maintenance vrv

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aircraft maintenance hangar

OPERATION & MAINTENANCE MANUAL HVAC SYSTEM (AIR SIDE)

VRV AIRCONDITIONING SYSTEM

6. MAINTENANCE IMPORTANT: The material contained in this Section is designed as a general overview of maintenance requirements and may not contain answers for specific maintenance questions. Consult the manufacturers’ instruction manuals, in BOOK-4 section 13 of this O&M for specific maintenance information. 6.1 GENERAL 6.1.1 Maintenance Precautions Personal Protective Equipment (PPE) Required! Installing/servicing this unit could result in exposure to electrical, mechanical and chemical hazards. Before installing/servicing this unit, technicians MUST put on all Personal Protective Equipment (PPE) recommended for the work being undertaken. ALWAYS refer to appropriate MSDS and OSHA guidelines for proper PPE. When working with or around hazardous chemicals, ALWAYS refer to appropriate MSDS and OSHA guidelines for information on allowable personal exposure levels, proper respiratory protection and handling recommendations. If there is a risk of arc or flash, technicians MUST put on all Personal Protective Equipment (PPE) in accordance with NFPA70E or other country-specific requirements for arc/flash protection PRIOR to servicing the unit. Failure to follow recommendations could result in death or serious injury.

WARNING Hazardous Voltage! Disconnect all electric power, including remote disconnects before servicing. Follow proper lockout/tagout procedures to ensure the power can not be inadvertently energized. Failure to disconnect power before servicing could result in death or serious injury. WARNING Contains Refrigerant! AVOID prolonged breathing of the vapor. Prolonged inhalation of refrigerant is extremely dangerous; death can occur without warning

CAUTION

ALWAYS wear protective goggles when working with refrigerant. If liquid refrigerant gets in your eye, permanent blindness may result DO NOT allow refrigerant to come in contact with your skin. Refrigerant has a very low boiling point, which will cause frostbite

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6.1.2 Maintenance Planning Since maintenance work is generally done in the least time possible, maintenance activities should be planned. In addition to ensuring that the necessary materials, tools, parts are assembled and prepared for use in advance of the work, the maintenance activity plan should also cover all aspects of the activity which may include the following. Scheduling with operations

1. Site access 2. Calibrated test equipment for each test required 3. Necessary lighting, electrical power, and service air to perform the work 4. Cleaning aids consisting of clean, white, lint-free cloths; solvents; vacuum cleaner;

and dry compressed air 5. Personnel safety equipment required for the specific maintenance activities being

performed

6.1.3 Maintenance program

A total maintenance program for Hangar facility must contain elements of both preventive and predictive maintenance. Preventive maintenance is the systematic care and servicing of equipment and facilities to prolong their useful life. Predictive maintenance consists of the performance of periodic equipment inspections to identify and monitor symptoms (such as increasing wear, abnormal vibrations, or increasing power usage) which indicate that mechanical failure of a piece of equipment may be approaching. The goal of predictive maintenance is to develop an awareness of developing problems so that needed repairs can be made on a planned rather than on an emergency basis and unscheduled system down time resulting from unpredicted equipment failure is avoided. Effective execution of a total site maintenance program requires the implementation of the following elements.

1. Training and instruction of maintenance personnel, operators, and users of the particular equipment systems in proper operation, maintenance, and safety procedures.

2. Systematic, periodic inspection and servicing of plant systems and equipment by skilled maintenance personnel.

3. Assignment of specific maintenance responsibilities to skilled maintenance personnel and to operators of equipment.

4. Continuing supervision of the site maintenance program. 5. Periodic utility systems maintenance inspections to ensure the maintenance program

is being implemented.

Only a regular and organized scheme of maintenance work, planed, to cover all details of the installation within given maintenance periods, can ensure continued satisfactory operation with a minimum liability to interruption to supply due to equipment faults. A planned maintenance scheme should include a system of logging, wherein records are kept on inspection, maintenance and repair of all items of plant and equipment.

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Careful attention must be given to securing the safety of personnel and equipment while maintenance or repair is in progress. A code of safety rules based on system “permit to work” is recommended. Where maintenance work in progress is in progress, a DANGER notice must always be attached to any ‘Live” apparatus calling attention to the danger of approach, A CAUTION notice must always be attached to plant or its associated control equipment which may occasioned by interference. Before any work is commenced on any items of equipment, the supply and ancillary circuits must be isolated and locked off if possible. Warnings! In the event of a refrigerant leak, thoroughly ventilate the room. If refrigerant leaks and

comes in contact with an open flame, toxic gases will be generated. After installation & maintenance work has been completed, check for refrigerant leaks. Caution: Do not touch the refrigerant pipes with bare hands during operation. The refrigerant

pipes are hot or cold depending on the condition of the flowing refrigerant. If you touch the pipes, burns or frostbite may result.

After stopping operation, be sure to wait at least five minutes before turning off the main power switch. Otherwise, water leakage or breakdown may result.

Do not use refrigerant other than R410A refrigerant. If another refrigerant is used, the chlorine will cause the oil to deteriorate.

Use the following tools specifically designed for use with R410A refrigerant.

Gauge manifold Flare tool Charge hose Size adjustment gauge Gas leak detector Vacuum pump adapter Torque wrench Electronic refrigerant charging scale

Be sure to use the correct tools. If dust, debris, or moisture enters the refrigerant lines, refrigeration oil deterioration may result.

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6.2 GENERAL MAINTENANCE

Inspection Action Frequency

Hangars and Support

Inspect hangers and supports: Check for corrosion, wear, and failed parts. Make certain that all supports are in line with

the piping and tracking true, Make certain that each hanger is carrying its

share of the load; and that there are no signs of imminent failure of any stressed member.

Yearly

Check the refrigerant piping for leaks and proper support. Repair defective connections. 3 monthly

Check piping insulation to make sure the insulation is still wrapped around piping. Repair or replace if needed.

3 monthly

Check piping for dents and frosting. Replace piping section if dents are found. 3 monthly

Refrigerant Piping

Check piping for unnecessary vibration, noise, and wear. Repair and eliminate vibration and wear. 3 monthly

Inspect outer surface for damage. Repair or replace as necessary Yearly

Insulation Check integrity of vapors seals Yearly

Indoor Unit

Remove and clean air filter Monthly

Clean surfaces of casing 3 monthly

Brush or vacuum clean evaporator coil surfaces 3 monthly

Check for correct operation of control 3 monthly

Check fan is free to rotate 3 monthly

Check for unusual noise of vibration 3 monthly

Clean out drip tray and ensure condensate drain is free from obstruction 3 monthly

Check unit for sign of leakage 3 monthly

Indoor Unit General Inspection

Check and maintain component items – refer to individual components maintenance schedule Various

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General Maintenance Continued…


Outdoor Unit

Inspect units for signs of leakage or corrosion Clean of any deposits and treat any bare metal accordingly

3 monthly

Clean condenser coil surfaces 3 monthly

Check fans are free to rotate and impellers are secure onto shaft 3 monthly

Check operation of control 3 monthly

Check refrigerant charge 3 monthly

Check operation of crank case heater 3 monthly

Check crankcase oil level, top up as required 3 monthly

Check for unusual noise or vibration 3 monthly

Outdoor Unit General Inspection

Check and maintain component items – refer to individual components maintenance schedule Various

6.3 COMPRESSOR


Check compressor for sign of leakage Weekly

Check oil level Weekly

Check oil is contaminated with refrigerant Weekly

Check for unusual noise or vibration Weekly

Inspect compressor for sign of corrosion Yearly

Check security of electrical connection Yearly

Compressor

Check and maintain component item (Electric Motor) – refer to individual component maintenance schedule.

Various

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6.4 FILTER Caution: Do not dry the filters in direct sunlight or by using a heat source, such as an electric

heater: this may warp them. Do not wash the filters in hot water (above 50°C), as this may warp them. Make sure that the air filters are always installed. Operating the unit without air filters

can cause malfunction.

Caution: In removing the filter, precautions must be taken to protect eyes from dust. When the filter is removed, do not touch the metallic parts inside the indoor unit,

otherwise injury may result.


Take the manometer reading, If the reading shows the filter cells are at their maximum pressure drops, they should be washed. After washing check the condition of filter medium, if damaged replace.

Monthly Filter

Wipe any accumulated dirt from the retaining channels and frames Monthly

Note : On replacing access doors check that the integral seals give a good air seal, if not, replace seals

Please refer to manufacturer literature on sections 13.4, 13.5, 13.6, 13.7 of this manual for filter removal & cleaning proof particular models

6.5 COOLING COIL


Check pipe work connection for leak 3 Monthly

Check coil matrix is clean, unobstructed and air flow is evenly distributed over coils 3 Monthly

Check condensate drain pans and connection are clear. Check drain pipe is properly attached 3 Monthly Cooling Coil

Clean Coil Matrix, Use soft brush and mild detergent solution, If heavily contaminated with grease use steam lance, Take care not to damage or distort fins

6 monthly

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6.6 FAN


Check fan is running smoothly without excessive noise or vibration Daily

Check flexible connection are secure and airtight Weekly

Check that fan guards is clean and unobstructed Weekly

Check anti-vibration mountings / hangars are secure, free to move and in good condition Monthly

Check impeller and shaft for freedom of movement and balance 6 monthly

Clean and check casing internally and externally, repair any corrosion or damage to finish found. Check all bolted joints are secure

Yearly

Fan

Check and maintain component items (electric motor) – refer to individual component’s maintenance schedule

Various

6.7 ELECTRIC MOTOR Important: Always ensure that electrical supply to the motor is positively isolated before carrying out any operation


Generally check motor to ensure casing ventilation louvers are unobstructed, alignment is correct, holding down bolts and pulley/couplings are secure, and motor without excessive vibration, temperature and noise.

Monthly

Totally enclosed motors only-Check that casing drain holes are unobstructed or if plugged, remove plugs to drain off any accumulated condensation.

Monthly

Check motor terminals are secure, cables show no signs of overheating, terminal box is internally dry and clean, and cover is refitted securely

6 monthly

Check that insulation resistance across winding is at an acceptable value 6 monthly

Check centrifugal switch for wear and action 6 monthly Check drawn full load current does not exceed value stated on the name plate 6 monthly

Electric Motor

Dismantle and overhaul motor in accordance with manufacturer recommendations 3 yearly

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