hot water 4-5 revision

1. List as many factors as you can that could cause poor flow rates at the outlets of a hot water system.

• 1) Temperature settings on the thermostat

  2) Limescale build ups

• ·         Filters partly blocked

  ·         Valves partly opened

• ·         Pipework damaged

  ·         High demand period of the day

• ·         Head high too low.

1. What item is used to measure flow rate, and what is flow measured in?

• Flow or weir cup/litres per minute.

• Thermometer, measured in degrees Celsius
• Flow or weir cup, measured in inches

• Scale, measured in pounds

1. If a flow rate was measured at 0.2 litres per second, how many litres per minute would that equate to?

• 0.2 x 90 seconds = 18 litres per minute
• 0.2 x 45 seconds = 9 litres per minute
• 0.2 x 30 seconds = 6 litres per minute
• 0.2 x 60 seconds =12 litres per minute

1. What could be the cause of an isolation valve passing water, even when closed off?

• Limescale build up, debris or an O ring may be damaged.
• Faulty water meter
• Low water pressure
• Corrosion in the pipes

1. What is the most likely cause of a creaking noise under floorboards in a customer’s house when they run hot water to the bath?

• Low Water pressure in the pipes

• The notching of the joist to accommodate the pipes is incorrect.
• Loose floorboards due to poor installation
• Inadequate insulation under the floorboards

1. BS6700 states that the velocity (flow rate) of the hot water should not be too high or it could be heard in the pipework. What is that velocity?

• 5 metres per second
• 2 metres per second
• 10 metres per second
• 3 metres per second

1.  What are common ways to overcome water hammer?

• Increase water pressure
• Install flow restrictor, Change to an equilibrium valve
• Replace the entire plumbing system
• Ignore the issue and hope it goes away on its own

1. What are common ways to overcome water hammer?

• Increase water pressure to counteract the hammer effect
• Inspect clipping distances to make sure they are correct.
• inspect FOV and maybe ball on valve

• inspect FOV and maybe replace tap washer

1. The cylinder thermostat could fail in two positions; what would be the consequences of both?

 

• Fail in open position – no hot water at all.

• Fail in closed position – no hot water at all.
• Fail in open position – hot water temperature would continue to rise.
• Fail in closed position – the hot water temperature would continue to rise.

1. The cylinder thermostat could fail in two positions; what would be the consequences of both?

 

• Fail in open position – no hot water at all.

• Fail in closed position – no hot water at all.
• Fail in open position – hot water temperature would continue to rise.
• Fail in closed position – the hot water temperature would continue to rise.