Air Conditioning Planned Maintenance Produced by Joe Marchese

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Air ConditioningPlanned MaintenanceProduced
byJoe Marchese
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Why Perform Planned Maintenance?

• To keep the equipment performing in good
  condition and at peak efficiencies
• They help to maintain good indoor air quality
• They help protect our environment

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How do PMs keep equipment at peak efficiencies?

• Clean coils keep the heat transfer rate and
  temperature difference between the refrigeration
  and the cooling medium at optimum levels.
• Running system with an undercharge of refrigerant
  will cause the system to run longer not to its
  design efficiencies.

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How Do PMs Keep Equipment at Peak Efficiencies?

• Poor electrical connects can cause the system to
  work harder
• Improper gas combustion will decrease the
  efficiency of a gas appliance may cause CO to
  be produced
• Dirty filters will reduce the airflow through a
  system which will decrease the systems
  efficiencies

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Poor Indoor Air Quality

• Can lead to Lung/Respiratory illnesses
• Can inflame allergies
• Can cause damage to interior furnishings
• Stagnant water left in an appliance can be a
  breeding ground to biological contaminants.
• Such as Legionnaire's Disease

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Protects Our Environment

• PM inspections will reduce the amount of
  refrigerant released in to our atmosphere.
• This will reduce
• Ozone depletion
• Global warming

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PM Inspections Will Also

• Help to even out the workload of a contracting
  company
• Allow time for scheduled repairs - reduces the
  amount of emergency calls

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What is the most important concern for a service
technician while performing a preventative
maintenance inspection?

• SAFETY

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Safety

• Good safety practices helps to avoid injuring
  yourself prevents damage to the equipment.
• Must be first on your mind at all times
• Always remove any loose items you may be wearing
  when working around equipment with moving or
  rotating parts

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Safety

• Always lift with your legs and not with your back
• Wear a back support belt when a lifting heavy
  objects
• When working with electrical equipment always
  verify the power is off
• Do not rely on a shut off switch or disconnect
  being off - Always check yourself

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Other Safety Concerns

• Rotating moving part
• Sharp objects
• Hot and Cold surfaces and work areas
• Injury form working with refrigerants
• Refrigerant cylinders

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Other Safety Concerns

• Gas leaks
• Oil leaks
• Incomplete combustion - CO poisoning
• Ladders
• Confines spaces

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Personal Protective (Safety) Equipment (PPE)
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Safety Shoes
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Safety Goggles
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Ear Plugs
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Gloves
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Who performs PM inspection?

• Normally it is those technicians starting out in
  the industry
• Occasionally an experience technician will
  perform the inspections

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When are PMs normally performed?

• Depending on the type of equipment they can be
  performed
• Monthly
• Quarterly
• Semi-Annually
• Annually

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How long should a PM inspection take?

• Mainly depends on
• the type of equipment
• the detail in which the inspection is performed

SHORT INSPECTION vs. LONG INSPECTION
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How Much Should a PM Cost a Customer?

• The price of a P/M inspection is based on
• Travel setup time
• How long it will take to complete
• How maintenance supplies are used

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What Is The Most Important Tools Used On A PM
Inspection?

• Your hands
• Your eyes
• Your ears
• Your nose

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What Maintenance Items Should Be Done During A PM
Inspection?

• First, always following the manufacturers
  guidelines
• Tasks can be grouped in to four categories
• Inspection
• Cleaning
• lubrication
• Operation checks

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General Checklist Items for most Planned
Maintenance Inspection
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All Equipment

• Turn off furnace and/or air handlers disconnect
• Make a visual inspection of all wire terminals
  and wires
• Check all contactors for signs of wear
• Retighten all accessible screw terminals
• Check fuse holders for tightness
• Turn on furnace and/or handler disconnect

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All Equipment

• Check thermostat operation for accuracy
• Use a good quality thermometer
• Honeywell T87 thermostat can be field calibrated,
  but takes too long
• Cycle equipment on an verify sequence of
  operation is check

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Fan Compartment Belt Drives

• Check belt tension for proper adjustment - 3/8
  1/2 depression per foot of span between pulleys
• If possible, used a belt tension gauge
• Visual inspect belt, bearing and pulley for signs
  of wear
• Visual inspect pulley and drive alignment
• use straight edge or string

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Fan Compartment Belt Drives

• Check pulley and drive set screws for tightness
• Record belt size
• When possible leave an extra belt on the job
• Mark belt size on unit
• Lubricate motor and fan bearings, when possible
• Some motors have sealed bearings and external
  lubrication is not needed

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Fan Compartment Belt Drives

• Check blower wheel for dirt build-up and clean
  when required
• An important maintenance task
• Dirt on blower wheel will reduce CFM delivered by
  fan
• This may be a time consuming task
• May required removing entire drive assembly

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Fan Compartment Direct Drives

• Check blower wheel for dirt build-up and clean
  when required
• Check blower wheel set screws for tightness
• Lubricate motor and fan bearings, when possible

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Fan Compartment Direct Drives

• Visually inspect fan motor for bearing wear by
  spinning fan wheel and notice how it slows down
  and stops
• Check fan motor for excess end play
• Some motors may have up to 1/8 end play
• Check motor bearing for oval shape
• There should be no vertical play with shaft

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Air Filters

• Clean or replaced
• Record size
• Keep a log of all filters sizes used so on next
  inspection the new filters can be order ahead of
  time
• If possible, keep extra filters stored on work
  site
• Make sure to install air filters in the correct
  direction of airflow

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Air Filters

• Some owner may choose to replaced the own filters
  or have their in-house maintenance personnel
  install the filters
• There are many different types of filters
  available - notify the customer of the various
  types so the best filter can be selected for the
  job

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Mechanical Air Filters

• Conventional filters
• Extended-surface filters
• Electrostatic filters
• High-efficiency filters
• Activated carbon filters
• Steel/aluminum mesh filters

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Adjusting The Fan Speed

• Direct drive blowers fan speed can usually be
  changed selecting the appropriate speed tap on
  the motors electrical connection
• White - common
• Black - high
• Yellow - medium high
• Blue - medium low
• Red - low

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Adjusting The Fan Speed

• Belt drives blower fan speed can usually be
  adjusted by changing the flange on the motor
  pulley or changing the pulley
• Adjusting the adjustable pulley flange towards
  the fixed flange will increase the speed of the
  blower

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Always check the amperage draw of the motor after
making any adjust to the fan speed
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Condensing Units

• Turn off air conditioner disconnect
• Make a visual inspection of all wire terminals
  and wires
• Check all contactors for signs of wear
• Retighten all accessible screw terminals
• Check fuse holders for tightness

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Condensing Units

• Turn on disconnect
• Inspect condenser fan motor for bearing wear
• Spin motor and note how it slows down and stops
• Clean the condensate trap on the furnace or air
  handler

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Clean Condenser

• Two types of coil cleaners
• Acidic
• Alkaline
• Using garden hose to rinse
• Do not use too much water pressure can damage
  fins on the condenser coil
• Best to backwash coil - Spray water in opposite
  direction of airflow

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Cleaning Evaporator Coil

• Spray on evaporator coil cleaner
• Condensate water will rinse chemicals off coil
  and down drain
• Drain line needs to be check to ensure that the
  dirt off the coil does not clog the drain line

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Check and Record Voltage

• At Contactor
• Measure across
• L1 L2
• L2 L3
• L1 L3
• T1 T2
• T2 T3
• T1 T3

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Check and Record Voltage

• Check and record voltage drop across
• L1 T1
• L2 T2
• L3 T3
• Check and record amperage draw on each hot leg
• Check voltage at contactor coil

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The Refrigeration System

• Head pressure
• Suction pressure
• Superheat compare with Manu. Specs.
• Subcooling - compare with Manu. Specs.
• Outdoor ambient
• Indoor ambient DB and WB

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TheEND