Pressure Relief Discharge; Pressure Relief Pipe Work - Worcester GR8700iW 35 C Installation And Maintenance Instructions Manual

Open drain or gully with external air break
 Figure 34
Where the pipe terminates over an open drain or gully and there is a risk
of ground flooding, then the additional requirement below is
recommended:
• An air break should be installed in the external pipe work as shown to
avoid an airlock during ground flooding/adverse weather conditions
which could prevent the condensate from discharging.
1
8
12
Fig. 34 Disposal to open drain or gully with air break
[1] Condensate discharge from appliance
[8] Pipe work transition
[9] Insulate and increase pipe size
[11] External air break
[12] Air gap (minimum 10mm)
Condensate soak away considerations
Before deciding to use a purpose-made soak away the history of the
locality and the ability of the surrounding area to disperse the
condensate should be taken into account, e.g. areas prone to flooding
and ground with a high clay content can result in an increased risk of
freezing causing the condensate pipe to become blocked with ice and
the boiler to shut down,
Although it is possible to increase the size of the soak away and the area
with limestone chippings in clay soil areas, if the clay content is high and
prevents effective dispersal of the condensate then a soak away may not
be a suitable means of condensate disposal and an alternative method
should be used.
Condensate soak away with external air break
 Figure 35
• Refer to following example to dispose of condensate to a soak away.
• The condensate soak away must be sited at least 500mm away from
building footings.
• The condensate drainage pipe may be run above or below the ground
to the soak away. The following example shows drainage pipe run
above ground.
• The soak away must use a minimum of a 100mm Ø plastic tube with
two rows of three 12mm holes on 25mm centres and 50mm from the
bottom of the tube. The holes must face away from the house.
• The tube must be surrounded by at least 100mm of limestone
chippings to a depth of 400mm.
• An air break must be installed in the external pipe work as shown to
avoid an airlock during ground flooding/adverse weather conditions
which could prevent the condensate from discharging.
Minimum hole size for the condensate soak away must be 400mm deep
by Ø 300mm.
Greenstar 8000 Style – 6720883864 (2019/02)
9
11
10mm min.
9
25mm min.
1
8
12
15
16
19
Fig. 35 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.
Pre-Installation
400mm min.
25mm min.
500mm min.
9
11
10mm min.
9
15
16
17
18
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