HIP Magazine – Summer Issue 2016- Answer Sheet
PAGE 44
Identify the parts
1
©HIPMagazine
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
2
Name the component or pipe identification
6 Bar pressure relief
Composite valve
Pressure gauge central heating
3bar pressure relief valve for the heating
Expansion vessel for the domestic hot water
Temperature and pressure relief
Cold feed to showers
Connection for hot water secondary return
Manual air vent
Central heating zone valve
D1 pipe
Central heating flow
Differential by-pass
Tundish
Central heating flow
Filling loop
Combined cylinder and high limit thermostat
D2 pipe
Primary flow from boiler
Zone valve for hot water
©HIPMagazine
Page 46
Keeping the dinner warm
B
A
The above photo is a cooker burner, taken out and mounted for
demonstration.
What component is labelled A?
Flame supervision device
What component is labelled B?
Ignition electrode
3
©HIPMagazine
What component is this?
Gas by-pass
If the flame remains on low during initial light up and does
not go to high flame, what is the most likely cause?
Flame supervision device faulty, damaged phial, Phial not in flame
Every time the oven reaches temperature the burner flame
extinguishes, what is the most likely fault?
By-pass blocked, prevent burner remaining on low flame when
reached temperature
When servicing a cooker you discover one of the hot plate
burner is showing signs of incomplete combustion, would
you
o Inform the customer and tell them not to use that particular
hot plate ring.
o Inform the customer and with their permission,
disconnect the appliance and issue an ID.
o Inform the customer and with their permission, isolate the
appliance and issue an AR.
o Don’t worry about it, it’s not caused any harm before.
You have been asked to install an oven in a room of 8m3,
there is a door to outside fitted in the same room, do you
need ventilation?
o Yes
o No
4
©HIPMagazine
Page 48
Hot water and supply systems
G3 Hot water supply and systems
Sizing of copper discharges pipe D2 for common temperature relief valve
outlet sizes
Valve outlet
Minimum
Minimum
Maximum
Resistance
size
size of
size of
resistance
created by
discharge
discharge
allowed,
each elbow
pipe D1
pipe D2 from expressed as or bend
tundish
a length of
straight pipe
(ie no elbows
or bends)
G 1/2
15mm
22mm
Up to 9m
0.8m
28mm
Up to 18m
1.0m
35mm
Up to 27m
1.4m
G3/4
22mm
28mm
Up to 9m
1.0m
35mm
Up to 18m
1.4m
42mm
Up to 27m
1.7m
G1
28mm
35mm
Up to 9m
1.4m
42mm
Up to 18m
1.7m
54mm
Up to 27m
2.3m
The above table is based on copper tube
Answer the question below based on the table above:
1. The length of D2 pipework required from the G1/2 outlet valve is
6m; there are 4 bends on the pipe, what size D2 pipe do you use?
Answer 6m pipe +
4x 0.8 resistance of bends= 3.2m
6m+3.2m= 9.2m
22mm will only be sufficient up to 9m therefore 28mm D2 pipe will be
required
2. You have been asked to check if the existing D2 pipe meets the G3
regulations. From the G1 valve outlet a 22mm pipe has been
installed to a tundish. From the tundish the pipe runs to outside and
terminates pointing down 95mm from the ground and is protected
with a guard. The D2 pipe is 22mm and is 4m long with 5 bends.
Explain your answer.
5
©HIPMagazine
Answer D1, 22mm is less than the minimum size required for a G1 valve
outlet size
3. From a G1/2 valve outlet a 28mm D2 pipe discharges outside, the
pipe run is 6m in length and consists of 4 bends is this installation
acceptable?
Answer Yes
4. Calculate the D2 pipe size required for an installation consisting of a
G1/2 pressure relief valve 12m of pipe with 4 bends
Answer 12m pipe
4x1m (bend resistance) =4m
4+12=16m total pipe length, a 28mm D2 pipe would be required
Page 50
Test your knowledge with the unvented test
Name the 3 building regulations un-vented hot water cylinders are subject
to?
G3 of the building regulations
Part L
Water supply(water fittings) regulation 1999
•
•
•
When linking an unvented boiler to a heat sources, which fuel should not
be used?
o
o
o
o
Electricity
Gas
Oil
Solid fuel
When choosing or replacing an immersion heater for an unvented cylinder
it must comply to BS EN 60335-2-73 and contain a;
6
©HIPMagazine
o
o
o
o
Bi metallic strip
User thermostat and non-resetting thermal cut out (G3 3.29)
User thermostat and self-resetting thermal cut out
Night switch for economy 7
An unvented storage cylinder must never exceed what temperature
o 60 degrees
o 85 degrees
o 100 degrees
o 95 degrees
o
The discharge pipe D1 should be;
o At least the same size as the temperature relief valve (G3
3.51)
o One size larger than the temperature relief valve
o One size less than the temperature relief valve
o The same size as D2 pipe
The maximum length of pipe pipe between the temperature/pressure
relief and the tundish is;
o 500mm
o 300mm
o 600mm (G3 3.54)
o 700mm
The vertical section of pipe below a tundish before any bend or elbow
should be
o 500mm
o 600mm
o 300mm G3 3.56
o 1000mm
D2 pipe should have a continuous fall of at least;
o 1 in 300
o 1 in 200 G3 3.56 b
o 1 in 500
o 1 in 20
Where a single common discharge pipe serves more than one system it
should be at least
o The same size as the largest D2 pipe
o One size larger than the largest D2 pipe G3 3.59
o You cannot have a common discharge pipe
o Two sizes larger than the largest discharge pipe
7
©HIPMagazine
When connecting a discharge pipe to a soil stack, the branch must have;
o
o
o
o
An independent branch pipe to the soil stack G3 3.60
You can use the same branch pipe from another sanitary appliance
You can fit the D2 pipe to a washing machine stand pipe
Only metal pipes can be used
Termination of the discharge pipe needs to be considered to prevent risk
to persons in the vicinity; an appropriate discharge point would be;
o A trapped gully with the end of the pipe below a fixed grating and
above the water seal
o Downward facing low level discharge 100mm above ground with a
wire cage or guard to prevent contact
o A high level discharge into a metal hopper and metal down pipe.
o All the above G3 3.62
To prevent scalding the hot supply to a bath should be limited by a
blending valve to a maximum temperature of:
o
o
o
o
44 degrees
43 degrees
48 degrees G3 3.65
60 degrees
When commission is carried out by a person registered with a competent
person scheme he must give notice to the Building Control Bodies (BCB)
within
o
o
o
o
7 days
10 days
30 days G3 3.78
3 months
What is the recommended cold water pipe size for an unvented cylinder?
o
o
o
o
22mm
35mm
15mm
28mm
What is the recommended minimum flow rate required for an unvented
cylinder?
8
©HIPMagazine
o
o
o
o
10 litres per minute
15 litres per minute
20 litres per minute
25 litres per minute
What is the resistance created by a 22mm elbow on a discharge pipe D2
in metres?
o
o
o
o
0.5m
0.8m G3 Table 1
1m
1.5m
Water discharges continually from the expansion relief valve every time
the cylinder is heated, what could be the possible cause?
o
o
o
o
9
Faulty expansion relief valve
Faulty temperature relief valve
Faulty pressure reducing valve
Faulty Expansion vessel
©HIPMagazine
Page 52
Waste pipe dilemmas
What is the maximum length of a 32mm unventilated branch pipe you can
install?
1.7m Diagram 3 Document H of the building regulations
How many appliances can you connect to a 32mm branch pipe?
3 appliances, Table 2 Document H of the building regulations
What is the minimum depth of trap seal on a wash hand basin connected
to a primary ventilated stack?
75mm Table 1 Document H of the building regulations
10
©HIPMagazine
What type of traps are installed on the wash hand basins above?
Bottle traps
If a bath or shower waste is discharged directly into a gully, what
measurement in millimetres can the trap seal be reduced too?
38mm, Table 1 additional information, Document H building
regulations.
On a two store property what is the minimum distance the lowest branch
can be from the invert of the drain.
o
o
o
o
300mm
500mm
450mm (Diagram 2 Doc H)
1000mm
The gradient on a 32mm pipe is 40mm per metre, what is the maximum
distance you can install this pipe without ventilation.
o
o
o
o
1.7m
1.1m (Table 2 Doc H)
0.7m
2m
The minimum radius of the bend at the foot of the stack should be
o
o
o
o
200mm
100mm
150mm
250mm
(1.26 Doc H)
Ventilating pipes within 3m of an openable window should terminate a
minimum of how high above the window?
o
o
o
o
11
600mm
1000mm
900mm (Diagram 6 Doc H)
300mm
©HIPMagazine