1) P 837 The four types of gas furnace air flow patterns are_
upflow, downflow, horizontal left and horizontal right.
2) P 838 Describe the function of a multipoise or multipositional furnace.
Multipoise or multipositional fur
1) (558) A compressor increases suction pressure level to the discharge pressure level. It lifts low the low
pressure gas from the suction side of the system to the discharge side of the system. (vapor pump)
2) (560) reciprocating, screw, rotary, scroll,
Automatic expansion valve (AXV) a refrigerant control valve that maintains a constant pressure
in an evaporator. Sometimes abbreviated AEV.
Balanced-port TXV a valve that will meter refrigerant at the same rate when the condenser
1) Condensers must be cleaned to remove the minerals and scale deposits in them. In
cleanable condensers, the tubes can be cleaned by using brushes. In this type of condenser,
the flange can be removed to clean it. Shell and coil condensers are closed and
Back electromotive force (BEMF) this is the voltage-generating effect of an electric motors
rotor turning within the motor.
Bearings a device that surrounds a rotating shaft and provides a low-friction contact surface to
1) (469) A. replace it
2) (471-72) The parts that can be replaced on a contactor are the contacts (both moving
and stationary), the holding coil, and the contact holding springs. The components of a
starter that may be replaced are the contacts
Chapter 18 Review Questions
1) (450) Power supply, work requirements, motor insulation type or class, bearing types, mounting
characteristics, and cooling requirements all influence the selection of an electric motor.
2) (451) A. voltage B. current capaci
(482-3) C. a wire in one winding is broken
(482) B. a winding conductor is worn bare & touches another part of the conductor that is also
(482) C. ohmmeter
(484) B. increase
(485) A. megoh
Chapter 17 review answers
(422) 115 V & 230 V
(425) Centrifugal switch (electronic start switch)
(426) a start capacitor
(427) a run capacitor
(433) The large metal mass of the motors rotor turning at high speeds with motor
A -Head pressure
2) 598 Stainless Steel
3) 595 Superheat
4) 601 liquid, vapor, cross liquid, cross vapor
5) 594 D-evaporator outlet
6) 606 When evaporating piping circuits become very long with a lot of U Bends or
a refrigerant distributor is used.
1) P 818 The material often used to manufacture electric strip heater coils is.
Nichrome (nickel chromium)
2) P 818 Portable or small space heaters with glowing coils transfer heat by _.
3) P 820 Baseboard heaters tr
Electric heat relay a relay that, when its coil is energized, will initiate a heat cycle.
Ladder wiring diagram a wiring diagram that separates each individual circuit of a
piece of equipment or system into separate, often hor
1. Mark your board with gray tape & names.
2. Ask instructor for correct screws.
3. Layout lamp holders
(make sure you have room for everything)
4. Layout contactor & relays
(instructor will give you parts)
6. Wire in low voltage including
Pump Down/Change Outdoor Unit/Split System
Hook up gauges
Bleed high & low
Turn on system
Close high side valve
Watch gauges go to 0 psig
Close low side v
Aeroseal is a company that seals the ductwork on your AC
system. They seal it from the inside out. Aeroseal is made out of
the same thing as bubblegum. They have been in HVAC/R since
2013. Money magazine said that this is one of the top 3 things to
Diffuser is the terminal or end device in an air-distribution system that directs air
in a specific direction using louvres.
Friction Loss is the loss of pressure in a fluid flow system (air or water) due to the
friction of th
Cold Trap is a device to help trap moisture during the evacuation of a refrigeration system.
Degassing is removing air and other non-condensable gasses from a system using a vacuum pump.
Dehydration is removing moisture from a