Other Tap
Outlets
Expansion | Boiler |
| |
Vessel* |
|
Check
Valve*
6.0System Details
6.8Domestic Hot Water Circuit (Fig. 7)
1.All DHW circuits, connections, fittings, etc. should be fully in accordance with relevant standards and water supply regulations.
2.Your attention is drawn to:
for GB: Guidance G17 to G24 and recommendation R17 to R24 of the Water Regulations Guide.
for IE: the current edition of I.S. 813 “Domestic Gas Installations”.
3. The Water Regulations recommendations for England and |
Wales prohibits backflow from appliances into the |
wholesome water supply due to thermal expansion. |
However this type of instantaneous combination boiler, with |
less than 15 litres of stored capacity, does not require any |
Pressure Reducer 
Valve*
Stop Tap
To Hot
Taps
*See 6.8 for instances when these items may be required
backflow prevention device as any thermal expansion is |
accommodated within the appliance. |
It is possible in certain circumstances that other cold water |
demands (e.g. washing machines, flushing of W.C.s) may |
affect the DHW function of the boiler. In these instances the |
fitting of a backflow prevention device and expansion vessel |
is recommended. |
4. Also if there is an existing check valve, loose jumpered |
Fig. 7
stop cock, water meter or water treatment device already | |
fitted to the wholesome water supply connected to the | |
boiler domestic hot water (DHW) inlet supply then a | |
suitable expansion device may be required. | |
5. The boiler’s maximum working mains pressure is 8 bar, | |
therefore all pipework, connections, fittings, etc. should be | |
suitable for pressures in excess of 8 bar. A pressure reducing | |
valve must be fitted for pressures in excess of 8 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.
6.10Hard 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. Contact your Water Distribution Company for advice on suitable devices.
14© Baxi Heating UK Ltd 2012
