Discharge Arrangement - Mitsubishi Electric Ecodan HUS210FTC4ST Installation Manual

Discharge Arrangement

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Position the inlet control group so that the discharge from both 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 to, and lower than, the
safety device, with no more than 600mm of pipe between the valve outlet and the tundish.
Any Discharge should be visible at the tundish. The tundish should be located such that any discharge is visible.
In addition, where discharges from safety devices may not be apparent, e.g. people with impaired vision or mobility,
consideration should be given to the installation of a suitable safety device to warn when discharge takes place,
e.g. electronically operated.
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: D2 pipe from tundish is now allowed to be installed in soil stacks within premises. This activity is not
recommended as discharge from T&P may continue for long periods of time. It is the installer's responsibility
to ensure the discharge pipework can support the discharge for prolonged periods. If used follow guidance
on mechanical seal without water trap given in G3 Building Regulations. As discharge can be in excess of
90ºC discharge into plastic pipework is also not recommended
The discharge pipe (D2) from the tundish should:
A) Have a vertical section of pipe at least 300mm long, below the tundish before any elbows or bends
in the pipework.
B) Be installed with a continuous fall of at least 1 in 200 thereafter.
FTC4 Installation Manual
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