Installation - General - Heatrae Sadia Megalife 100E Installation Manual

3: Installation - General

3.1 Pipe Fittings
All pipe connections to the Megalife are made via 22mm compression fittings directly to the unit (nuts and olives
supplied). The fittings are also threaded 3/4" BSP male parallel should threaded connections be required.
3.2 Cold Water Supply
A 22mm cold water supply is recommended from the cold water feed cistern. No other connection should be taken
from this supply. A servicing valve or stop valve with a fixed washer plate should be incorpoarted in a convenient
and accessible position in the cold feed pipe. The cold feed pipe should be connected to the heater connection
marked with a BLUE collar.
3.3 Drain Tap
A suitable draining tap should be installed at the lowest point of the cold feed pipe between the cold water service
valve and the heater to facilitate draining the heater.
3.4 Outlet Pipework
The outlet pipework should be connected to the heater connection marked with a RED collar in the centre of the
top cover. The vent pipe must be teed into the outlet pipe (see section 3.5 below). Outlets above the heater can be
teed off the vent pipe. Ideally the pipework from the heater to the outlet fittings should be in 22mm pipe with short
runs of 15mm pipe to the terminal fittings. Pipe sizes may vary due to system design.
3.5 Vent Pipe
A vent pipe MUST be connected to the outlet of the heater.
The vent pipe must rise continuously and be arranged to discharge into the cold water storage cistern.
The vent pipe must have a minimum bore diameter of 19mm.
No valves should be fitted to the vent pipe. It is not acceptable to replace the vent pipe with a pressure relief
device.
The hot water distributing pipes can be teed off the vent pipe. If fitting a shower booster pump particular attention
should be made to the manufacturer's instructions regarding the positioning of the hot water tapping to prevent
air entrainment via the vent pipe.
3.6 Secondary Circulation
If secondary circulation is required it is recommended that it be connected to the Megalife cylinder as shown in Fig.
07, page 11. A 1/2" BSP female threaded boss is provided (supplied blanked with a 1/2" BSP plug) for the connection
of a secondary circulation return pipe.
The secondary return pipe should be in 15mm pipe and incorporate a check valve to prevent backflow. A suitable
WRAS approved bronze circulation pump will be required.
In direct electric 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 for direct electric units using off-peak tariffs where the secondary circulation
is not controlled in conjunction with the heat source as performance can be affected.
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