GMJ 6035 Hot water worksheet 4 - maintenance

Temperature settings on the thermostats

Lime scale build ups

Filters partly blocked

Valves partly opened

Pipework damaged

High demand period of the day

Head high too low

These factors could cause what?

• poor flow rates at the outlets of a hot water system.

• Crossflow in a cistern

• pipework to squeak where it passes through joists

• leaks.

What item is used to measure flow rate?

• A tyne cup

• a tees gauge

• a weir cup

• a pressure gauge

What is flow rate measure in?

• Litres per minute

• gallons per hour

• pints per session

• pounds per square inch

If a flow rate was measured at 0.2litres per second. How many litres per minute is that?

• 8

• 10

• 12

• 14

What would not be the cause of an isolation valve passing water even when closed off?

• Lime scale build up

• debris

• reversed flow

• an ‘O’ ring may be damaged

The most likely cause of a creaking noise, under the floorboards in a customer’s house, when they run hot water to the bath, is:

• joiner has used the wrong type or size screw to fasten the floor boards down

• there is a leak on the hot water pipework

• there is a leek on the hot water pipework

• the notching of the joists for the hot water pipework is incorrect/too tight

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

• 3 metres per second

• 3 litres per minute

• 3 pounds per square inch

• 3 degrees per inch

These are all common ways to resolve what issue?

Inspect FOV and maybe replace tap washer

Install flow restrictor

Change to an equilibrium valve

Inspect clipping distances to make sure they are correct

• a leaky tap spindle

• water hammer

• legionella build up

• unpaid invoice

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 closed position: The hot water temperature would continue to rise

• Fail in open position: The hot water temperature would continue to rise

What would be the result of pipework being installed like the diagram?

• Airlock: Intermittent water supply at an outlet

• difficult to fit lagging/insulation

• Airlock: Possible no water supply at an outlet

• easier to hang your manometer on the pipework