Ariston 500 STI UK Instructions For Installation Manual - Page 11
Browse online or download pdf Instructions For Installation Manual for Water Heater Ariston 500 STI UK. Ariston 500 STI UK 24 pages. Unvented hot water storage cylinders
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Temperature & pressure
relief valve
F
. 2.9
IG
T
2. Sizing of copper discharge pipe "D2" for common temperature valve outlet sizes.
ABLE
Valve outlet size
G 1/2
G 3/4
G 1
consideration should be given to the installation of an
electronically operated device to war n when discharge takes
place. Note: The discharge will consist of scalding water and
Metal discharge pipe (D1) from
temperature & pressure relief valve.
to tundish.
500mm Max.
300mm
Min.
Metal discharge pipe (D2) from tundish
with continuous fall. See Table 2 and worked
example.
Minimum size of
Minimum size of
discharge pipe D1*
discharge pipe D2*
from tundish
15mm
22mm
28mm
WORKED EXAMPLE
The example below is for a G
discharge pipe (D2) having 4 no. elbows and length of 7m from the tundish to
the point of discharge.
From T
2;
ABLE
Maximum resistance allowed for a straight length of 22mm copper discharge
pipe (D2) from G
for 4 no. 22mm elbows at 0.8m each = 3.2m. Therefore the maximum permitted
length equates to: 5.8m. As 5.8m is less than the actual length of 7m therefore
calculate the next largest size.
Maximum resistance allowed for a straight length of 28mm pipe (D2) from G
temperature & pressure valve equates to: 18m. Subtract the resistance for 4 no.
28mm elbow at 1.0m each = 4m. Therefore the maximum permitted length
equates to: 14m
As the actual length is 7m, a 28mm (D2) copper pipe will be satisfactory.
Tundish
Maximum
resistance allowed,
expressed as a
length of pipe (i.e.
no elbow or bends)
22mm
Up to 9m
28mm
Up to 18m
35mm
Up to 27m
28mm
Up to 9m
35mm
Up to 18m
42mm
Up to 27m
35mm
Up to 9m
42mm
Up to 18m
54mm
Up to 27m
1
/
temperature & pressure relief valve with a
2
1
/
temperature & pressure valve is 9m. Subtract the resistance
2
11
Discharge below
fixed grating.
(see page 10 for
alternative points
of discharge).
Fixed grating
Trapped gulley
Resistance created
by each elbow or
bend
0.8m
1.0m
1.4m
1.0m
1.4m
1.7m
1.4m
1.7m
2.3m
1
/
2