Burn Baby Burn!
The electrodes of a high-pressure, gun-type oil burner are mounted __________.
Above and ahead of the nozzle
Control circuit voltages are only 24 volts.
True or False
False
What is an economizer used for?
Energy Savings
What is a hot gas bypass circuit used for?
to help release the ice from the evaporator on an ice machine.
On a heat pump reversing-valve solenoid, what is connected to the bottom center tube?
The compressor suction line
Oil-pump pressure should be a minimum of ________ PSI.
100
What safety device protects a small refrigeration compressor from overheating?
Motor overload
If the RLA on a motor is 2 amps, what would be the LRA?
10 amps
Commercial walk-in freezers typically defrost __________. (time)
Every 6–8 hours
What component must always be de-energized during the defrost cycle on a heat pump?
The outdoor fan
The cad cell senses light to prove flame. What should the resistance read when in the presence of the oil flame?
Less than 1500 ohms
Liquid-line filters remove what type of matter?
Moisture and solid particulate
A 120 V primary, 24 V secondary, 48 VA transformer is rated for how many amps?
2 Amps
The duration of a commercial defrost system is typically __________.
15-20 Minutes
Which metering device responds to a changing load condition?
TXV
How many BTU’s are in 100 tons of refrigeration?
1,200,000 BTUs
Suction-line filters remove what type of matter?
Acid, wax, and sludge
Which-pole motor will have the higher RPM?
4-pole, 2-pole, 6-pole, 8-pole
2 pole
On a four-speed motor, which wire to common is high speed, using resistance?
Lowest Resistance
Which metering device is a fixed orifice and is a constant meter?
Cap Tube
Using Ohm’s law, power is also called ______?
Watts
What Pressure closes the TXV
Spring and evaporator pressure
What does PTC stand for?
Positive Temperature Coefficient
Which contacts would be N.O. (normally open)?
Potential relay, high-limit switch, current relay, single-pole switch
Current Relay
To increase the superheat on a TXV one would
Turn the adjusting stem clockwise