Controls2 Flashcards
What’s a CPR
Crankcase pressure regulator
Encapsulated pressure controllers come with an adjustable setpoint and a fixed differential. True or false
False. Both are fixed
Which heaters are only energized during a defrost cycle?
Defrost heater and condensate pan heater
What’s the main difference between medium and low temperature control circuits
Low Temp control circuits have active defrost methods whereas medium temp systems use off cycle defrost
What kind of thermostat outputs an analog proportional voltage from eg 2-10V
Modulating/proportional thermostat
Combination fan limit controller
Has cut in and cut out response for fans, and has high temp limit
Thermodisk/bimetal disk temp controller
Non adjustable with a fixed 5°F differential
What kind of pressure controller has a fixed setpoint and fixed differential. And usually a manual reset.
Encapsulated pressure controller
Electronic pressure controller experiences an _ change in response to a change in pressure
Impedance
Who lists fusing requirements
CE code (Canadian electrical)
Circuit breakers are used as the first and last line of defense for electrical faults
TRUE
OFC need a resistive heater because
To allow the compressor to start without short cycling
Some zone thermostats have a _ that manages a single independent piece of equipment in a single room
unitary control component
Condenser fan controller
Cycles the condenser fans to maintain a min discharge pressure
Unloader pressure controller
Close on fall/low pressure controllers. Operates unloader solenoids that unloads the compressor through various methods by increasing or decreasing refrigerant or oil pressure to the compressor.
(E.g lifts the top of the screw compressor slightly)
