Technical data

6.0 System Details – page 11
Key
1 Expansion Vessel
2 Primary Heat Exchanger
3 Safety Thermostat
4 CH Thermostat Sensor
5 3 Way valve
6 DHW Plate Heat Exchanger
7 CH Flow Switch
8 Pump
9 Pressure Gauge
10 CH Flow Valve
11 Gas Inlet
12 DHW Mains Inlet
13 DHW Flow Switch
14 CH Return Valve
15 Pressure Relief Valve
16 Filling Loop
17 Flow Regulator
18 Filter
19 Gas Valve
6.8 Domestic Hot Water Circuit
1. All DHW circuits, connections, fittings, etc. should be
fully in accordance with relevant standards and water
supply bye-laws.
2. Your attention is drawn to:
IRN 116 and Byelaw 90 and 91.
Sealed primary circuits and/or secondary hot water
systems shall incorporate a means for accommodating
the thermal expansion of water to prevent any
discharge from the circuit and/or system, except in an
emergency situation.
3. When the system includes any device which prevents
water expanding back towards the supply (check valve,
loose jumpered stopcock, water meter, water treatment
device), then an expansion vessel must be fitted (e.g.
Zilmet 160ml, R½ 15bar).
To comply with Byelaw 91, a check valve must also be
fitted on the supply as shown, to ensure efficient
operation and also to prevent the reverse flow of hot
water into the supply pipe.
4. If the hot water expansion is not provided for, then high
pressures can develop which may result in damage to
fittings and devices on the system.
5. The boiler’s maximum working mains pressure is 10
bar (150 lb/in²), therefore all pipework, connections,
fittings, etc. should be suitable for pressures in excess
of 10 bar. A pressure reducing valve must be fitted for
pressures in excess of 10 bar. The manufacturer of any
outlet fittings, such as a shower valve, may require a
lower maximum pressure. The pressure reduction must
take account of all fittings connected to the DHW
system.
6.9 Showers
1. If a shower control is supplied from the appliance it
should be of the thermostatic or pressure balanced
type. Thermostatic type shower valves provide the best
comfort and guard against water at too high a
temperature. Existing controls may not be suitable -
refer to the shower valve manufacturer.
6.10 Hard Water Areas
1. If the area of the installation is recognised as a HARD
WATER AREA then a suitable device should be fitted
to treat the mains water supply to the boiler.