Hot water 1

What does WRAS stand for?

• Water Regulations Advisory Scheme.

• Water Resource Allocation System.

• Waste Recycling Advisory Service.

• Water Rights Assessment Society.

What are the two things that WRAS does?

• Publishes the Water Regulations Guides; Lists approved fittings

• Issues building permits; Conducts water quality tests

• Manages water supply; Repairs plumbing systems

• Provides plumbing training; Certifies plumbers

Describe the difference between a centralised and a localised hot water system.

• Centralised: water is heated and/or stored centrally in the building and is distributed from that point to all the hot water outlets. Localised: water is heated and/or stored locally to one specific draw-off point area.

• Centralised: water is heated at each outlet, while localised systems store water in a central tank. Localised: water is distributed from a central point to all outlets.

• Centralised: water is only heated when needed at each tap. Localised: water is always kept hot in a large central tank.

• Centralised: water is heated and stored in each room separately. Localised: water is heated and stored in the basement only.

What gives an open vented system its working pressure?

• The head height of the CWSC.

• The size of the expansion vessel.

• The power of the pump.

• The diameter of the pipework.

Fill in the missing information in the text below. BS6700 states that an open vent must be a minimum of ____ and have no valves in it at all. The hot distribution pipe, as it leaves the hot water cylinder, should ____ slightly and should be a minimum of ____ long before it connects to the vent pipe. The primary function of the vent pipe is to act as a ____.

• 22mm, rise, 450mm, safety device.

• 15mm, fall, 300mm, pressure reducer.

• 28mm, level, 600mm, flow restrictor.

• 10mm, drop, 200mm, temperature sensor.

Describe the difference between a single feed system and a double feed system.

• Single feed: uses a primatic cylinder, relies on an air bubble to separate primary and secondary waters, both filled via a single feed pipe from the CWSC. Double feed: uses an indirect cylinder, primary and secondary waters separated by a coil, primaries filled from F&E, secondaries from CWSC.

• Single feed: uses an indirect cylinder, both primary and secondary waters are filled from F&E. Double feed: uses a primatic cylinder, both waters are filled from CWSC.

• Single feed: uses a coil to separate waters, both filled from F&E. Double feed: uses a primatic cylinder, both filled from CWSC.

• Single feed: uses a direct cylinder, both waters are filled from the mains. Double feed: uses a primatic cylinder, both filled from F&E.

What are the main advantages of an indirect system?

• Part L compliant; Various sizes of cylinders available; The system can be fully pumped

• Requires no maintenance; Only suitable for small properties; Uses only renewable energy

• Directly heats water at the tap; No need for a cylinder; Only works with combi boilers

• No need for insulation; Only available in one size; Not suitable for pumped systems

Which of the following is a key feature of a direct hot water system?

• Water is heated directly within the cylinder by an immersion heater or boiler.

• Water is distributed from a central plant room only.

• Water is always heated by a separate heat exchanger coil.

• Water is only supplied from the mains at high pressure.

According to BS6700, what is the primary reason for ensuring the vent pipe has no valves fitted?

• To increase the flow rate to outlets.

• To reduce heat loss from the system.

• To allow for easy isolation during maintenance.

• To prevent restriction of pressure relief in the event of overheating.

Which component is responsible for separating primary and secondary water in an indirect cylinder?

• The cold water storage cistern.

• The open vent pipe above the cylinder.

• The immersion heater element.

• The heat exchanger coil inside the cylinder.