Air Conditioning Planned Maintenance Produced by Joe Marchese

Why Perform Planned Maintenance? n To keep the equipment performing in good condition and at peak efficiencies n They help to maintain good indoor air quality n They help protect our environment

How do PM’s keep equipment at peak efficiencies? n Clean coils keep the heat transfer rate and temperature difference between the refrigeration and the cooling medium at optimum levels. n Running system with an undercharge of refrigerant will cause the system to run longer & not to its design efficiencies.

n Poor electrical connects can cause the system to work harder n Improper gas combustion will decrease the efficiency of a gas appliance & may cause CO to be produced n 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 n Can lead to Lung/Respiratory illnesses n Can inflame allergies n Can cause damage to interior furnishings n Stagnant water left in an appliance can be a breeding ground to biological contaminants. –Such as Legionnaire's Disease

Protects Our Environment n PM inspections will reduce the amount of refrigerant released in to our atmosphere. n This will reduce: Ozone depletion Global warming

PM Inspections Will Also n Help to even out the workload of a contracting company n 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 n Good safety practices helps to avoid injuring yourself & prevents damage to the equipment. n Must be first on your mind at all times n Always remove any loose items you may be wearing when working around equipment with moving or rotating parts

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

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

Other Safety Concerns n Gas leaks n Oil leaks n Incomplete combustion - CO poisoning n Ladders n Confines spaces

Personal Protective (Safety) Equipment (PPE)

Safety Shoes

Safety Goggles

Ear Plugs

Gloves

Who performs PM inspection? n Normally it is those technicians starting out in the industry n Occasionally an experience technician will perform the inspections

When are PM’s normally performed? n Depending on the type of equipment they can be performed: –Monthly –Quarterly –Semi-Annually –Annually

How long should a PM inspection take? n 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? n 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? n Your hands n Your eyes n Your ears n Your nose

What Maintenance Items Should Be Done During A PM Inspection? n First, always following the manufacturer’s guidelines n Tasks can be grouped in to four categories: –Inspection –Cleaning –lubrication –Operation checks

General Checklist Items for most Planned Maintenance Inspection

All Equipment n Turn off furnace and/or air handler’s disconnect n 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 n Turn on furnace and/or handler disconnect

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

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

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

Fan Compartment Belt Drives n 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 n Check blower wheel for dirt build-up and clean when required n Check blower wheel set screws for tightness n Lubricate motor and fan bearings, when possible

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

Air Filters n Clean or replaced n 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 n Make sure to install air filters in the correct direction of airflow

Air Filters n Some owner may choose to replaced the own filters or have their in-house maintenance personnel install the filters n 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 n Conventional filters n Extended-surface filters n Electrostatic filters n High-efficiency filters n Activated carbon filters n Steel/aluminum mesh filters

Adjusting The Fan Speed n 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 n 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 n Turn off air conditioner disconnect n 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 n Turn on disconnect n Inspect condenser fan motor for bearing wear –Spin motor and note how it slows down and stops n Clean the condensate trap on the furnace or air handler

Clean Condenser n Two types of coil cleaners –Acidic –Alkaline n 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 n Spray on evaporator coil cleaner n Condensate water will rinse chemicals off coil and down drain n Drain line needs to be check to ensure that the dirt off the coil does not clog the drain line

Check and Record Voltage n At Contactor: –Measure across: L1 & L2 L2 & L3 L1 & L3 T1 & T2 T2 & T3 T1 & T3

Check and Record Voltage n Check and record voltage drop across: L1 & T1 L2 & T2 L3 & T3 n Check and record amperage draw on each hot leg n Check voltage at contactor coil

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

The END