Air ConditioningPlanned Maintenance

Produced by

Joe Marchese

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

How do PM’s 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.

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

How Do PM’s Keep Equipment at Peak Efficiencies?

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

Protects Our Environment

PM inspections will reduce the amount of refrigerant released in to our atmosphere.

This will reduce:• Ozone depletion• Global warming

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

What is the most important concern for a service

technician while performing a preventative maintenance

inspection?

SAFETY

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

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

Other Safety Concerns

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

Other Safety Concerns

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?

Normally it is those technicians starting out in the industry

Occasionally an experience technician will perform the inspections

When are PM’s normally performed?

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

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

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

What Is The Most Important Tools Used On A PM

Inspection?

Your hands Your eyes Your ears Your nose

What Maintenance Items Should Be Done During A

PM Inspection? 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

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

Turn on furnace and/or handler disconnect

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

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

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

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

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

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

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

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

Mechanical Air Filters

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

Adjusting The Fan Speed

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

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

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

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

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

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

Check and Record Voltage

At Contactor:– Measure across:

• L1 & L2• L2 & L3• L1 & L3

• T1 & T2• T2 & T3• T1 & T3

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

The Refrigeration System

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

TheEND