NATE Light Commercial Refrigeration
What is the MOST important aspect about installing a rooftop package
unit? correct
answers The roof will support the
weight
What could be at fault of an air cooled system that operates 50°F
over ambient correct answers An overcharge, air in the system, or air re-
temperature?
circulating
over the
condenser
Where should the sensing bulb on a TXV be located? correct answers As
close to theas possible on a
evaporator
horizontal line
When a transformers secondary windings are wired in parallel, it is
important to wire correct answers In phase with each
them
other
If a single phase compressor is cycling on its overload protector, what
should be correct answers Voltage input, test capacitors, start relays,
checked?
and motor
winding
s.
What is the maximum pressure drop across an R-404A suction line filter
dryer? correct
answers 2 PSI (2 degree saturation
temp)
What type of maintenance do water cooled condensers require? correct
answers
the Clean
coil with scale remover and adjust the
water valve
If a CSR motor starts and operates with a high amperage, what could
be at fault?
correct answers A faulty run
capacitor
What causes excessive head pressure on water cooled condensers? correct
answers
Fouled condenser water, dirty water cooled condenser, over charge and air
trapped in
the
condenser
What happens during a hot pull down? correct answers The refrigeration
system
hard andworks
for low temperature systems a CPR (crankcase pressure regulator)
is used to
prevent compressor
overloading
What will ice on the ceiling and floor of a walk-in freezer typically
indicate?Acorrect
answers plugged drain line or a defective drain pan
heater
Name some ways to maintain head pressure during low ambient
conditions
answers correct
Reduce the airflow over the condenser by a reverse acting high
pressure
switch, an electronic fan speed control, or louvers or use a head
pressure control
regulating valve (HPR) to back flood the
condenser
What is the MOST important aspect about installing a rooftop package
unit? correct
answers The roof will support the
weight
What could be at fault of an air cooled system that operates 50°F
over ambient correct answers An overcharge, air in the system, or air re-
temperature?
circulating
over the
condenser
Where should the sensing bulb on a TXV be located? correct answers As
close to theas possible on a
evaporator
horizontal line
When a transformers secondary windings are wired in parallel, it is
important to wire correct answers In phase with each
them
other
If a single phase compressor is cycling on its overload protector, what
should be correct answers Voltage input, test capacitors, start relays,
checked?
and motor
winding
s.
What is the maximum pressure drop across an R-404A suction line filter
dryer? correct
answers 2 PSI (2 degree saturation
temp)
What type of maintenance do water cooled condensers require? correct
answers
the Clean
coil with scale remover and adjust the
water valve
If a CSR motor starts and operates with a high amperage, what could
be at fault?
correct answers A faulty run
capacitor
What causes excessive head pressure on water cooled condensers? correct
answers
Fouled condenser water, dirty water cooled condenser, over charge and air
trapped in
the
condenser
What happens during a hot pull down? correct answers The refrigeration
system
hard andworks
for low temperature systems a CPR (crankcase pressure regulator)
is used to
prevent compressor
overloading
What will ice on the ceiling and floor of a walk-in freezer typically
indicate?Acorrect
answers plugged drain line or a defective drain pan
heater
Name some ways to maintain head pressure during low ambient
conditions
answers correct
Reduce the airflow over the condenser by a reverse acting high
pressure
switch, an electronic fan speed control, or louvers or use a head
pressure control
regulating valve (HPR) to back flood the
condenser
