Installation & Maintenance Instructions for an unvented
hot water cylinder with internal thermal expansion
Hot Water
Energy
Storage
Unvented Cylinder
SEPT 2018
5
SITING THE UNIT
The unvented cylinder can supply outlets above it or at
some distance from it. Site the unit to minimise “dead leg”
distances, especially to the point of most frequent use.
Outlets above the unvented cylinder will reduce the outlet
pressure available by 0.1 bar for every 1m of height difference.
The unit should be protected from frost. Particular care
is needed if siting in a garage or outbuilding. All exposed
pipework should be insulated. The unvented cylinder must
be installed VERTICALLY on a flat base capable of supporting
the weight of the cylinder when full. The minimum
recommended cupboard size is 650mm wide by 750 deep.
NOTES:
The pressure reducing
valve, non-return valve
and expansion relief valve
are combined together in
the inlet control set.
On 60 – 180 litre sizes there
is no dedicated secondary
return boss and the
secondary return circuit
should be tee’d into the
cold feed pipe just above
the drain elbow.
SCHEMATIC DIAGRAM
Access for maintenance of the valves should be considered.
Consideration should be given to position of discharge
pipes (tundish), drain valves - shall be positioned away from
electrical components.
The immersion heaters are 410
mm long and care should be
taken to ensure that they can be withdrawn for servicing
if required. The discharge pipework from the safety valves
should fall continuously and terminate safely.
IMMERSION
HEATER
COLD
MAIN
ISOLATING
VALVE
PRESSURE
REDUCING
VALVE
NON
RETURN
VALVE
EXPANSION
RELIEF
VALVE
TUNDISH
TEMPERATURE
& PRESSURE
RELIEF VALVE
BALANCED
COLD
CONNECTION
COLD
INLET VIA
DRAIN
NON
RETURN
VALVE
BRONZE
PUMP
SECONDARY RETURN CIRCUIT
( 210, 250 & 300 L SIZES )
DUAL
STAT
2 PORT
VALVE
BOILER
FLOW
BOILER
RETURN
HOT OUTLET