© MHG Heating Ltd
27
MHG Heating Ltd, Unit 4 Epsom Downs Metro Centre, Waterfield, Tadworth, Surrey, KT20 5LR
0845 6448802 Telephone. 0845 6448803 Fax. Email
Website www.mhgheating.co.uk
010310 Draft
9.0 Filling The System
The Initial filling of a sealed heating system, and subsequent refilling, must be by a method that has
been approved by the Water Regulation Advisory Scheme (WRAS) for that type of heating system.
i.e. Domestic
(
In-House
)
Fluid
Category
3
(
C-3
)
Non Domestic (Other than
In-House
)
Fluid Category 4 (
C-4
)
For Category 3 systems, the approved method of filling must comprise of the following components in
the arrangement shown;
•
Control Valve incorporating a Double
Check Valve on the Mains Cold Water
pipework.
•
Temporary Connecting Hose, which must
be disconnected after use.
•
Control Valve, on the heating system.
For Category 4 systems, the approved method of filling must comprise of the following components in
the arrangement shown;
•
Control Valve.
•
Strainer.
•
Verifiable Backflow Device with Reduced
Pressure Zone (RPZ Valve)
•
Incorporating a ‘Type BA’ Air Gap.
•
Tundish.
•
Control Valve.
Further more, in accordance with BS 6644: 2005 system with an input greater than 70kW (nett), an
automatic water replenishment unit shall be installed to automatically replenish any lost or
evaporated water.
Please refer to BS 6644: 2005 for allowable water replenishment methods for use with
sealed/pressurized heating systems.
For information on a comprehensive range of pressurization units that comply with current British
Standards and WRAS Regulations, please contact MHG Heating Ltd Sales.
