GENERAL DESCRIPTION 1. GENERAL DESCRIPTION Generally speaking conventional air conditioners cool the entire enclosed environment. They act as “heat exchangers”, requiring an interior and an exterior unit (condenser) to exhaust exchanged heat to the outdoors. Unlike conventional air conditioners, the SPOT COOL is a cooling system which directs cool air to particular areas or objects. SPOT COOL has the following features; Fig.
CONSTRUCTION, SPECIFICATIONS and DATA 2. CONSTRUCTION AND SPECIFICATION 2-1. Construction Fig.
CONSTRUCTION, SPECIFICATIONS and DATA 1) Basic Construction The SPOT COOL is compact in construction because the condenser and the evaporator are enclosed in one unit. The interior is divided into two sections. The front face is equipped with the evaporator and control box. The rear section contains the condenser and the compressor. 2) Air Flow (See Fig. 1-2) 1.
CONSTRUCTION, SPECIFICATIONS and DATA 2-2 Specifications Item Model 30HU [Rating Condition] DB 35˚C 95˚F [Features] Power frequency ..................................................... (Hz) Line Voltage .......................................................... (Volt) Power consumption ............................................... (Kw) Current consumption .......................................... (Amp) Power factor ........................................................... (%) Starting current .
REFRIGERANT SYSTEM 3. REFRIGERANT SYSTEM The component parts of the refrigerant system include the followings; • Compressor • Evaporator • Condenser • Modulating tank • Capiliary tub • High pressure switch These parts are all connected by copper piping. All the connections have been brazed. Fig.
REFRIGERANT SYSTEM 3-1. Compressor The compressor used for this unit is a reciprocating type. It is a hermetic compressor which incorporates a drive motor and a compression mechanism in an enclosed vessel. 3-1-1. Construction The reciprocating type compressor consists of a drive section (motor) and a compressin mechanism as shown in Fig. 3-2. When the rotor shaft of motor rotates, the crank shaft causes the piston to reciprocate in the cylinder and absorb and compress the refrigerant.
REFRIGERANT SYSTEM 3-1-2. Operation 1) Suction When the piston is pushed down, pressure inside the cylinder lowers. When this pressure becomes less than the suction side (low pressure side) pressure, the suction valve at the top of the cylinder is pushed open by the suction side pressure and the refrigerant is sucked into the cylinder. See Fig. 3-3. Fig. 3-3 Suction 2) Compression The refrigerant in the cylinder is pushed up by the piston. As its capacity reduces, its pressure increases gradually. See Fig.
REFRIGERANT SYSTEM 3-2. Condenser The condenser, which serves as a heat exchanger, has thin aluminum projections called spine fins fastened toa copper tube. Heat is exchanged by forcing cooler air across the condenser fins. 3-3. Capillary Tube The following table shows the specifications of the capillary tube. Model Qty Purpose of Use I.D, (mm) Length (mm) 30HU FOR COOLING Ø1.4±0.02 445 4 3-4. Evaporator The evaporator is a heat exchanger using plate-fins and tubes.
REFRIGERANT SYSTEM 3-5. Modulating Tank The modulating tank consists of a copper pipe and tank sections, each being separated from the other. The pipe connects to the evaporator outlet at one end and to the suction pipe of the compressor at the other; the tank connects to the evaporator inlet. The modulating tank is covered with a heat insulator that eliminates thermal effects from ambient temperature.
REFRIGERANT SYSTEM 3-7. Piping The parts of the cooling system are connected by copper pipe. In the unit, the refrigerant cycle is enclosed. Each connection has been brazed. the circled portion in the figure shows the parts which have been brazed. Fig.
ELECTRICAL SYSTEM 4. ELECTRICAL SYSTEM The component parts of the electrical system include the following: • Control box • Overcurrent relays • Control switch • Relays • Fan motor • Lamps etc. • Compressor motor Fig.
ELECTRICAL SYSTEM 4-1. Control Box The interior of the control box is shown in the figure below. Fig. 4-2 Main Control Box Fig.
ELECTRICAL SYSTEM 4-1-1. Auxiliary Relay When the power is supplied to the unit, this relay is energized across terminals 7 and 8 closed across terminals 5 and 3 and across 6 and 4. These states remain unchanged in all operation modes (FAN or COOL). If one of the errors mentioned below has occurred at the unit, the auxiliary relay is deenergized across terminals 7 and 8, and opened across terminals 5 and 3 and across 6 and 4.
ELECTRICAL SYSTEM 4-1-2. Fan Motor Relay This fan motor relay is closed when the unit is in operation of FAN and COOL mode, and supply power to the fan motor of the evaporator. In the following case, the relay opens to cut off power to the fan motor. When the auxiliary relay is opened by the overcurrent relay OFF, compressor overlaod relay OFF or high pressure switch OFF. Specifications Rated Voltage: AC230 Volts Rated current: 15 amps Fig. 4-6 Circuit of Fan Motor Relay Fig.
ELECTRICAL SYSTEM Fig. 4-9 Compressor Relay 4-1-4. Overcurrent Relay For three-phase blower motor and compressor motor, an overcurrent relay is usually used as a safety device. The overcurrent relay prevents motor coil from burning if overcurent has flown into the motor due to abnormal load applied to the blower motor or compressor motor, extraordinary change in supply voltage, or loss of current in one phase.
ELECTRICAL SYSTEM 4-2. Control Switch The control switch is employed to start or stop operation. This switch is of 250V, 20A rating rotary type (3-position). The switching positions are OFF-FAN-COOL. Each contact is switched by the cam uniting with the shaft. When the unit is hung from the ceiling, pulling the pull cord allows operation of the control switch. Switch Terminals OFF FAN (5) - (2) Conduct OFF OFF (5) - (1) OFF Conduct (5) - (4) OFF OFF COOL Conduct Conduct Fig.
ELECTRICAL SYSTEM 4-3. Fan Motor The fan motors are of three phase, induction type. The following table shows the specifications of the fan motors. When the control switch is set to FAN, the evaporator fan motor rotates. When it is set to COOL, both the evaporator and condenser fan motors rotate. Model/Spec. Output (Watt) Fig. 4-14 Rated Voltage (Volt) For Evaporator 220 750 For Condenser 220 400 Rated Fan Motor 4-4. Compressor Motor The compressor motor is a three phase motor.
ELECTRICAL SYSTEM 4-5. Thermostat When the evaporator has freezed, the contacts of thermostat open to stop the compressor and the ventilating operation is automatically initiated. When the evaporator is unfreezed, the contacts close to restart the compressor and the cooling operation is initiated. The heat sensing tube of thermostat is mounted at the evaporator outlet tube and is insulated from surrounding air by het insulating material. The setting of thermosate is fixed at -1.
ELECTRICAL SYSTEM 4-6. Wiring Power supplied cord is applied with 12AWG (4-core) wires. Proper connections are indicated at all the wire ends. Faston type No. 250 or 187 terminals are used. Fig.
ELECTRICAL SYSTEM 5. DATA 5-1. Exterior Dimensions Diagram Fig.
ELECTRICAL SYSTEM 5-2. Construction diagram Fig.
ELECTRICAL SYSTEM 5-3. Cooling Capability Characteristics 1) Cooling Capability curve Fig. 5-3 Cool Capability Curve 2) Current consumption curve Fig.
ELECTRICAL SYSTEM 3) Cool air temperature difference curve Fig. 5-5 Cool Air Temperature Difference Curve 4) Static pressure and air volum curve of cool air Fig.
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Repair 1. TROUBLESHOOTING .............................................................................. 24 2. INSPECTION OF UNIT ............................................................................ 26 3. DISASSEMBLY ....................................................................................... 27 4. INSPECTION AND REPAIR OF ELECTRICAL SYSTEM .............................. 34 5. INSPECTION AND REPAIR OF REFRIGERANT SYSTEM ........................... 38 6. REASSEMBLY ........................
1. TROUBLESHOOTING Before troubleshooting this system the following inspection should be performed. a) Inspection of power source voltage and phase sequence Check the voltage of the power source. Model 30Hu: Three phase, 220 volt ± 15%, 6-Hz. Check the operation and condition of the fuse or circuit breaker in the power source. Check the rotating direction of blower. If the blower rotates in the opposite direction, phase sequence of the power source is reverse.
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2. INSPECTION OF UNIT In case of trouble, perform the following inspection before disassembly. 2-1. Inspection of Clogging at Heat Exchanger of Evaporator and Condenser. Check the heat exchanger of the evaporator and condenser for dier and clogging. If they are dirty or clogged, remove and wash each part. Fig. 2-1 Spine Fins of the Condenser Fig. 2-2 Operating Environment Fig. 2-3 Inspection of Cooling Capacity 2-2. Examination of Operating Environment Check the environment around the unit.
3. DISASSEMBLY [MODEL 30HU] Fig.
3-1. Removal of outer panels 1) Removal of following parts 1. Air filters 2. Exhaust duct 3. Front panel 4. Evaporator panel 5. Condenser panel 6. Right side panel 7. Rear panel Fig. 3-2 Removal of Parts Fig. 3-3 Removal of Control Box Cover Fig. 3-4 Removal of Power Wire 2) Remove three screws from the control box and open the control box cover. 3) Remove four screws from the sub-control box and opent the sub-control box cover. 4) Remove four lead wires of the power wire from the terminal block.
3-2. Removal of Electrical Parts 1) Remove the electrical wiring according to the wiring diagram as shown below. Fig.
2) Remove the electrical partsk in the control box and sub-control box. Fig. 3-6 Removal of Electrical Parts 3) Remove the control switch, power indicated lamp and warning lamp as shown. Fig.
3-3. Fig.
1) Remove five wing nuts and remove the fan casing. Fig. 3-9 Removal of Blower Housing Fig. 3-10 Removal of Sirocco Fan Fig. 3-11 Removal of Blower Motor 2) Remove the set bolt using a box wrench and their remove the sirocco fan. NOTE: Tightening torque for set bolt. 170~190kg-cm (12.5~13.7 ft-lb) 3) Remove four nuts and remove the blower motor.
3-4. Removal of blower assembly (for condenser) Fig. 2-1 Construction of Hermetric Rotary Type Compressor 1) Remove the nut (left handed screw) and fan. NOTE: Tightening torque for nut. 450±50kg-cm (33±3.7 ft-lb) Fig. 3-13 Removal of Fan Fig. 3-14 Removal of Blower Motor 2) Remove four nuts and remove the blower motor from bracket.
4. INSPECTION AND REPAIR OF ELECTRICAL SYSTEM 4-1. Inspection of Control Switch At each position of the control switch, there should be continuity across the following terminals.. Switch Position Conducting Terminals OFF 2-5 FAN 1-5 Fig. 4-1 Inspection of Control Switch Fig. 4-2 Inspection of Lamps Fig. 4-3 Inspection of Condenser Fan Motor Fig. 4-4 Inspection of Evaporator Fan Motor COOL 1 - 5, 4 - 5 If there is no switch continuity, replace the control switch. 4-2.
4-4. Inspection of Thermostat Check for coninuity across two terminals of the termostat. At normal temperature, (17˚C or higher) there is continuity across two terminals.. If continuity is interrupted across the terminals, replace the thermostat. 4-5. Inspection of High Pressure Switch Check for continuity across two terminals of the high pressure switch. At normal pressure when the unit is stopped, there is continuity across two terminals.
4-8. Inspection of Compressor Relay Check for continuity across the terminals when the test button is depressed and/or released. Depressed: All couples of terminals are conducted. Released: All couples of terminals are not conducted. Measure the resistance across terminals A and B. Standard resistance: 650 ~ 800Ω When the resistance is out of this range, replace the compressor relay. Fig. 4-8 Inspection of Compressor Relay Fig. 4-9 Inspection of Over Current Relays 4-9.
4-10. Inpsection of Fan Motor Relay. Check for continuity across the terminals when the test button is depressed and when it is released. Depressed: All couples off terminals are conducted Released: All couples of terminals are not conducted. (Couples of terminals: 11 - 12, 13 - 14, 15 - 16 and 19 - 20.) Measure the resistance across termianls A and B. Standard resistance: Fig. 4-10 Inspection of Fan Motor Relay 1900~2100Ω.
5. INSPECTION AND REPAIR OF REFRIGERANT SYSTEM 5-1. Inspection When something is wrong with the refrigerant system, it fails to cool sufficiently. the possible cause of this failure is clogging, leakage or insufficient refrigerant. In such a case, inspect the system according to the following procedure. 5-1-1. Inspection of Refrigerant Clogging Check the component parts of the refrigerant system and the pipes connecting them for clogging.
The gas leak tester should be used in the following way. 1) Check the amount of propane liquid in the container. 2) Install the propane container to the gas leak tester body by turning it fully clockwise. 3) When lighting the tester, insert the match into the ignigting hole of the tester and turn the adjusting handle slowly counterclockwise. This will ignite the gas leak tester. 4) The reactor (copper ring) must be red heat, but the flame must be kept as small as possible.
(1) Proper Fitting, Proper Clearance In general, the strength of brazing filler metal is lower than that of the base metal. So, the shape and clearance of the brazed fitting are quite important. As for the shape of the brazed fitting, it is necessary to maximize its adhesive area. The clearance of the brazed fitting must be minimized to pour brazing filler metal into it by use of capillary attraction. Fig.
5-2-2. Removal of Refrigerant Cycle Relatives CAUTION: 1. When removing the brazed portion, protect the other parts with a steel plate, asbestos, etc. to keep the other parts from the flame. 2. Before removing the refrigerant cycle from the brazed portion, be sure to cut off the end of pinch-off tube and bleed the cycle of gas. 3. In this case, also bleed the refrigerant cycle of N2 gas through the open pinch-off tube in order to prevent oxidization. Fig.
5-3. Charging the System with R-22 Be sure to purge the system and charge the system with refrigerant to the specified amount in the following. CAUTION: 1) When handling refrigerant (R-22), the following precautions should be observed. A) Always wear eye protection while handling refrigerant. B) Keep the refrigerant container blow 40˚C (104˚F). C) Do nnot handle refrigerant in an enclosed room. D) Do not handle refrigerant near an open flame (especially never while smoking a cigarette).
(3) Connect the charging hoses (red one on high pressure side, and blue one on low pressure side) of the gauge manifold to the process tube fittings. NOTE: Connect the hoses using care not to mistake the high pressure side for the low pressure side and vice versa. (4) Connect the charging hose (green) at the center of the gauge manifold to the vacuum pump. Fig. 5-7 Connection of Gauge Manifold 5-3-2. Purging (1) Open the high pressure valve (HI) and the low pressure valve (LO) of the gauge manifold.
5-3-4. Checking Gas Leak (1) Remove the charging hose (green) from the vacuum pump, and connect the hose to the refrigerant cylinder (R22). NOTE: Before this stip, fit the mouthpiece for refrigerant cylinder (service tool: No. 945502050) to the outlet of the refrigerant cylinder. Fig. 5-10 Purging Air inside Charging Hose Fig. 5-11 Charging with Refrigerant for Gas Leak Check (2) Loosen the nut on the gauge manifold sid e fo the charging hose (green).
5-3-5. Purging (Repeat) (1) Close the valve of the refrigerant cylinder. Then remove the charging hose (green) from the refrigerant cylinder, and connect it to the vacuum pump. NOTE: Keep the high pressure valve and the low pressure valve of the gauge manifold closed. (2) In the procedure of above “5-3-2.), purge the system until the low pressure gauge indicates 750mmHg or larger. (For 15 minutes or more.
(3) Place the refrigerant cylinder on a scale. (weighting capacity: 70lbs; graduated in 0.2 oz.) (4) Open the high pressure valve of the gauge manifold and the valve of the refrigerant cylinder. Charge the system with refrigerant to the specified amount, looking at the graduations of the scale. [Specified Charging Amount of Refrigerant] Fig. 5-14 If the system cannot be charged with specified amount of refrigerant under this condition, follow the steps below: 1. Close the high-pressure valve of manifold.
5-4-2. Removal of Gauge Manifold (1) Pinch off the pinch-off tube with a pinch-off tool. (2) Remove the gauge manifold and the process tube fitting. Crush the end of the pinch-off tube. (3) Braze the end of the pinch-off tube. (4) Make sure that gas leak is not observed at the pinched off portion and the brazed end. 6. REASSEMBLY Reassemble the unit in the reverse order of removal. Fig. 5-15 Described below are the parts that need special care in reassembling the unit.
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