R F Blount can supply, install, commission and test Reduced Pressure Zone (RPZ) valves by our RPZ certified engineer.

It is a legal requirement to notifiy the Local Water Authority prior to installation of an RPZ valve, and once installed to have the valve tested annually by an qualified engineer. 

Where vented or unvented closed circuit heating or chilled water cooling systems are required to be rapidly filled for the purpose of flushing or initial filling after installation or after drain-down for major maintenance, it is permissible to use a temporary flexible filling loop connection from a supply pipe with backflow protection.

Backflow protection is required to be by one double check valve installed on the connection point to the supply pipe, with an optional additional double check valve installed on the connection to the closed circuit filling point. The temporary filling loop must be removed after the filling is complete and before the system is pressurised.

Routine topping up of the closed circuit during normal operation must be carried out with the backflow protection required by the Regulations.

Area of Interest: Backflow prevention

Topic: Water heaters

Title: Filling and topping up heating system primary circuits.

Regulation/Byelaw Clause Reference: G15.3 and G24.2

Reference Number:B22       02.33.02

Decision Date: June 2002

Heating system appliances of any size in purely domestic premises, and single appliances or combinations of appliances rated at an output of not more than 45kW (150,000 Btu/hr) in other types of premises (such as small offices), should be regarded as a fluid category three backflow risk.

For such appliances, a temporary filling loop with a double check valve for backflow protection is permitted, the filling loop being disconnected when it is not in use. The double check valve must be installed before the filling loop and remain on supply pipe connection when the loop is disconnected.  

For appliances above this (45Kw) heating output, in other than a house, the filling system would require fluid category four protection. (e.g. An RPZ valve or Mikrofill unit)