REMEHA 1000 Indirect, Installation Manual

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The secondary return pipe should be in 28mm pipe and incorporate a check valve to prevent backflow.
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A suitable WRAS approved bronze circulation pump will be required.
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On large systems, due to the increase in system water content, it may be necessary to fit an additional expansion vessel to the secondary
circuit. This should be done if the capacity of the secondary circuit exceeds 10 litres.
Pipe capacity (copper):
15mm O.D. = 0.13 l/m (10 litres = 77m)
22mm O.D. = 0.38 l/m (10 litres = 26m)
28mm O.D. = 0.55 l/m (10 litres = 18m)
Note: Plastic pipe capacities may be reduced due to thicker wall sections.
In installations where a secondary circulation is required particular attention should be paid by the installer to maintain the returning water temperature
(guidelines state that a minimum of 55°C return temperature is advisable).
Factors such as, but not limited to, secondary circulation flow rates, minimising heat loss of all secondary circuit pipework and timed operation during
periods of high demand are critical to the correct operation and longevity of the heating element(s) and thermostats.
Secondary circulation is not recommended when using auxiliary immersions on off-peak tariffs where the secondary circulation is not controlled
in
conjunction with the heat source as performance can be affected.
De-stratification kits
The correct size of de-stratification kit must be used with your cylinder to ensure the volume can be circulated in 1 hour. The pump instructions
will need to be reviewed for information on the correct setting. Please follow the installation schematic below for guidance. When the system
circulates needs to be specified by the installer to ensure water is not drawn off during the de-stratification process. If a hot water demand is
required during this period cold water may be discharged from the hot outlet. It is recommended that a check valve be installed before the pump
to stop any risk of cold water draw off through the pump when it is not in use.
For guidance on installation please refer to figure 9.
Discharge
It is a requirement of Building Regulation G3 that any discharge from an unvented system is conveyed to where it is visible, but will not cause
danger to persons in or about the building. The tundish and discharge pipes should be fitted in accordance with the requirements and guidance
notes of Building Regulation G3. The G3 Requirements and Guidance section 3.50 - 3.63 are reproduced in the following sections of this
manual. For discharge pipe arrangements not covered by G3 Guidance advice should be sought from your local Building Control Officer.
Any discharge pipe connected to the pressure relief devices (expansion valve and temperature/pressure relief valve) must be installed in a
continuously downward direction and in a frost free environment.