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How do I repressurise my Greenstar Highflow boiler?

How to repressurise your Greenstar Highflow boiler using a filling link



These repressurisation instructions apply to the following boilers only:

  • Greenstar Highflow 440
  • Greenstar Highflow 440CDi
  • Greenstar Highflow 550CDi

IMPORTANT: We recommend you read these instructions prior to repressurising your heating system

1) Ensure the power to the boiler is turned off and that the heating system is cool.

2) Remove the front panel of the boiler to access the filling link.

Image of How to remove Highflow boiler front panel

3) Locate the filling link. These are located in the bottom left hand side of the boiler as seen below.

Image of Greenstar Highflow filling link

Note: normally, when the filling link is not being used, the connection hose should be disconnected from the bottom pipe. The bottom pipe should have its protective cap fitted.

4) Prepare the filling link for use by ensuring the isolation valves are closed. Remove the protective cover on the bottom pipe. This is shown in the photograph below.

Image of Greenstar Highflow boiler link with cover removed

5) Attach the bottom of the connection hose to the bottom pipe and make sure the connections at both ends are tight.

6) Fill the heating system. To allow water into the system open the two valves at either end of the filling link hose. Open one of the valves fully but to control the flow of water into the system open or shut the second valve gradually.

Image of Greenstar Highflow boiler with isolators open

7) Repressurise the heating system to between 1 and 1.5 bar on the boiler’s pressure gauge. When the pressure has reached between 1 and 1.5 bar, fully close both of the isolation valves.

  • On the Greenstar Highflow 440 the pressure gauge is just above the filling loop.
Image of Greenstar Highflow 440 boiler pressure gauge
  • On the Greenstar Highflow 440/550CDi the pressure gauge is on the boiler’s control panel
Image of Greenstar Highflow CDi pressure gauge

8) Close the isolation valves and then disconnect the filling link flexible hose from it’s bottom connection. Refit the protective cover to the end of the filling link’s bottom pipe.

9) Replace the front cover back onto the boiler.

The repressurisation process may need to be repeated if you bleed the radiators.

For more information on how to repressurise your heating system:


Return to Boiler repressurisation

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