Why Maintenance Tasks are Important

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Why Maintenance Tasks are Important

• Produced by
• Joe Marchese

2
Why is it important to turn off the furnace
and/or air handler disconnect before inspecting
the unit?

• This is a safety concern
• inspecting equipment with the
• power on can cause injury to both
• the technician and the equipment.

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Why is it important to visually inspect all
wire terminals and wires?

• Electrical systems that are overloaded
• will heat up and discolor the insulation
• on the wiring. Discolored wiring is
• a sign of a system problem.
• Also, loose connections may cause
• the system to draw more amperage.
• These connections will eventually break, causing
  a system breakdown.

4
Why is it important to check thermostat
operation for accuracy?

• This ensures that the thermostat is maintaining
  the right temperature for the customer. Most
  customers can feel a
• 3 to 5 degree difference in temperature.

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Why is it important to check the cycle rate
switch(es) on the thermostat?

• This ensures that the system is
• cycling on and off correctly,
• with minimum temperature swings.

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Why is it important to check the belt tension
for proper adjustment?

• A loose belt will cause slippage,
• which will cause the system to
• deliver an improper amount of airflow.
• A belt that is too tight will
• cause bearing wear.

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Why is it important to visually inspect the belt,
bearing and pulley for signs of wear?

• Signs of wear indicate that the
• parts need to be changed and
• will fail in the future.

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Why is it important to check the pulley and
drive alignment?

• A misaligned pulley and drive
• may cause the belt to slip off, as well as belt
  and pulley wear.

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Why is it important to check the pulley and drive
set screws for tightness?

• Loose pulley and drive set screws
• will cause the pulley to slip, which will cause
  the CFM delivery to be reduced.
• This will cause damage to the shaft.

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Why is it important to lubricate the motor and
fan bearings?

• Premature bearing failure can be a
• result of a motor that is not lubricated
• as per the manufacturers schedule.

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Why is it important to check the blower wheel
for dirt build-up?

• Dirt build-up on the blower wheel will reduce the
  CFM delivery of the fan.

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Why is it important to visually inspect the fan
motor for bearing wear by spinning the fan
wheel?

• A fan motor that stops quickly is
• a sign of bearing wear or no lubrication.

13
On an electric furnace, why is it important to
check supply voltage?

• Heating elements are rated for a
• specific range of voltages. Voltages outside
  this range will not produce
• the rated BTU output for the furnace.

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On an electric furnace, why is it important to
check amperage on the main line as each heating
element is energized?

• This ensures the heating element(s) are working.

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On an electric furnace, why is it important to
check and record voltage after all heating
elements are energized?

• A voltage drop of 5 or more when elements are
  energized is too high electric line size may be
  too small.

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On an electric furnace, why is it important to
check the temperature rise through the furnace
and adjust fan speed (all furnaces)?

• If a temperature rise occurs that is not within
  the specified range, this indicates that airflow
  delivered by the furnace is not correct.

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On a gas furnace, why is it important to remove
and clean burners and check heat exchanger for
cracks?

• Dirty burners will cause incomplete combustion
  and will produce CO.
• A cracked heat exchanger may cause
• CO to enter the living space.

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On a gas furnace, why is it important to check
burner alignment to ensure no flame impingement
is occurring on the heat exchanger?

• Any impinging of flame will create CO.

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On a gas furnace, why is it important to remove,
clean and adjust the pilot assembly, where
required?

• A clogged pilot orifice may cause a weak pilot
  flame, which may cause the gas valve to fail to
  open on a call for heat.

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On a gas furnace, why is it important to check
and record thermocouple output?

• A thermocouple with a low output voltage will not
  be able to hold in the gas valve.

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On a gas furnace, why is it important to check
and record safety drop-out time?

• This is a safety concern.
• If the pilot does not shut down when
• no flame is present, it will cause raw natural
  gas to enter the living space.

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On a gas furnace, why is it important to check,
record and adjust manifold gas pressure?

• A misadjusted gas valve will cause incomplete
  combustion and
• could cause the unit to produce CO.

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On a gas furnace, why is it important to check
the draft diverter for obstructions?

• An obstruction in the diverter
• will cause products of combustion
• to enter the living space.

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On a gas furnace, why is it important to check
and record stack temperature and draft pressure?

• If the stack temperature is insufficient,
• the products of combustion
• will not be drawn up the chimney.

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On a gas furnace, why is it important to check
and record CO2?

• CO2 is an indication of
• the combustion efficiency.

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On a gas furnace, why is it important to check
and record CO levels?

• A high CO level is a very
• dangerous situation the cause
• must be determined and repaired.

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On a gas furnace, why is it important to record
and check high temperature limit cut-out setting?

• This is a safety item.
• If the furnace is running too hot,
• the burners will shut down before
• there is a problem.

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On a gas furnace, why is it important to check
and record fan switch cut-in and cut-out
temperatures?

• If the fan cut-in is too high, the
• unit could cycle on the limit switch
• also it may cause undue stress
• on the heat exchanger.
• If the fan cut-in or cut-out is too low, the
  customer may complain of cold drafts.

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On an air conditioner, why is it important to
inspect the condenser fan motor for bearing wear?

• A motor that slows down too quickly indicates a
  bearing problem.

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On an air conditioner, why is it important to
clean the condenser?

• A dirty condenser will cause high discharge
  pressures and
• very inefficient operation.

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On an air conditioner, why is it important to
clean the evaporator?

• A dirty evaporator will cause poor heat transfer
  and will cause the coil to frost up.

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On an air conditioner, why is it important to
check and record voltage at the contactor?

• Compressors are rated for a specific range of
  voltages. Voltages outside
• this range will cause damage
• to the compressors motor.

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On an air conditioner, why is it important to
check and record voltage drop across the
contactor?

• This checks the contactor for signs of wear.
  There should be no voltage drop across the
  contactor.

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On an air conditioner, why is it important to
check and record amperage draw on each hot leg?

• A compressor running at amperages outside its
  rated values will likely fail.

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On an air conditioner, why is it important to
check and record the systems head pressure?

• Higher than normal discharge pressure
• is an indication of a system problem.

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On an air conditioner, why is it important to
check and record the systems suction pressure?

• Higher and lower than normal
• suction pressures are indications
• of a system problem.

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On an air conditioner, why is it important to
check and record the systems superheat at the
inlet of the compressor?

• Superheat is one method of checking
• the refrigerant charge of a system.

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On an air conditioner, why is it important to
check and record the amount of subcooling at the
outlet of the condenser?

• Subcooling is one method of checking
• the refrigerant charge of a system.

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On an air conditioner, why is it important to
check the temperature drop through the furnace or
air handler?

• If the temperature drop is not within
• the specified range, it is an indication
• that airflow delivered by the furnace
• is not correct.

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The End