accomplished by passing electrical current through a specified amount of resistance heaters which will produce the required heat. The indoor blower motor will energize at the same time as the heaters.
STEAM OR HOT WATER HEATING SYSTEM Heating is accomplished by passing steam or hot water through the steam or hot water coil assembly.
COOLING SECTION • DX
All direct expansion refrigeration systems are factory assembled, charged with refrigerant, tested and operated. On all units 8 ton and larger the refrigerant system includes multiple circuit evaporator and condenser coils providing two or more stages of cooling. These systems are provided with liquid line filter driers, expansion valves and fully hermetic compressors. Compressors are equipped with a positive pressure forced lubrication system. The air cooled condenser coil(s) is constructed of copper tubes with aluminum fins, the air is pulled through with propeller fans. The evaporator coil is draw through, made of copper tubes with aluminum fins.
The refrigeration section of these appliances has been found acceptable with applicable provisions of "ANSI / UL 1995" and current "C.S.A. Standard C22.2" by E.T.L.
NOTE: Crankcase Heater Operation
Some units are equipped with a compressor crankcase heater, which should be energized at least 24 hours prior to setting the thermostat for cooling operation.
COOLING SECTION • CHILLED WATER or NON-COMPRESSORIZED UNIT
Chilled water or non-compressorized units have factory installed coils. These systems are provided with internal header connections for field connection. Coils are aluminum fin / copper tube construction.
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INSTALLATION
▲! CAUTION
If outside air is in contact with the bottom of the unit, the unit must have the bottom insulation option or be field insulated.
DO NOT DRILL OR PUNCH HOLES IN BASE OF UNIT FROM INSIDE THE UNIT OR FROM BELOW TO ATTACH DUCTWORK. LEAKING MAY OCCUR IF UNIT BASE IS PUNCTURED.
SEE DETAIL "A"
SECTIONAL VIEW OF UNIT ON ROOF CURB
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▲! WARNING
INSULATION MATERIALS MAY
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6
AAON Rooftop units are designed for fast, easy installation. The curb is mounted first and must be located so that duct connections will be clear of structural members of the building.
SETTING THE CURB
When using the factory curb, make openings in roof decking large enough to allow for duct penetrations and workspace only. Do not make openings larger than necessary. Set the curb to coincide with the openings. Make sure the curb is level.
SETTING THE UNIT
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 / coils or condenser fans.
It is recommended lifting the unit with the outside air hood in the downward shipping position, however the unit may be lifted with the outside air hood in the open position.
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.
99" minimum length
LIFTING DETAIL TYPICAL FOR 2 - 25 TON UNITS
INSTALLATION continued
Hoist unit to a point directly above the curb and duct openings. Lower unit while guiding the unit to align with utility opening and duct openings. Be sure that the gasket material has been applied to curb. Continue lowering the unit until the unit skirt fits around the curb. Make sure the unit is properly seated on the curb and is level.
180" minimum length
LIFTING DETAIL TYPICAL FOR 26 - 60 TON UNITS
The unit shall be installed so that the rectangular flue (if applicable) is located at least 120" away from any opening through which combustion products could enter the building. The unit shall also be installed so that the flow of combustion and ventilating air is not obstructed from reaching the furnace. Do not position flue opening to discharge into a fresh air intake of any other piece of equipment.
▲! WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a qualified installer, service agency or the gas supplier.
Install the gas fired unit to assure the flow of combustion and ventilating air is not obstructed from reaching the heater and that the flue outlet is located at least 120 inches away from any opening through which combustion products could enter the building.
▲! CAUTION
Where the supply or warm air duct passes through a combustible roof, a clearance of one inch must be maintained between the outside edges of the duct and combustible material in accordance with National Fire Protection Association Standard No. 90A. Provide flashings or enclosure between structure and roof and all joints must be sealed with mastic roofing to ensure a watertight seal.
All roofing work should be performed by competent roofing contractors to avoid any possible leakage.
7
INSTALLATION continued
OUTSIDE AIR HOOD
For proper unit operation, the air hood must be opened at start-up as shown below:
AIR HOOD SHOWN IN THE SHIPPING POSITION
(CLOSED)
Remove shipping screws from each side of the hood in the "closed" postion. Lift hood to the "open" position, seal flange and secure with sheet metal screws.
Air hoods may vary according to unit size and options. The illustration shown is for practical guidelines for all outside air hoods.
Outdoor air intake adjustments should be made according building ventilation or local code requirements.
AIR HOOD SHOWN IN THE OPEN POSITION
▲! WARNING
Electric shock hazard. Can cause injury or death. Before attempting to perform any service or maintenance, turn the electrical power to unit to OFF at disconnect switch(es). Unit may have multiple power supplies.
ELECTRICAL
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 should not be run inside the same conduit. The unit must be electrically grounded in accordance with the current National Electric Code, ANSI / NFPA No. 70. In Canada use current C.S.A. Standard C22.1 Canadian Electric Code Part 1.
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.
AIRFLOW IS TO BE ADJUSTED AFTER INSTALLATION TO OBTAIN AN AIR TEMPERATURE RISE WITHIN THE RANGE SPECIFIED ON THE RATING PLATE.
DUE TO JOB SPECIFICATION REVISIONS, IT MAY BE NECESSARY TO ADJUST OR CHANGE THE SHEAVE OR PULLEY TO OBTAIN THE DESIRED AIRFLOW AT THE TIME OF INSTALLATION.
START-UP TECHNICIAN MUST CHECK BLOWER MOTOR AMPERAGE TO ENSURE THAT THE AMPERAGE LISTED ON THE MOTOR NAMEPLATE IS NOT EXCEEDED.
NOTE: All units are factory wired for 208 / 230, 460 or 575 volt. If unit is to be connected to a 208v supply, the transformer must be rewired for 208v service. For 208v service interchange the yellow and red conductor on the low voltage control transformer.
RED - BLK 208 volt ; YEL - BLK 230 volt.
▲! CAUTION
On three phase units the rototation must be checked on ALL MOTORS AND COMPRESSORS.
SCROLL COMPRESSORS ARE DIRECTIONAL.
Rotation must be checked on start-up by a qualified service technician using
suction and discharge gauges.
Scroll compressors will FAIL if run in the wrong direction. Blower and condenser rotation should be checked and only be altered if necessary at the power connection.
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