HW - controls unvent

The function of control thermostats used in unvented hot water systems is to:

• Regulate the temperature to prevent overheating

• Increase the water pressure

• Filter impurities from the water

• Add minerals to the water

The function of overheat thermostats (thermal cut-out) used in unvented hot water systems is to:

• Prevent overheating by cutting off the power supply when a certain temperature is exceeded.

• Increase the water temperature to improve efficiency.

• Maintain a constant water temperature regardless of usage.

• Provide a backup heating source in case of primary system failure.

The function of temperature relief valves used in unvented hot water systems is to:

• Regulate the water temperature

• Release excess pressure

• Prevent water leakage

• Control water flow

What happens to the boiling point of water as the pressure of the water rises?

• It decreases

• It remains the same

• It rises

Fill in the blank: Water inside the unvented hot water storage vessel is stored above ________ pressure.

• atmospheric

• normal

• standard

• ambient

What is the temperature range for the control stat in an unvented cylinder?

• 60-65°C

• 70-75°C

• 50-55°C

• 80-85°C

What is the function of the temperature relief valve on an unvented cylinder with internal expansion?

• To regulate the temperature of the water

• To release excess pressure and prevent overheating

• To control the flow of water into the cylinder

• To measure the temperature of the water

What is the temperature range set for a control thermostat in a hot water system?

• 30-40°C

• 50-60°C

• 70-80°C

• 90-100°C

Explain how indirectly heated vessels have the thermostat wired to the central heating wiring centre.

• The thermostat is directly connected to the heating element.

• The thermostat is wired through a relay to the central heating wiring centre.

• The thermostat is not connected to the central heating system.

• The thermostat is connected via a wireless module.

What is the secondary function of most temperature/pressure-relief valves?