Table of Contents
Advertisement
1
8
12
15
16
19
Fig. 37 Disposal to soak-away
[1]
Condensate discharge from appliance
[8]
Pipe work transition
[9]
Insulate and increase pipe size
[11] External air break
[12] Air gap (minimum 10mm)
[15] 100mm minimum Ø plastic pipe
[16] Drainage holes
[17] Limestone chippings
[18] Bottom of sealed tube
[19] Increase size of soak away size and the area with limestone
chippings if in clay soil area.
Not recommended for high clay soil areas.
4.6
Pressure relief discharge
4.6.1
Pressure relief pipe work
CAUTION:
Scalding risk from hot water or steam!
▶ The pressure relief valve (PRV) is an appliance safety device and may
discharge hot water or steam when activated.
▶ The outlet pipe should be sited in such a way that it does not cause a
hazard or an obstruction when discharging, for example above a
window, entrance door or other public access way.
• The pressure relief discharge pipe [1 or 3] should be run in at least
15mm diameter copper pipe or pipe made of a material that will
withstand PRV discharge temperatures and pressures and which
complies with BS 5254 or BS EN 1451.
• Plastic pipe work must be properly supported with a maximum of
300mm between supports to prevent sagging and run downwards
away from the appliance.
• The pressure relief should discharge away from any electrical or other
hazard, preferably to an external drain or soak-away.
• The pipe [1 or 3] should be finished with a partial bend, near the
outlet to face the external wall (as shown) to help prevent freezing.
Greenstar 8000 Life – 6720883858 (2019/02)
400mm min.
25mm min.
500mm min.
9
11
10mm min.
9
15
16
17
18
0010012788-002
• In all normal circumstances a PRV discharge pipe installation as
described above is suffice to meet all but the most exceptional
circumstances.
– Where the PRV discharge pipe could be susceptible to damage,
vandalism, freezing etc that could cause either a blockage or
restriction in the ability to discharge safely then a tundish should
be considered. The tundish should be sited in a position where
damage to the property or occupants cannot occur from any
spillage or discharge.
1
2
3
4
Fig. 38 Pressure relief pipe work
[1]
Discharge pipe (turned back onto external wall example)
[2]
Outside wall
[3]
Discharge pipe (into drain or gully example)
[4]
External drain
4.6.2
Alternative PRV connections - Combined PRV/condensate
The PRV or a combined PRV/ condensate discharge can be connected
into a suitable internal waste system, the installer must ensure that all
the pipe work, including the waste pipe, is capable of withstanding PRV
temperatures and pressures.
Connection to a waste water pipe is possible by using either:
• A shielded tundish with non-return valve can be used to discharge
upstream of a trap (there must not be a trap directly in the PRV
discharge pipe without a tundish.
• A PRV can discharge directly into a suitable waste pipe downstream
of a trap. Connections must be on top of the pipe to ensure they do
not block. A Hotun (or similar) can be fitted for visual indication if
desired but is not necessary.
The guidance of BS 6798 sections 6.3.5 and 6.4.3.2a must be followed.
Pre-Installation
1
2
2
3
4
27
Advertisement
Table of Contents
