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G2 Practice Exam - Part 3

G2 Practice Exam - Part 3

Pregunta 1 de 22

1

The temperature of the water returning from the heating loop in a combination system employing a
water heater for domestic hot water and space heating must be:

Selecciona una de las siguientes respuestas posibles:

  • Higher than the outlet temperature from the water heater

  • No more than 5 degreesC below the outlet temperature from the water heater

  • Lower than the minimum temperature required to activate the burner

  • At least the set temperature of the domestic hot water supply

Explicación

Pregunta 2 de 22

1

The components for a copper fin tube, instantaneous water heater are a/an:

Selecciona una de las siguientes respuestas posibles:

  • anti-scald device and a pup control

  • Pump, pump control, flow switch, temperature and pressure relief valve, and a limit control

  • E.C.O. temperature and pressure relief valve, anode, and a dip tube

  • Temperature and pressure relief valve, anode, and a limit control.

Explicación

Pregunta 3 de 22

1

The most likely cause of an intermittent hissing sound “like water dripping on something hot”
coming from a water heater is:

Selecciona una de las siguientes respuestas posibles:

  • An intermittent leak in the flue that seals once the tank heats up.

  • Condensation in the flue passage caused by drawing water from the tank when the hot water
    has been depleted

  • Condensation in the flue passage caused by high humidity in the combustion air supply to the
    water heater

  • Condensation in the flue passage caused by high moisture content in the gas supply.

Explicación

Pregunta 4 de 22

1

Most thermostatically controlled domestic hot water heaters utilize:

Selecciona una de las siguientes respuestas posibles:

  • bi-metallic sensing

  • Rod and tube sensing

  • Liquid filled sensors

  • Vapour filled sensors.

Explicación

Pregunta 5 de 22

1

When determining the position of an air handler and a water heater to be connected for combination heating use, the most important factor to consider from the following list is:

Selecciona una de las siguientes respuestas posibles:

  • Venting of the water heater

  • Water piping for the water heater

  • Duct design for the air handler

  • Water piping to the air handler

Explicación

Pregunta 6 de 22

1

A customer complains that the pilot goes out every once in a while. This is the second service call for this problem this month. When the pilot is reestablished, the closed circuit millivolt test stays steady at 14mV, the magnet drops out at 4mV, what should be done next?

Selecciona una de las siguientes respuestas posibles:

  • Replace the gas valve because the magnet is weak

  • Clean and adjust the pilot and burners

  • Replace the thermocouple

  • Check for another problem such as down draft or pilot position.

Explicación

Pregunta 7 de 22

1

Which of the following is required to determine the size of a circulator pump to be used on a combination heating system employing a water heater?

Selecciona una de las siguientes respuestas posibles:

  • The temperature of the water and the amount of lift in the system

  • The required water flow rate and the head pressure in the complete heating loop

  • The diameter and length of the straight piping in the entire system

  • The temperature and the velocity of the water in both the domestic plumbing system and
    heating system.

Explicación

Pregunta 8 de 22

1

When diluting muriatic acid with water:

Selecciona una de las siguientes respuestas posibles:

  • Add the acid to the water

  • Add the water to the acid

  • Add water to the acid one drop at a time for 10 drops then add the full amount

  • Add acid to the water one drop at a time for 10 drops then add the full amount.

Explicación

Pregunta 9 de 22

1

What should be done if a relief valve is leaking?

Selecciona una de las siguientes respuestas posibles:

  • Remove the valve and clean off the calcium deposits

  • Replace the valve seat and check for the cause of the activation

  • Replace the relief valve and check for the cause of the activation

  • Open a tap and relieve the tank pressure until the flow stops at the relief valve.

Explicación

Pregunta 10 de 22

1

The flow rate of the water passing through a heating coil of an air handler is controlled by the:

Selecciona una de las siguientes respuestas posibles:

  • Aquastat on the water heater

  • Balancing valve on the heating loop

  • Mixing vale on the heating loop

  • Mixing valve on the domestic hot water system.

Explicación

Pregunta 11 de 22

1

Which instrument is used to determine the speed of a direct drive fan motor?

Selecciona una de las siguientes respuestas posibles:

  • A voltmeter

  • A manometer

  • An anemometer

  • A tachometer.

Explicación

Pregunta 12 de 22

1

Which of the following applies if a furnace is used for temporary heat in a residence under construction?

Selecciona una de las siguientes respuestas posibles:

  • The connection from the furnace to rigid pipe is made with a flex connector not exceeding 6 ft in
    length.

  • Plenums must not be installed until construction is complete

  • The furnace must be installed on a finished concrete floor or slab at least 4” thick and 6” larger
    than the base of the furnace.

  • The furnace must be wired in accordance with the electrical code except that an “on” and “off”
    switch is not required until construction is completed.

Explicación

Pregunta 13 de 22

1

From the following list, what is the most probably cause of a service call where a combustion gas odour is detected in the heated space whenever the circulating blower activates?

Selecciona una de las siguientes respuestas posibles:

  • Cracked heat exchanger

  • A problem in the air circulating or distribution system

  • The vent or chimney is plugged

  • The filter requires cleaning or replacement.

Explicación

Pregunta 14 de 22

1

The high temperature limit switch in the circuitry of a conventional residential furnace is wired in series with the:

Selecciona una de las siguientes respuestas posibles:

  • Fan motor

  • Manual fan switch

  • Gas valve

  • Summer/winter switch.

Explicación

Pregunta 15 de 22

1

Which of the following is the best procedure to increase the furnace blower speed?

Selecciona una de las siguientes respuestas posibles:

  • Close up the motor pulley

  • Open up the motor pulley

  • Increase the size of the return air duct

  • Install a higher horsepower fan motor.

Explicación

Pregunta 16 de 22

1

There is a no heat call for the system, use the following…
Terminals at the thermostat reads 24V
Gas valve coil reads 0V
Gas Coil to gas coil common reads 24V
Points across high limit read 0 volts.
Determine which component is open…

Selecciona una de las siguientes respuestas posibles:

  • Gas valve coil

  • Thermostat

  • High limit

  • Transformer

Explicación

Pregunta 17 de 22

1

There is a no heat call for the system. Using the following…
Thermostat terminals read 0V
Gas valve coil terminals read 0V
High limit terminals read 110V
L & N terminals read 110V
Determine which component is open:

Selecciona una de las siguientes respuestas posibles:

  • Gas valve coil

  • Thermostat

  • High limit

  • Motor

Explicación

Pregunta 18 de 22

1

There is a no heat call for the system, use the following…
Thermostat terminals read 0V
Gas valve coil terminals read 24V
Gas valve (thermostat side) to common terminals read 0V
Gas valve (transformer side) to common terminals read 24V
Determine which component is open:

Selecciona una de las siguientes respuestas posibles:

  • Gas valve coil

  • Thermostat

  • High limit

  • Transformer

Explicación

Pregunta 19 de 22

1

What is the recommended location for a cooling coil on a suspended or horizontal furnace?

Selecciona una de las siguientes respuestas posibles:

  • On the return air side

  • On the supply air side

  • On either side of the air circulating blower

  • Cooling coils are not recommended in these applications.

Explicación

Pregunta 20 de 22

1

What is the minimum distance that the vent from a 75,000 Btuh Category 3 furnace may terminate from a door?

Selecciona una de las siguientes respuestas posibles:

  • 1 foot

  • 3 feet

  • 6 feet

  • 10 feet

Explicación

Pregunta 21 de 22

1

What is the minimum distance that the vent from a 175,000 Btuh Category 3 furnace may terminate from a door?

Selecciona una de las siguientes respuestas posibles:

  • 1 foot

  • 3 feet

  • 6 feet

  • 10 feet

Explicación

Pregunta 22 de 22

1

A low water cut off device on an automatically fired hot water heating boiler rated at 350,000Btuh (102kW) is:

Selecciona una de las siguientes respuestas posibles:

  • Not required if a limit control is installed

  • Not required if it is installed in an industrial application

  • Required when any portion of the circulating system is located below the boiler

  • Required only in commercial applications.

Explicación

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