Flashcards in Hot And Cold Wter Supply Deck (24)
Under normal circumstances at what height does the water in the vent pipe stand?
1/16 of height from the bottom to the water level.
What is the vent pipe sometimes mistakenly known as?
Will the hot water cylinder empty during normal use if the cistern empties of water?
Explain where the direct pipe is on a direct hot water system.
It is 1/16 of the bottom of the cylinder to the cistern water level.
Explain where the cold feed is on a direct hot water system.
It is below the cold distribution pipe.
Why are boilers used on a direct system made from stainless steal or copper?
It is used because it prevents corrosion and discolouration of the water.
Explain the term 1 pipe circulation.
The circulator flow return of hot water takes place in the same pipe due to convection currents.
How is 1 pipe circulation prevented?
It is from the top of the cylinder you run a horizontal pipe from 457mm to the vent pipe.
List 3 functions of the vent pipe.
It maintains atmospheric conditions in pipe work, permits the escape of air and in the event of the water becoming overheard it allow it to discharged over feed cisterns.
How high above the water level should the vent pipe rise before turning back down towards the cistern?
It should be continued over the water level of 1/16 the height of the bottom of the cylinders to the water levels in the cisterns.
Give 2 reasons why the vents should travel up above the water level as I'm question before.
1. Prevents expanding water from pitching into the cistern and gathering air.
2. The vent should be terminate about overflow levels in the cistern and preferably below the flood level.
Where should the vent pipe terminate over the cold water storage cistern?
It must be above the overflow level of the cistern and preferably below the flood levels.
Which water system best supports stratification?
How is stratification prevented?
Define a boiler?
It is made from caste iron, illiumion or copper. If made from caste iron rusting or discolouration of the water does not cause problems because water is never changing.
What is the main advantage of a gas boiler?
It is clean and effective,
What are tempering or mixing/blending valves used for?
Termastatic mixing valves are used to control temperature of water to the tap or shower
Name two places where they must be used.
2. Wash basins.
Give 3 reasons why water should be stored at 65C if it can cause burns.
1. Kills bacteria.
2. Allows a acquit quantity of water.
3. Used in many kitchens.
List 2 ways in which a plumber can help to prevent the possibility of scalding.
1. Thermostatic showers mixers.
2. Cold feeds to cyclinder should be placed at higher levels than cold distribution pipe on storage cisterns.
List 3 places where an airlock may develop on a plumbing system.
1. Sagging pipes
2. When not laid horizontically.
3. Appropriate falls.
How do airlock form In fresh water supplies?
Air bubbles form when water is heated and when water pressure is lowered down
What is the method of heat transfer of transferring hot water from a boilder to a cyclinder above without the aid of a pump?