Phase 2 Assessment Flashcards
(103 cards)
1
Q
What is 0 Kelvin (absolute zero)?
A
-273 degrees celsius
2
Q
How much does air weigh?
A
1.29 kg/m3
3
Q
What is 100 celsius in Kelvin and Fahrenheit?
A
373K and 212 Fahrenheit
4
Q
What is 0 celsius in Kelvin and Fahrenheit?
A
273 K and 32 Fahrenheit
5
Q
What is -100 celsius in Kelvin and Fahrenheit?
A
173K and -148 Fahrenheit
6
Q
What is -200 celsius in Kelvin and Fahrenheit?
A
73K and -328 Fahrenheit
7
Q
What is -273 celsius in Kelvin and Fahrenheit?
A
0 K and -460 Fahrenheit
8
Q
How much steam is made from 1 litre of water? (m3)
A
1600
9
Q
What is sublimation?
A
When ice is heated so quicly it goes from solid to gas
10
Q
What happens to the boiling point of water if the pressure increase?
A
It increases
11
Q
What is latent heat?
A
Energy required to change the state of a substance
12
Q
What is sensible heat?
A
Energy required to change the temperature of a substance
13
Q
What is conduction?
A
Heat is pulled from high to low temperature
14
Q
What is convection?
A
Hotter molecules rise when they are heater and more dense materials sink
15
Q
What is radiation?
A
Heat is transferred from one body to another via infrared
16
Q
What is the equation for thermal conductivity?
A
area x difference in temperature
17
Q
What is the equation for heat conductivity?
A
thermal conductivity x U value x temperature difference
18
Q
What is power?
A
the rate at which work is done
19
Q
What is the specific heat capacity of water?
A
4.18 J/kg/degrees celcius
20
Q
What is the equation for volume which includes pi?
A
pi x radius2
21
Q
What is the equation for flow rate?
A
area of the pipe x velocity of the liquid
22
Q
What is direct current?
A
Only goes one way like those in a battery
23
Q
What is alternating current?
A
Goes back and forth like those in a mains supply
24
Q
What is a valance electron?
A
Can be lost or gained
25
What is the definition for amps?
rate that electricity flows through an appliance
26
What is the definition of power?
the rate at which electric energy is converted into other forms of energy
27
What is ohms law?
electric current is directly proportional to voltage and inversely proportional to resistance.
28
What is the equation for voltage?
Current x resistance
29
What is the equation for power?
Current x voltage
30
What are the 3 types of earthing supplies?
TN-S(Terra neutral seperate)
TN-C-S(Terra neutral combined)
TT(Terra terra)
31
How do you work out circuit total resistance?
(1/R1) + (1/R2) + (1/R3)
32
What is 1 bar in Psi?
15 Psi
33
What is the maximum flow possible by sucking on the mains?
12 Litres per minute
34
What are the 3 types of water conditioners?
Electrolytic, Electromagnetic, Magnetic
35
What are the 6 types of water filters?
- Activated carbon filter
- Ion exchange
- Sediment filter
- Reverse osmosis
-Distillation
- Disinfection
36
What are 3 advantages of a direct cold water system?
- Cheaper to install
- Mains pressure
- Drinking water at all outlets
37
What are 3 disadvantages of a direct cold water system?
- No water reserve
- Condensation on pipework
- Greater ware on fittings
38
What are 3 advantages of an indirect cold water system?
- Reserve of water
- Chance of backflow is reduced
- Lower chanve of leaks on fittings
39
What are 3 disadvantages of an indirect cold water system?
- Increased cost of the installation
- Lower pressure at outlets
- Risk of frost damage in the loft
40
What is a solenoid valve?
Electro-mechanical device, which controls the flow of water into the cistern
41
What is a transducers?
senses fluctations in pressure and activates or cuts out the pumps
42
What is the maximum chase depth of brick or block wall?
vertical- 1/3 of depth
Horizontal- 1/6 of the depth
43
What makes a hot water cylinder direct?
An immersion heater is used to heat the water inside
44
What makes a hot water cylinder indirect?
The boiler heats water that passes through a coil within the cylinder which heats the water inside indirectly
45
How is a thermal store heated?
Mains water passes through a heat exchanger which is enclosed in a storage cylinder
46
What height should the vent pipe be above the water level in the cistern?
150mm + 40mm for every metre of height in the system
47
What are 3 positives for an open vented hot water system?
- store of water
- low installation cost
- low noise level
48
What are 3 negaitives for an open vented hot water system?
- space needed for storing water
-risk of freezing
- low pressure system
49
What are 3 positives for an unvented hot water system?
- High pressure + flow
- Balanced pressure at all outlets
- No cw storage needed
50
What are 3 negatives for an unvented hot water system?
- High installation cost
- High system noise
- No store of CW
51
What are the 6 types of showers?
- Digital, mixer valve, pumped, bath shower mixer, gravity, cistern fed
52
What are the 3 classes of cylinders and their pressure capabilities?
Class 1 - 3.6 bar or 25m of head
Class 2- 2.2 bar or 15m of head
Class 3- 1.5 bar or 10m of head
53
How does a thermal store work?
Cylinder is filled with primary water and mains water is fed through a coil within the cylinder
54
What is the coefficient of linear expansion for PPP?
0.00018 per metre per degrees celsius
55
What is the coefficient of linear expansion for copper?
0.000016 per metre per degrees celsius
56
How much does water expand by when it freezes?
10%
57
What to consider before installing an unvented cylinder?
- Available pressure and flow
- Route of discharge pipework, termination and pipe sizes
- type of terminal fittings
-cost
58
How long does the hot water draw off pipe need to be (horizontally)?
Min 450mm
59
At what temperature does the temperature relief valve kick in?
90-95 degrees celcius
60
What are the 4 types of float valves (BS1212)?
1- Portsmouth & Croydon
2- Brass Diaphragm type
3- Plastic diaphragm
4- Cistern float valves
61
What is backflow?
Flowing of water in the wrong direction due to loss of pressure in the system
62
What is the purpose of a single check valve?
Protect category 1 water from category 2
63
What is the purpose of a double check valve?
Protects category 1 water from 2&3
64
What is an AUK1 air gap for?
Wc airgap
65
What is an AUK2 air gap for?
Bath and washand basin
66
What is an AUK3 air gap for?
Kitchen sink & bidet
67
What is AA backflow prevention?
Air gap with unrestricted discharge above the spillover level
68
What is AB backflow prevention?
Air gap with a weir overflow (dental surgery)
69
What is AD backflow prevention?
Air gap with a jump jet (washing machine)
70
What is BSEN806 to do with?
Design installation, testing and maintenance of hot and cold water system
71
What is BS8000 to do with?
Requirements for good workmanship within hot and cold water systems
72
What is hydronic heating?
When water is used to transport heat throughout the building
73
What is the purpose of a low loss header?
enables hydraulic separation by providing a separation point between the primary and secondary circuit, or multiple circuits
74
What are some positives of a reverse return system?
Reduces the need for balancing
- used with S+Y plans
- compliant with building regs part L
75
What are some negatives of a reverse return system?
- more expensive and difficult to install
- Careful planning required
76
What are the required pipe distances betweem underfloor heating loops?
150-225mm
77
What are typical temperatures for underfloor heating? (Concrete and timber floor)
Concrete= 40-45 degrees Celsius
Timber= 50-60 degrees Celsius
78
What are the advantages of warm air heating?
- quick heat up times
-no need for fuel supply
- reduced maintenance cost
79
What are the disadvantages of warm air heating?
- Heat unit and duct work is unsightly
- Large space required
Spreads bacteria & dust
80
What are the advantages of district heating?
- Reduced CO2
- No need for fuel supply
- Helps th gov reach green targets
81
What is the disadvantage of district heating?
If the control plant fails all properties are affected
82
What are storage heaters?
Electric heaters that heat up internal ceramic bricks during the night and release during the day
83
What are the advantages of storage heaters?
-Simple installation
-Safe & quiet
- ideal for no fuel supply
84
What are the disadvantages of storage heaters?
-Electricity is more expensive
- Excess heat is wasted
- difficult to control comfortable conditions
85
What are the 4 components for a boiler plus installation (combi)?
-Load compensation
-Smart control
- Flue gas heat recovery
- Weather compensation
86
How do you calculate current (VIR)?
Divide voltage by resistance
87
How do you calculate current (PIE)?
Power divided by potential difference
88
What are some components of a boiler interlock?
Cylinder stat, room stat, motorised valve, boiler stat, flow switch, air pressure switch
89
What are the 5 types of boilers?
-Traditional (non-condensing)
- System boiler
- Combi boiler
- Freestanding
- Wall mounted
90
What are the 4 types of flues for boilers?
- Room sealed
- Flue less
- Open flue
- Fan-assisted
91
What are the advantages of a traditional boiler?
-Long lasting
- Very robust
92
What are the disadvantages of a traditional boiler?
-Heavy
- Noisy
- Not efficient
- Non compliant with part L
93
What are the advantages of a condensing boiler?
-Compliant with part L
- High efficiency
-High flow rate for Hot water
- Low noise pollution
94
What are the disadvantages of a condensing boiler?
- High maintenance
- Possible to freezing
- Placement of condensing pipe could be difficult
95
What are the advantages of a combi boiler?
- Compact size
- Efficient
- Instantaneous hot water
-Cheap installation
96
What are the disadvantages of a combi boiler?
- Bad flow rate at multiple outlets
- No water reserve
- Difficult to work
97
What is a compartment?
Enclosure specifically designed to house a gas appliance
98
What is the correct fall for a condensate pipe?
45mm per metre away from the boiler
99
What are the 3 grades of copper?
R290- Hard copper
R250- Half-hard copper
R220- Soft (microbore)
100
What are the 3 grades of LCS, colour and use?
1. Heavy-Red-Steam fire
2. Medium-Bue-Heating & Oil
3. Light-Brown-Gas
101
What are the 6 stages of filling and venting a Central heating system?
1- Soundness
2- Cold flush
3- Cleanse system
4- Hot flush
5- Fill the system
6- Check the system
102
Installing an air Seperator allows for the coupling of what two pipes?
Cold feed and vent connections
103
What is atmospheric pressure at sea level?
1.01 bar
