21
5.15 P
RESSURE
R
ELIEF
V
ALVE
A Pressure Relief Valve (PRV) is supplied with the system.
The pump group has a dedicated PRV connection point -see fig. 5.15A.
Alternatively the PRV can be fitted to any part of the system using an
appropriate T fitting.
The PRV discharge should be plumbed to a low level and terminated inside
a suitable container to collect any discharged heat transfer fluid. The
discharge and container should be inside the dwelling normally under the
pump group - see figs. 5.1A and 5.15A.
No manual isolation valves are permitted in the pipework to the PRV or in
the PRV discharge pipe.
F
IG
. 5.15
A
P
RESSURE
R
ELIEF
V
ALVE
Pressure Relief Valve
PRV
Discharge
t
h
g
i
e
h
m
e
t
s
y
S
)
s
e
rt
e
m
(
g
n
il
li
f
m
e
t
s
y
S
e
r
u
s
s
e
r
p
)
s
e
rt
e
m
(
l
e
s
s
e
V
n
o
i
s
n
a
p
x
E
f
o
e
r
u
s
s
e
r
p
-
e
r
P
l
e
s
s
e
V
l
5
2
l
e
s
s
e
V
l
5
2
l
e
s
s
e
V
l
5
2
l
e
s
s
e
V
l
5
2
l
e
s
s
e
V
l
5
2
d
r
a
d
n
a
t
s
d
r
a
d
n
a
t
s
d
r
a
d
n
a
t
s
d
r
a
d
n
a
t
s
d
r
a
d
n
a
t
s
l
e
s
s
e
V
l
5
3
l
e
s
s
e
V
l
5
3
l
e
s
s
e
V
l
5
3
l
e
s
s
e
V
l
5
3
l
e
s
s
e
V
l
5
3
l
a
n
o
it
p
o
l
a
n
o
it
p
o
l
a
n
o
it
p
o
l
a
n
o
it
p
o
l
a
n
o
it
p
o
0
1
o
t
3
5
.
1
3
.
1 3
.
1 3
.
1 3
.
1 3
.
1
4
.
1 4
.
1 4
.
1 4
.
1 4
.
1
1
1
6
.
1
4
.
1 4
.
1 4
.
1 4
.
1 4
.
1
5
.
1 5
.
1 5
.
1 5
.
1 5
.
1
2
1
7
.
1
5
.
1 5
.
1 5
.
1 5
.
1 5
.
1
6
.
1 6
.
1 6
.
1 6
.
1 6
.
1
3
1
8
.
1
6
.
1 6
.
1 6
.
1 6
.
1 6
.
1
6
.
1 6
.
1 6
.
1 6
.
1 6
.
1
4
1
9
.
1
7
.
1 7
.
1 7
.
1 7
.
1 7
.
1
7
.
1 7
.
1 7
.
1 7
.
1 7
.
1
5
1
0
.
2
8
.
1 8
.
1 8
.
1 8
.
1 8
.
1
8
.
1 8
.
1 8
.
1 8
.
1 8
.
1
The chart below gives the initial pressure charge that the expansion vessel
will require for a given system height (static system head).
The expansion vessel should be charged to this pressure prior to filling
the system.
The factory set pressure of vessels is 2.5 bar.
Note:
The PR valve is factory set at 6bar.
