QUIZLET DECK

Question 1

Lock out relays are used in air conditioning systems to?
Prevent compressor short cycling
As compared to across the line starters, reduced voltage starters:
Reduce starting in rush current
Closed transition starting means
The motor is never disconnected from the line during starting
For maximum safety of equipment, overload relays should be:
manual reset type
Fuses in motor branch-circuits primarily provide:
motor short-circuit protection
Outdoor reset of hot water temperature for heating gives:
Hottest water during the coldest weather
The heating capacity of an air to air heat pump
decreases as outdoor air gets colder
The instrument used for finding humidity levels in the atmosphere is the?
sling psychrometer
Suction line filter drier are usually equipped with gage connections so that pressure drops can be determined why?
So that you can determine when to change the filter drier
The average house line pressure for natural gas is?
7” W.C.
What air distribution system includes both a warm air duct and a cool air duct, and utilizes mixing boxes near the zone to mix the cool air and warm air streams and achieve the desired temperature while delivering air at a near constant volume?
Dual duct
Capacity control on a helical-rotary (screw) compressor is obtained using
Sliding valve
Which of the following reduced voltage starters uses a switching arrangement to connect the windings of three phase motors in different configurations during start to and normal operation
Star delta starters
One type of pressure sensing device uses a flattened metal tube, which is bent into a part circle with one end fixed in place and connected to a system to be measured. The other end of the tube is closed and free to move. An increase in pressure tends to straighten the tube. The movement of the free end of the tube is connected to a dial that reads pressure. This type of gage is called a
Bourdon Tube
With a change in temperature, a thermistor will change
Resistance
In a CSR motor with 10 microfarad run capacitor and 110 microfarad start capacitor, the total capacitance will be _____?
120 microfarads
Electricity results from the movement of tiny negatively charged particles called?
Electrons
What is the maximum safe amperage draw of the secondary winding of a 60VA transformer output of 12V
5 amps
The hot-gas bypass control method, the system component which is bypassed
The condenser
If a refrigerant site glass, shows bubbles you know
Gas in the liquid
A hermetic motor should never be energized, or tested with a megger when in a deep vacuum because
The dielectric strength will be reduced
In order to protect a load safety, limit devices are often wired
In series
In a balance, three phase system, the phase EMFs differ in phase by
120 degrees
Electrical pressure is measured in
Volts
Bellows are used in
Both pressure and temperature controllers
Worn sleeve bearings can be quickly checked by which of these methods?
Try to move shaft at right angle to the bearing
What does a pillow block bearing to do?
Self aligning
The word ___ is used to describe the amount of wobble on a rotating shaft as read by an indicator.
Runout
Which is the correct tool for removing bearings without damaging the shaft?
Bearing puller
Which is the final step of installing a pillow block bearing?
Tighten bearing to the shaft
Which of these is the most important parts of a mechanical seal
Mating seal surfaces
When lubricating large electric motors, the relief plug should be?
Removed
Which of the following is not a cause of premature v-belt failure?
Rotation of motor
After replacing belts and sheaves, which of the following does not need to be checked?
Torque of pillow block bearings
What should you do to increase air flow on a variable pitch pulley installed on a drive side?
Use larger belt to increase the distance between two shafts (increase diameter)
For maximum life expectancy of bearings, the pulley should be installed where?
As close to the bearing as possible
Which of the following is not an efficient method of aligning a single belt drive?
Visual alignment
When checking for shaft alignment on a motor or a pump, which part of the dial indicator is placed against the shaft?
Contact point
The first step to shaft alignment of an open drive compressor is?
Straight edge
Dial indicator measurement are _ inch increments?
001”
Which is the acceptable shaft runout on a 5hp electric motor?
001
Which id the following type of couplings require the most critical alignment?
Rigid
Which of the following types of coupling require a minimum alignment?
Flexible
Which type of flexible coupling insert is shown here?
Spider Type
Which type of coupling is shown here?
Soft torque (tire type)
Which step should be taken before replacing or installing coupling with electric motors?
Lock out tag the motor lubricate the hold down bolts
Which of these is true of three phase alternating current?
The current are out of phase by 120 electrical degrees
What happens to current if the voltage goes up?
Current goes up
Which is the device used in electric circuits to prevent damage from current overloads?
Fuse
How many btu/h will be provided by one watt of electrical energy in a resistance heater?
3.413
What is the maximum safe amperage draw of the secondary winding of a 40 VA transformer with output of 25V?
1.6 amps
What is the acceptable voltage drop across an energized contractor?
O volts
How would one reverse rotation of a three phase motor?
Swap any two legs
A PSC motor has more starting torque than which type of motor ?
Shaded pole
A three phase motor to be used with a part winding starter must have _ windings?
Six
Which is applicable when replacing defective circuit boards?
Replace with a compatible circuit board with all jumpers and switches in proper position
When trouble shooting a control board, you find there is no control power. Which of these is most common cause?
Blown control fuse
The “megger” is an instrument which, when used in conjunction with motor testing, measure which of these?
Dielectric strength of the insulation condition of the centrifugal switch
Which of the following test instruments is used to measure relative humidity?
Sling psychomotor
How can you make an ammeter measure low current levels?
Loop the wire being measured through the amp clamp
A VFD with bypass has improper rotation of the motor during bypass mode but correct when running drive mode. The VFD requires a change of power leads at ___ power?
The Input
What is the purpose of the jump frequency range on a VFD?
To provide faster start up
When troubleshooting a 480v 3 phase starts, approximately what voltage should you find phase to phase?
480V
What is the meaning of closed transition starting? The machine is started with inlet vanes closed.
The motor is never disconnected from the line during starting
As compared to across-the-line starters, reduced voltage starters:
starting current inrush
Why is a surge suppressor used on a contactor coil?
To prevent damage to the control circuit
Contactors contain which two sets of contact
Stationary and moveable
Why should terminal screws be re tightened on a contactor?
It prevents voltage drop and high current overheating wire
White troubleshooting on a call for cooling, it is found that the voltage across a potential relays contacts remain 0 Volts. The compressor then cycles in its internal overloads. What is one possible cause for this?
Closed (WELDED) contacts in the potential relay
What is the meaning of the symbol shown here?
N.C timed on opening
When the motor of a two-wire spring-return actuator is operating, the spring:
Is being wound up
When using a Magnahelic to set up or calibrate a velocity controller, to which port or ports do you connect?
Both low and high pressure ports
Which of the following is the most common instrument to verify flow to a pump?
Paddle switch
Outdoor reset of hot water temperature for heating purposes provides?
Hottest water during coldest weather
Symbol
Temperature
Which of the following devices changes energy from one form to another?
Transducers
A Bourdon-tube is used for which type of measurement?
Pressure
Which type of gauge reads pressure both above and below atmospheric pressures?
Compound
Operation of flame rectification combustion control system is based on which of these principals?
A flame will conduct electric current
How should safety controls be wired?
In series with operating controls
The oil pressure safety control operates on which two pressures?
Oil pump discharge pressure and suction pressure (suction pressure and discharge)
A pneumatic thermostat for a normally closed chilled water valve. What type of action will the thermostat have?
Direct acting
Which of the following is a digital output?
VFD control
Which of the following is not a digital input?
Space temperature
Why should low water cut off controls on a steam boiler be blown down?
Prevents sediment build up which would limit proper operation
Suction gas temperature minus saturated suction temperature equals to?
Superheat
The boiling point of refrigerant in the condenser is the same as?
condensing temperature
In an air cooled system with capacity control, compressor unloading?
Suction to rise and discharge to fall
Which is the response when dirty filters in an air conditioning system reduce the quantity of air flow over the DX coil?
The system capacity will decrease
If mechanical refrigeration and cooling are used for dehumidification, the system may require which of the following?
Reheat
An unrepaired leak will cause which of the following conditions?
High superheat
Which is the only acceptable refrigerant to be used as a trace gas when checking for leaks
R-22
After January 2019, what is the acceptable annual leak rate of a comfort cooling system if the circuit contains more than 50lbs of refrigerant?
10%
What is the purpose of pulling a system into a proper vacuum?
Remove air and non condensable in the system
For what purpose is a cold trap installed in series with a vacuum pump?
Reduce the rate in which water vapor is drawn into the vacuum pumps oil
How often should oil in a vacuum pump be changed?
After 100 hours or when the oil starts to bubble
Which of the following DOT designations would be acceptable to use on a recovery cylinder when recovering R-410A?
4BW400
Which is the fastest way for to recover refrigerant?
Push and pull method
When recovering bad R-12 and R-22, how or where should it be stored?
Specifically marked cylinders
What is cleaning refrigerant to ARI 700 standards called?
Reclaiming
Which is the best way to drive refrigerant from a cylinder into a unit being charged?
Immerse the cylinder in warm water
The refrigerant should be charged as a ___when charging R-410A
Liquid
When calculating superheat for a HFC refrigerant with a large temperature glide and using a P/T chart, which column on the chart is used?
Dew point
A hermetic compressor internal overload senses which of the following?
Compressor motor temperature
Incorrect rotation of a scroll compressor will cause which of these events?
Tripping of the compressors internal protector
Which is a proper way to check rotation of a screw compressor?
Use a phase rotation meter
Which of the following is not an acceptable method for capacity control for a centrifugal compressor?
Liquid line solenoid valve
You could use which of these devices to protect a large condenser against excessive discharge pressure?
Spring loaded pressure relief valve
A constant _ is maintained by the TXV?
Superheat
Which of the following is the correct term for a coil using a TXV, cap tube, or a restrictor?
Direct expansion (DX)
In what form does refrigerant leave the expansion valve?
A mixture of liquid and saturated vapor
The purpose of taking a pressure drop reading across a suction line filter drier is to?
Contaminant loading of the filter drier
Which of these should be used for chemically cleaning a water cooled condenser
An uninhibited chemical
What results when you reduce water flow to a water cooled condenser?
A decrease in the temperature difference between entering and leaving water
An evaporative cooling towers bleed rate is adjusted to maintain?
The desired concentration of total dissolved solids
Which is not an acceptable way for capacity control on a cooling tower?
Basin heater
A customer would would like all their R-22 retrofitted into HFC. Which refrigerant is acceptable?
R-407C
Which of the following oils is most hygroscopic
Polyester oil (POE)
Which of the following is a disadvantage of a VRF system?
Increased installation cost
Which of the following is true of natural gas?
It has an odor added to it to make it detectable
On an intermittent pilot system, when is the pilot light on?
Only during the pilot trial for ignition
Most appliance gas valves require inlet natural gas pressure not to exceed which measurement?
3.5” WC
Watt= 3413 btu/h a 30kw electric heater will produce how many BTUS?
102,390 BTU/H
While working on a make up air unit, the customer notified you that their direct fired equipment just shut down. What may have caused this?
There is an open inter lock between the MAU and the process equipment
Which of the following is a cause leaking to premature heat exchanger failures in gas fired units?
Clogged air filters and loose fan belts
Surface blowdown in a high pressure steam boiler controls which of the following?
Sediments
Low pressure steam boilers are classified as those operating pressures below how many PSI?
15 PSI
The proper installation height of the Hartford loop on a steam boiler?
2-4 inches
To prevent priming in a steam boiler, the horizontal steam main should be a minimum pressure f what distance above NOWL?
24”
All except which of the following are flame proving methods
8Diode
Which type of ignition system uses a pilot flame?
intermittent
Which of the following is not used to size gas regulators?
Type of ignition system
If a gas regulator is located in the boiler room, typical code requires that the regulator vent needs to be piped where?
Outdoors
Electric heaters are composed of which of the following
Resistors
What is the most likely cause if a technician finds that an electric heat element with voltage applied to the element, has no current flow?
Open or burned element
When replacing the element on an electric heater, the tech should verify that the element?
Are not shorted to frame
Which is an acceptable vent material for condensing boilers?
PVC
Outdoor reset of hot water temperature for heating gives:
Hottest water during the coldest weather
A 3-WAY valve having one inlet and two outlets is classified as ___ valve?
Mixing
Which type of valve has the best variable flow characteristics in a hydronic system?
Globe
Which of the following is a function of a pressure reducing valve?
Relieves excess system pressure
Which of the following is not a result of pump cavitation?
Increased head pressure
Which of the following is the most likely cause of cavitation in a pump that is pumping hot water?
Insufficient NPSH
Which is the most common pump used in hydronic systems?
Centrifugal
Installing two pumps in parallel will result in which of the following
No change
What is the purpose of adding glycol to a solar heating system?
Allows adequate freeze protection in low ambient temperature
Where would the ground source heat pump rejected heat load when in the cooling mode of operations?
To the ground loop
What devices used on a hot water source heat pump to maintain adequate head pressure?
Water reg valve
Higher than normal waterloop temperature would lead to which of these?
High discharge pressure
How much heat does a 10 ton WSHP inject into the water loop when fully loaded in the cooling mode?
120,000 BTU
What is the proper method of cleaning a tube and tube type condenser or WSHP?
Chemical clean
Which of these is required on a four pipe system for chilled water or hot water?
Separate coils for heating and cooling
A water coil generally should be piped to provide ___ flow?
Counterflow
What is the differential pressure converted to feet of head across?
62 feet of head
When a float rises in an F&T trap what discharges?
Condensate and steam
Which of these would result in the FNT trap failed, and filled with water
Steam would discharge continuously
What type of trap is normally used on a steam radiator?
Thermostatic
A steam pressure regulator is constructed so that a rise in _ steam pressure reduces the flow of supply steam to maintain setpoint?
Down stream
If used to drip at the end of a steam main, which type of steam trap would require cooling lake
Thermostatic
A steam coil, using modulating steam control valve would require which type of trap?
F&T
Hey, low pressure, one gravity, return steam, heating system is installed on an automatic steam trap is NOT used, which device will prevent a vacuum from performing
Air vent
Which of the following is used to recover the energy that would be lost?
Flash tank
Where is eliminated from a sub atmospheric system by?
Vacuum pump
How do condensate return pumps cycle on?
A float in the condensate tank
Which of the following is not acceptable in a condensate return pump?
Live steam
Condensate return lines should be made of which type of pipe?
Schedule 80 carbon steel
Which device forms a water seal that prevents raw steam from entering and damaging pressure gauges, paper stats, pressure controls, etc.?
Pigtail
A belt driven fan has a 3’ motor sheave pitch diameter, and a 5” fan sheave diameter
1032
The design of the air supply duct will depend on the air velocity but?
Air temperature
Density
Density
Icing in the coils
Icing in the coils
350-450
350-450
It will require enthalpy controls
It will require enthalpy controls
Create higher load and traditional air economizers
Create higher loads than traditional Air side economizers
What scenario would justify the addition of a heat recovery unit?
The building needs outside air make up, but HVAC equipment is marginally sized
In an air-conditioning system free cooling is so called because it eliminates?
Compressor
A damper that must throttle airflow should have which of the following?
Opposed blade operation
Economizer control contains three automatic dampers, one each for?
Return Air
For good air circulation in an office space, without undo danger of drafts
1-3
Economizers can use several types of sensors which of these sensors is considered?
Enthalpy
If Fire stat should have which of these elements?
Non-adjustable
Which of these may cause I duct pressure limit switches to open?
Fire or zone dampers close suddenly
When the freeze stat trips, the outside air damper the chilled water valve and?
Close open open
Which of these devices is needed for proper operation of system with VAV controller?
Static pressure sensor
Which of these conditions can be caused by the overheating of a wrought copper?
Oxidation and distortion of the joint
1/2
1/2
You are soldering copper tube. After the tube and fitting are cleaned and fluxed?
As soon as possible
You may see which of these results if a compressor discharge muffler is not properly installed?
It might trap oil
What should be the pitch of horizontal suction refrigeration piping runs?
Towards compressor
Condensate drain traps must be used on drive-through evaporator coils in order?
Avoid water overflow
Which of these is true of the wall thickness of type K copper tube?
Is greater than type L or M
When copper tubing is being braised, nitrogen, gas candy, purge through the system?
Avoid oxidation inside the tubing
Steam branch line connections should be made from _ of the steam main?
Top
Which of these may be caused by an undersized vapor line in a refrigerant system?
Excessive pressure drop
On a refrigeration system where the evaporator is located below, the compressor piping is sized?
Smaller for higher velocity
Which of these is true when a load is to be lifted with a sling?
All sharp edges should be padded
What should be done with defective, rigging components and hardware?
Removed from service
When connecting rigging to equipment. Where should the connection be made?
Connect according to the equipment manufacturers instructions
Which of the for lifting sling configurations shown here creates the greatest?
The tighter you go is the greatest?
Which method should be used when lifting heavy objects from the floor?
Lift with legs, not the back
Which federal agency is responsible for personal safety?

OSHA

When conducting certifications of lockout procedures which of the following?

None of the above

After opening the disconnect, a service tech must first?

Install lock out tag out device

The clean air act regulations are enforced by which government agency

EPA

Which of these government agency’s regulate the certification of refrigerant cylinders?

DOT

What is the definition of de minimus

Legal term of minimum amount

When handling refrigerants, what protection is required for your eyes?

Chemical or splash goggles

How should skin that comes in contact with liquid refrigerant be treated?

As a burn

A cylinder recovery tank with a dot service rating of _ psig is required for 410a?

400

Find the area in sq ft of an 18” round duct

Pi r squared 3.1416x9 squared

What is a pumps maximum theoretical lift?

34 feet

A ton of refrigeration is equal to all except which of the following?

15,000 BTUH

Choose the form of water with the largest BTU per pound

Latent heat of vaporization

How many BTU’s are absorbed by the water when one pound of water a 212 degrees?

970.3

The symbol shown here?

Temperature

How would terminal a be labeled

A

Which of the following is not a required part of the work order

Wholesale cost of parts

When contracting a manufacturer regarding packaged parts for a rooftop unit?

Model and serial numbers

Which of the following is not a part of your responsibility relative to your work?

Keeping to yourself and not bothering others

Which of the following is true of a dirty and unkept service van?

It is unprofessional and inefficient

What is the last thing you should do before leaving the job site?

Have the work order signed

Which of the following is not acceptable with the customer?

Complaining about company issues

The device which forms a water seal that prevents rusting from entering and damaging pressure, gauges, vapor, stats, pressuretrols, etc. is?

Pigtail

The boiler return line is connected to the steam main by:

Equalizing line

The device which prevented vacuum from forming in a low pressure gravity return steam heating system for automatic control is not used is a?

Air vent

The steam flow into radiators in a one pipe gravity, return steam heating system can be controlled by?

Installing an air vent with a different air venting capacity

The length of the pipe connection that is needed to overcome the pressure drop in a one pipe gravity return steam heating system and return condensate to the boiler is?

28 inches

In a 15 gravity return steam heating system, the main event should be installed?

15 to 18 inches back from the end of the last steam carrying main.

The thermostat steam trapped that fails in the closed position would cause a heating unit to become?

Waterlogged

If the float in FNT trap filled, with water the trap would?

Discharge condensate continually

If you used to drip the end of a steam main, the type of steam trap that would require a leg is a?

Thermostatic

In a two pipe, Bradley return steam system. The device that prevents raw steam from entering the pipe is a.

Steam trap

The pump motor on a condensate receiver is usually started by?

A High water condition in the receiver

In order to return condensate to a boiler the height of the water column needed to overcome the pressure drop in a two pipe gravity return system is?

28 inches for each pound of pressure the boiler is producing

The pump motor on a boiler feed pump is started when there is?

A low water condition in the boiler

The device that could be used to regulate the discharge pressure of a condensate pump is a?

Plug cock

The device used to activate the vacuum pump in a vacuum steam heating system when there is a loss of vacuum in the system return piping is the?

Vacuum pump

Device which can be used to elevate, condensate, vacuum steam heating system is a?

Lift fitting

The device that is incorporated into a vacuum steam heating system to protect the vacuum pump from creating to low of deep vacuum is a?

Vacuum breaker

In a vapor steam heating system condensate is returned to the boiler by means of a?

Boiler return trap (gravity)

Air is eliminated from a vapor steam system by?

Air eliminator

The device that is used to maintain a pressure differential between the supply and return piping and sub atmospheric steam heating system is a?

Differential controller

Air is eliminated from a sub atmospheric system by?

Vacuum pump

The device that controls the steam pressure on the supply side of a sub atmospheric steam heating system is a?

Control valve

Superheated tubes are protected from warping or burning out by?

Circulating steam through them

To increase the life of a furnace, repair factory water to boilers are equipped with?

Water walls

When steam is super heated, it’s?

Temperature is increased with no increase in pressure

soot should be removed from fire tube boilers?

For better heat transfer

Thermostatic traps are open and closed?

Flexible bellows

In a float in thermostat trap, the float rises to discharge?

Condensate

Condensate in steam lines would result in?

Water hammer

The types of traps normally used on steam radiators are?

Thermostatic traps