Unit 32 Oil Heat

a flu Line Filter is located between

Supply tank and the pump

the stack switch or relay

both A and B are correct

excess air supplied at the burner to ensure that there will be

enough hydrocarbons for complete combustion

to perform combustion efficiency tests a hole must be made

in the flu on the furnace side of the draft regulator

a condensing oil furnace achieves part of its higher efficiency because of a______ Exchange

latent heat

Define a natural refrigerant

still used to cool foods today

a air temperature rise check is performed to determine

whether or not the airflow is correct across the heat exchanger

Three disadvantages of parallel compressor systems are ___,___, and ___

-large leaks will result in the failure of multiple remote units -one motor burnout can result in acid formatin in system -extensive cleanup procedure required

the ignition Transformer steps up the 120v residential voltage to approximately____________ v

10000

how much heat is produced when two gallons of number 2 fuel are burned

140000 BTU

a booster pump is often needed when oil supply tank is ________below the oil burner

15 ft or more

of the six regular grades of oil fuel the grade most commonly used in residential and Light commercial heating systems is number

2

assuming 50% excess air is being provided how many cubic feet of air will be supplied to a oil burner to burn 1 lb of fuel oil

288 cubic feet

assuming perfect combustion how many pounds of oxygen are required to burn 1 pound of fuel oil

3.00lb

What is the critical point of carbon dioxide

31.1 degrees Celsius

What is the triple point of carbon dioxide

5.2 atm

how much excess air is supplied to the system to ensure that complete combustion

50%

Three advantages of unitary, stand-alone refrigeration modules in supermarket refrigeration are ____, ____, and ____

75% less piping, lower installion costs, and requires 75% fewer braze points

Exactly matching the refrigeration load with the capacity of of refrigeration compressors is referred to as A. capacity control B. load shedding C. load paralleling D. load matching

A. capacity control

When the compressors are located in the equipment room, the piping is routed A. in floor chases or in plastic pipes under the floor B. in suspended ceilings C. detween the walls D. in back of walls

A. in floor cases or in plastic pipes under the floor

Define a parallel compressor system and list five advantages of these systems

Apply two or more compressors to a common sucion header,a common discharge header, and a common reciever. Five advantages: -load matching -diversification -flexibility -higher efficencies -lower operating costs and -less compressor cycling

When one large compressor is used, what desirable feature should it have A. discharge muffler B. suction muffler C. cylinder unloaders or variable-speed drive D. hot gas bypass

B. suction muffler

Explain the function and advantages of a secondary-fluid system

Circulates antifreeze solution to refrigerated cases and offers many advantages over a conventional refrigeration system

How are conditions maintained in open display cases when there are high shelves

Conditions are maintained because the refrigerated air is heavy and settles to the bottom

What special precautions should be taken with drain lines and walk-in coolers A. freeze protection B. trapping to prevent air from being pulled in C. downward sloping D. all of the above

D. all of the above

Large or small compressors on parallel compressor racks, which are usually dedicated to the coldest cases, are called A. satellite compressors B. remote compressors C. booster compressors D. both a and c

D. both a and c

What special valve is used in a refrigerant air drier A. four way valve B. defrost valve C. three way valve D. hot gas bypass valve

D. hot gas bypass valve

What type of defrost is normally used for vending machine medium-temperature applications A. electric B. hot gas C. off cycle D. none of the above

D. none of the above

How is defrost accomplished when the equipment room is in the back and the medium-temperature fixtures are in the front

EPR valves

True or false: the two types of defrost used with low-temperature fixtures are hot gas and electric defrost

False

Explain how the oil seperator, oil reservoir, presssure differential valve, and oil-level regulators work together to maintain the correct oil level in parallel compressors

From the oil reservoir, the oil passes to the oil-regulator float valve, which is located in the sightglass, level regulator senses crankcase oil levels and opens/ closes as necessary. PDV maintains the pressure differential

Explain the main idea behind pressurized liquid systems, and list their advantages

Offers a different way to subcool liquid refrigerant this helps in overcoming any pressure drops in liquid line to prevent premature flashing of the liquid before entering the metering device

The two broad categories of display cases are ___ and ___

Open and closed

What is meant by carbon dioxide having a critical point

Supercritical carbon dioxide is a fluid state of carbon dioxide where it is held at or above its critical temperature and critical pressure.

What is meant by carbon dioxide having a triple point

The triple point of any substance is the temperature and pressure where solid, liquid and gas forms can all three coexist in equilibrium, i.e. the amount of gas, liquid and solid won't change.

and oil deaerator

allows a one pipeline oil delivery system to operate as a to pipeline oil delivery system

What holds up the structure of a walk-in cooler

aluminum of galvinized sheet metal, when panels pull together become a prefabricated structure

What are mullion heaters

an electric heater mounted inside the mullion to prevent moisture from forming in humid weather

if oil is broken up to farm tiny droplets it is called

atomization

what hydrocarbons unite rapidly with oxygen it is called

combustion

The two methods for rejecting heat from from refrigerated cases are ___ and ___

evaporative condensors and cooling towers

an upflow furnace

has the return air at the bottom

The three temperature ranges for refrigeration systems are ___,___, and ___

low, medium, and high

A(n) ___ varies the frequency of and electrically altered sine wave, which affects the speed of alternating current motors

power inverter

What is the function of the microprocessor-based controller in the parallel systems

processes voltage signals

the cad cell is a safety device that

senses light in the combustion chamber

What is the functin of the pressure transducer in parallel compressor systems

signals the controller on the parallel compressor rack for capacity steps

the pump on a residential gun type oil burner is a ____________ pump

single stage or two stage

the motor on a residential gun type oil burner is usually a ___________ motor

split phase multi horsepower

the fuel oil enters the orifice nozzle through the

swirl chamber

the net stack temperature is

the difference between the flu temperature in the temperature of the air surrounding the furnace

the circular direction of air in the air tube is in _______ direction as the fuel oil motion

the opposite

the heat exchanger in a forced air oil fired furnace

transfers heat from the flue gases to the air to be heated and circulated and keeps them separate

the cad cell is often coupled with a

triac

What is the difference between an even and uneven parallel compressor system

uneven is different sized compressors, and all compressors are equal on an even system

Define a synthetic refrigerant

uses mechanical and chemical processes