Transcript HVAC Preventative Maintenance Joe Marchese

Air Conditioning
Planned Maintenance
Produced by
Joe Marchese
Why Perform Planned
Maintenance?
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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
How do PM’s keep equipment
at peak efficiencies?
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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.
How Do PM’s Keep Equipment
at Peak Efficiencies?
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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 system’s efficiencies
Poor Indoor Air Quality
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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
Protects Our Environment
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PM inspections will reduce the amount
of refrigerant released in to our
atmosphere.
This will reduce:
• Ozone depletion
• Global warming
PM Inspections Will Also
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Help to even out the workload of a
contracting company
Allow time for scheduled repairs reduces the amount of emergency calls
What is the most important
concern for a service
technician while performing
a preventative maintenance
inspection?
SAFETY
Safety
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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
Safety
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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
Other Safety Concerns
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Rotating & moving part
Sharp objects
Hot and Cold surfaces and work areas
Injury form working with refrigerants
Refrigerant cylinders
Other Safety Concerns
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Gas leaks
Oil leaks
Incomplete combustion - CO poisoning
Ladders
Confines spaces
Personal Protective (Safety)
Equipment (PPE)
Safety Shoes
Safety Goggles
Ear Plugs
Gloves
Who performs PM
inspection?
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Normally it is those technicians starting
out in the industry
Occasionally an experience technician
will perform the inspections
When are PM’s normally
performed?
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Depending on the type of equipment
they can be performed:
– Monthly
– Quarterly
– Semi-Annually
– Annually
How long should a PM
inspection take?
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Mainly depends on:
– the type of equipment
– the detail in which the inspection is
performed
SHORT INSPECTION vs. LONG INSPECTION
How Much Should a PM
Cost a Customer?
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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
What Is The Most Important
Tools Used On A PM
Inspection?
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Your hands
Your eyes
Your ears
Your nose
What Maintenance Items
Should Be Done During A
PM Inspection?
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First, always following the
manufacturer’s guidelines
Tasks can be grouped in to four
categories:
– Inspection
– Cleaning
– lubrication
– Operation checks
General Checklist Items
for most
Planned Maintenance
Inspection
All Equipment
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Turn off furnace and/or air handler’s
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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Turn on furnace and/or handler
disconnect
All Equipment
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Check thermostat operation for
accuracy
– Use a good quality thermometer
– Honeywell T87 thermostat can be field
calibrated, but takes too long
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Cycle equipment on an verify sequence
of operation is check
Fan Compartment
Belt Drives
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Check belt tension for proper
adjustment - 3/8” – 1/2” depression per foot of
span between pulleys
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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
Fan Compartment
Belt Drives
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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
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Lubricate motor and fan bearings, when
possible
– Some motors have sealed bearings and
external lubrication is not needed
Fan Compartment
Belt Drives
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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
Fan Compartment
Direct Drives
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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
Fan Compartment
Direct Drives
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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
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Check motor bearing for “oval shape”
– There should be no vertical play with shaft
Air Filters
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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
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Make sure to install air filters in the
correct direction of airflow
Air Filters
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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
Mechanical Air Filters
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Conventional filters
Extended-surface filters
Electrostatic filters
High-efficiency filters
Activated carbon filters
Steel/aluminum mesh filters
Adjusting The Fan Speed
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Direct drive blower’s fan speed can
usually be changed selecting the
appropriate speed tap on the motor’s
electrical connection
– White - common
– Black - high
– Yellow - medium high
– Blue - medium low
– Red - low
Adjusting The Fan Speed
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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
Always check the
amperage draw of the
motor after making any
adjust to the fan speed
Condensing Units
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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
Condensing Units
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Turn on disconnect
Inspect condenser fan motor for bearing
wear
– Spin motor and note how it slows down
and stops
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Clean the condensate trap on the
furnace or air handler
Clean Condenser
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Two types of coil cleaners
– Acidic
– Alkaline
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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
Cleaning Evaporator Coil
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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
Check and Record Voltage
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At Contactor:
– Measure across:
• L1 & L2
• L2 & L3
• L1 & L3
• T1 & T2
• T2 & T3
• T1 & T3
Check and Record Voltage
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Check and record voltage drop across:
• L1 & T1
• L2 & T2
• L3 & T3
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Check and record amperage draw on
each hot leg
Check voltage at contactor coil
The Refrigeration System
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Head pressure
Suction pressure
Superheat – compare with Manu. Specs.
Subcooling - compare with Manu. Specs.
Outdoor ambient
Indoor ambient – DB and WB
The
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