10+ SGS Interview Questions and Answers

There are mainly two types of pumps used in HVAC systems: centrifugal pumps and positive displacement pumps.

• Centrifugal pumps are commonly used in HVAC systems for circulating water or other fluids. They are efficient and have a simple design.

• Positive displacement pumps are used for applications where a specific flow rate is required, such as in hydronic heating systems.

• Other types of pumps used in HVAC systems include axial flow pumps, mixed flow pumps, and regenerative turb...read more

PPM stands for Planned Preventative Maintenance. It should be done every 3-6 months for chillers, AHUs, pumps, and other equipment.

• PPM is a proactive approach to maintenance to prevent breakdowns and prolong equipment life.

• Chillers, AHUs, pumps, and other critical equipment should undergo PPM every 3-6 months.

• Regular PPM helps in identifying potential issues early and ensures optimal performance of the equipment.

• PPM involves tasks like cleaning, lubricating, inspecting, and t...read more

When the pump motor is heated, it can lead to decreased efficiency, increased wear and tear, and potential damage to the motor.

• Decreased efficiency: Heat can cause the motor to work harder, leading to decreased efficiency in pumping water.

• Increased wear and tear: Excessive heat can accelerate the wear and tear of the motor components, reducing its lifespan.

• Potential damage: If the motor overheats, it can lead to permanent damage such as burnt windings or insulation failure.

• Lo...read more

A chemical dosing system in a chiller is used to introduce specific chemicals into the water to prevent scaling, corrosion, and biological growth.

• It helps maintain the efficiency and longevity of the chiller system.

• Chemicals like corrosion inhibitors, biocides, and scale inhibitors are commonly used.

• The dosing system carefully controls the amount of chemicals added to the water based on the chiller's requirements.

Check the pump motor temperature by touching the motor housing.

• Touch the motor housing with your hand to feel for excessive heat

• Use a temperature gun to measure the motor temperature

• Check for any unusual smells or sounds coming from the motor

• Monitor the motor's temperature gauge if available

The AHU belt size can vary depending on the specific model and manufacturer of the air handling unit.

• AHU belt size is typically specified by the manufacturer in the unit's documentation.

• It is important to refer to the AHU's manual or contact the manufacturer for the exact belt size needed.

• AHU belt sizes can range from small belts for residential units to larger belts for commercial or industrial units.

Safety of chiller includes proper installation, regular maintenance, and following safety protocols.

• Proper installation to prevent leaks and malfunctions

• Regular maintenance to ensure efficient and safe operation

• Following safety protocols such as wearing appropriate PPE and avoiding contact with hot surfaces

• Ensuring proper ventilation to prevent overheating

If wbt & dbt are equal, the air is fully saturated and the relative humidity is 100%.

• The air is fully saturated with water vapor.

• The relative humidity is 100%.

• Condensation may occur on surfaces due to the high moisture content in the air.

• This condition is known as the dew point temperature.

Superheating is the process of heating a substance above its boiling point without it changing into a gas.

• Superheating occurs in steam boilers when steam is heated beyond its saturation temperature.

• It increases the energy content of the steam and improves efficiency in power generation.

• Superheating is important in industrial processes where precise temperature control is required.

There are two main types of compressors: positive displacement compressors and dynamic compressors.

• Positive displacement compressors: Reciprocating, rotary screw, rotary vane

• Dynamic compressors: Centrifugal, axial flow

Cooling tower capacity refers to the amount of heat that can be removed from a system by the cooling tower.

• Cooling tower capacity is typically measured in tons of refrigeration or kilowatts.

• It is influenced by factors such as the flow rate of water, the temperature difference between the inlet and outlet water, and the wet bulb temperature.

• Cooling tower capacity can be calculated using the formula: Q = mcΔT, where Q is the heat load, m is the flow rate of water, c is the spec...read more

A VFD (Variable Frequency Drive) controls the speed of an AC motor by varying the frequency and voltage of the power supplied to the motor.

• VFD converts fixed frequency AC power to variable frequency AC power

• It adjusts the motor speed by changing the frequency of the electrical power supplied to the motor

• VFDs are commonly used in HVAC systems, pumps, conveyors, and other industrial applications

The frequency of eddy current test depends on the material being tested and the thickness of the material.

• The frequency can range from a few hundred Hz to several MHz

• Higher frequencies are used for thinner materials and lower frequencies for thicker materials

• The frequency also depends on the type of probe being used

• For example, a probe with a diameter of 1mm may have a frequency of 1MHz, while a probe with a diameter of 10mm may have a frequency of 100kHz

SOP stands for Standard Operating Procedure. Lotto is a game of chance.

• SOP is a set of step-by-step instructions to carry out a specific task or operation.

• It ensures consistency and quality in the output.

• For example, a manufacturing company may have an SOP for assembling a product.

• Lotto is a game of chance where players select a set of numbers and hope to match them with the numbers drawn in a lottery.

• It is a popular form of gambling in many countries.

Glass specifications and concrete quality are crucial for structural integrity.

• Glass specifications include thickness, strength, and type (e.g. tempered, laminated)

• Concrete quality is determined by strength, durability, and workability

• Both materials must meet building codes and standards for safety and performance

• Proper installation and maintenance are also important for long-term performance