2nd Semester Final HVAC

What is a load?

Anything that uses power

Compund is ____?

Blue

Most tubing cutters have a ____, which can be used to remove burrs from cut tubing.

Reamer

What color wire is for cooling on a Thermostat?

Yellow

A heat pump that uses the outside air as a heat source or a heat sink for producing the desired temperature in a conditioned space is a ____ heat pump.

air source

What should te voltage reading be on a load switch?

0

Operation sequences of a gas furnace.

1. Thermostat/ Call heat 2. Inducer 3. Pressure switch 4. Ignitor 5. Gas valve 6. Flame sensor 7. Blower

When you are flaring tubing, place the end of the tubing approximately ____ above the surface of the flaring block.

1/16"

What is the limit for Temperature drop?

15-22

How wide so you cut a piece of sheet metal to make S-Lock?

3 inch

What is the minimum Microns we pull when doing a vacuum?

500 Microns

What is the maximum amount of refrigerant that a recovery cylinder should contain?

80% water capacity by weight

What is the limits for superheat?

8° to 15°

According to ASHRAE classification for refrigerants for refrigerants, the classification for the least toxic and least flammable refrigerants is ____.

A1

Solar panels used in conjunction with heat pump systems ____.

Absorb heat from the sun

We measure Intensity in what unit of measurement?

Amps

Due to their high ozone depletion potential, ____ refrigerants were targeted first for phaseout by the Montreal Protocol

CFC

On a heat pump what is the middle schrader connection called?

Common Suction Line

When the capillary tube serves the function of both the liquid line and the metering device, it is connected between the evaporator and the ____.

Condenser

A pressure temperature curve shows that pressure and temperature are ____ in a refrigeration system.

Directly related

What is the first thing you do after power is shut off when changing a Capacitor?

Discharge

Voltage stay the same or drops in a series circuit?

Drops

What happens to amps in a parallel circuit?

Drops

Which of the following statements about charge compensator tanks is false?

During the cooling mode, the gas line cools liquid refrigerant in the tank.

The thermostatic expansion valve provides a high flow rate as the evaporator ____.

Empties

Low-side float metering devices control the flow of liquid refrigerant into the ___.

Evaporator

When a heat pump is operatong in heating mode, the outdoor coil functions as a ____ by absorbing heat.

Evaporator

The seperation of a zeotropic blend's individual refrigerants during phase change is known as?

Fractionation

A heat pump that uses the earth as a heat source or a heat sink for prodycing the desired temperature in a conditioned space is a ____ heat pump.

Ground source

What divides the combustion gases from the heated air in a gas furnace?

Heat exchanger

Name the first 2 rules of Thermodynamics.

Heat travels to cold Energy cannot be created or destroyed

Which type of gauge is designed to read pressure values on a single continuous scale up to 800 psi?

High-pressure gauge

If the entire refrigerant charge has leaked out if a system, then a ____ can be used to pressurize the system to test for leaks.

Inert gas

Which of the following statements about flow check pistons is false?

It meters refrigerant passing through it in either direction

What does Close mean on a switch or relay

It's "on" / power is passing through

Metering devices that can change their orifice size to account for changes in cooling loads are referred to as _____ metering devices.

Modulating

Explain what N/O and N/C mean on a switch or relay.

Normally open Normally closed

The ____ of the capillary tube determines how much the pressure drops between the condenser and evaporator.

Number of turns Length Inside diameter

Which of the following statements about heat pump compressors is false?

One way filter drier protect the compressor from liquid slugging.

Capillary tubes may become plugged due to wax build-up from ____ in the system.

Overheated coil

What does Line mean in a circuit or on a load?

Power in

The process of pumping a system's entire refrigerant charge into the liquid reciever is called a ____.

Pump-down

Which zeotropic refrigerant blend is used as a replacement for R-22, but operates at a higher temperature and pressure?

R-410A

Which type of comoressor is most similar in construction to an automobile engine?

Reciprocating

Refrigerant ____ is the process of removing refrigerant from a system and storing it in a cylinder.

Recovery

Which type of refrigerant cylinder is gray on the bottom and yellow on top?

Recovery

What color is a Direct Reding Gauge?

Red

Which of the following is a thin strip of spring steel that bends to open a valve passage and returns to flat shape to close the passage?

Reed Valve

A four way manifold controlled by a solenoid valve is a ____.

Reversing valve

Most HVACR systems use a standard TXV with a _____.

Sensing Bulb Single Inlet Songle Outlet

A condition in which too much refrigerant is in the evaporator and can be drawn into the compressor is referred to as liquid ____.

Slugging

A ____ valve is an electromagnet with a movable core that opens and closes a fluid passage.

Solenoid

4 Parts of a circuit

Source Path Load Switch

With a TXV we measure Subcool or Superheat?

Subcool

If heat is added to a saturated vapor and raises the vapor's temperature above its boiling point, the heat is referred to as ____.

Superheat

What 2 places do you take temperature drop on a furnace?

Supply and return air

Which of the following statements about a heat pump operating in cooling mode is false?

The compressor pumps high-pressure refrigerant vapor into the indoor coil

Electromotive force is measured in what?

Volts E=I×R

What is the Formula to determine how much refrigerant can be put into a recovery bottle?

WC×.8+TW

On a heat pump system with a two piston-type fixed-orifice metering devices, one piston meters refrigerant flow during the _____ mode and allows free flow during ____ mode.

cooling, heating

Smaller heat pumps use a ____, which uses the direct action of the solenoid plunger to move the pistob and sliding section of tubing inside the valve.

direct-acting reversing valve

A ground-source heat pump that circulates refrigerant through an outdoor coil that is placed in direct contact with the earth is a ____ heat pump.

direct-expansion

TXV's have a sensing bulb mounted on the ____ of the evaporator.

inlet

The thermostatic expansion valve is operated by a pressure difference betweent the sensing bulb pressure and the ____ pressure.

low-side

To create the necessary pressure difference in a refrigeration system, a ____ device is installed between the liquid line and evaporator.

metering

When a refrigeration unit is off, the temperature of the condenser is ____ the temperature of the refrigerant.

the same as

A heat pump that circulates water through a secondary circuit that is placed underground or underwater is an ____ heat pump.

water source