DEPARTMENT - AIR CONDITIONING|
Residential Preventive Maintenace
Basic maintenace for a household
AC should be done every 3 months that the AC unit is being used. This includes
replacing the air filter, checking the fans and belts, clearing the drain line
and making sure the area around the condenser is clear.
| Air Filter|
Turn the power off to the furnace, and look for the filter
access panel. The air filter can be internal or external to the furnace. Look
at where the return air duct meets the furnace and look for a long narrow opening
or access. If the filter is internal, than remove the fan access door, normally
below the burner access panel.
Throwaway filters should be changed every
three months or more often if required. When you change the filter, if it appears
to be very dirty, or the dust and dirt are falling off like a rain shower then
change the filter more often. If you do not maintain your filter your evaporator
coil will begin to look like this one to the left, which is completely plugged.
the coil is located inside the ducting it is very difficult and expensive to clean
properly, keeping it clean in the first place is much easier.
Plugged Evaporator Coil
The evaporator drain should have a trap
big enough to stop water from being sucked into the unit and the trap should be
removable for cleaning. Remove the trap and clean it at least once a year. This
will prevent water from overflowing onto the furnace and fan. The picture to the
left shows an evaporator drain that has not worked properly for years. Causing
damage to the structure, and reduces the air quality. The mould and the slim that
are growing here and being blown through out the building by the furnace fan.
The damage to the coil and casing cannot be properly repaired and the unit needs
to be replaced.
Turn the power off to the outdoor condensing unit- There should
be a service disconnect switch directly beside the equipment. Remove the access
cover to the electrical compartment and have a look at the components. There should
be at a minimum, a compressor contactor and a capacitor inside. Check for any
signs of overheating on the wires, contactors or terminal. Overheated or lose
connections will shorten the life of the compressor. Some pitting on the contactor
is acceptable, but if they point appear charred or burnt right off or if the brass
on the contactor discoloured. Replace the contactor if necessary, a faulty contactor
can easily damage compressor, which would have to be replaced.
Burnt Compressor Contactor
Fan The fan compartment is the lowest panel on an up-flow furnace
and the highest panel behind the vent connector on a down-flow. Turn the power
of to the furnace at the service switch, if you cannot locate a service switch,
turn the breaker off or remove the fuses before removing the panel. If the fan
is belt driven, then check the pulley and belt for wear. Feel the inside groove
of the motor pulley for ridges. The walls of the pulley should feel smooth, without
raised ridges. If the fan belt is has been slipping, if will quickly wear down
the pulley and reduce the fan speed. This can cause the coil to freeze and damage
the compressor. Remove the fan belt, and check the bearings on the motor and blower.
They should rotate freely, and quietly If it has a grinding sound to it or feels
tight then new bearing or motor will be need. On direct drive motors the bearing
wear can be heard when the fan is running. Replace any dried or cracked fan belts.
When adjusting the fan belt do not over tighten the belt. It should be just tight
enough not to slip, if it is too tight, it will damage the bearing. Too loose
and it will slip and squeal. If you are replacing the belt, recheck the tension
after 24 hours. New belts can loosen after the first few hours of operation.
both belt drive and direct drive fans, check the condition of the fan blades.
The fan on the right has been running without a proper filter. This will sharply
reduce the airflow. Remove the fan to from the furnace for proper cleaning. If
it can't be removed, then clean the fan in place by using a vacuum and a small
brush. Be careful not to damage the balancing clips on the fan blades else you
will need to buy a new fan wheel. After the airflow as been return to normal,
there will likely be loose dirt blown out of the ductwork when you turn the fan
back on. The increased airflow will pick up dirt from the supply air ductwork
and discharge it out the supply grills. A good ducting cleaning company can help
prevent this and they should be able to clean the evaporator and the fan as well.
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