Worked Example - Dimplex Ec-eau Installation And User Instructions Manual

Table 2: Sizing of copper discharge pipe "D2" for common temperature relief valve outlet sizes
4.4.2

Worked example

This example is for a G½ temperature
relief valve with a discharge pipe (D2)
(as fitted on 125 to 300L cylinders)
having 4 No. 22mm elbows and length
of 7m from the tundish to the point of
discharge.
From Table 2,
resistance allowed
length of 22mm copper discharge pipe
(D2) from a G½ temperature relief
valve is 9.0m. Subtract the resistance
for 4 No. 22mm elbows at 0.8m each
= 3.2m.
the maximum
for a straight
Pre-Installation
Therefore the maximum permitted
length
equates to 5.8m, which is less than
the actual length of 7m, therefore
calculate the next largest size.
Maximum resistance allowed for a
straight length of
discharge pipe (D2)
temperature relief valve is: 18m
Subtract the resistance for 4 No.
28mm elbows 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.
28mm copper
from a G½