EHC Fusion E10 Combi Series - Installation - Discharge Arrangement

EHC Fusion E10 Combi – Installation and technical manual Page 12
9. Installation: discharge arrangement
The above diagram is of a typical discharge pipe arrangement.
(extract from Building Regulation G3)
Note: The discharge will consist of scalding water and steam. Asphalt, roofing felt and non-
metallic rainwater goods may be damaged by such discharges.
Note: It is not acceptable to discharge straight into a soil pipe. Position the inlet control
group so that the discharge from both the two safety valves can be joined together via a
15mm end feed Tee. Connect the Tundish and route the discharge pipe.
The discharge pipework must be routed in accordance with Part G3 of schedule 1 of the
Building Regulations.
The information that follows is not exhaustive and if you are in doubt you should seek
advice.
The two safety valves will only discharge water under fault conditions. When operating
normally water will not be discharged. The tundish should be vertical, located in the same
space as the unvented hot water storage system and be fitted as close as possible and
within 500mm of the safety device e.g. the temperature relief valve. The discharge pipe (D2)
from the tundish should terminate in a safe place where there is no risk to persons in the
vicinity of the discharge, be of metal and:
A) Be at least one pipe size larger than the nominal outlet size of the safety device unless its
total equivalent hydraulic resistance exceeds that of a straight pipe 9m long i.e. discharge
pipes between 9m and 18m equivalent resistance length should be at least two sizes larger
than the the nominal outlet size of the safety device, between 18 and 27m at least 3 sizes
larger, and so on. Bends must be taken into account in calculating the flow resistance. Refer
to diagram 1, Table 1 and the worked example. An alternative approach for sizing discharge
pipes would be to follow BS6700 Specification for design installation, testing and
maintenance of services supplying water for domestic use within buildings and their
curtilages.
B) Have a vertical section of pipe at least 300mm long, below the tundish before any elbows or
bends in the pipework.