A Quick Guide To Refilling A Heating System

This guide will show you how to re-fill a pressurised heating system that has been drained down.

Follow the instructions or watch the video to discover the best way to fill a pressurised heating system.

How Do I refill My Heating System?

To begin with, you will have to close all of the air vents and drain offs by turning them clockwise.

Fill Pressurised Boiler_1_Close Vents

Before filling up it’s important to add central heating inhibitor.

Do this by simply removing a radiator blank and pouring the inhibitor into the system.

Fill Pressurised Boiler_1_Remove Air Vent
Fill Pressurised Boiler_3_Pour Inhibitor

Doing this will help to prevent corrosion throughout your heating system and reduce the chance of having heating problems in the future.

Follow the inhibitors manufacturing instructions; generally, one tub or bottle will be adequate for up to 10 radiators.

Where Will I Find My Filling Loop?

By your boiler, you should have a filling loop on the pipework.

Fill Pressurised Boiler_4_External Filling Loop

Or you may have an internal filling loop situated at the bottom of your boiler.

Fill Pressurised Boiler_5_Internal Filling Loop

To begin refilling your system, open the filling loop to the downstairs radiators first.

Fill Pressurised Boiler_6_Downstairs Bleed

Once you have done this, you can repeat the process for all of the upstairs radiators too.

Fill Pressurised Boiler_7_Upstairs Bleed

Turn your radiator key anti-clockwise until water begins to trickle out.

Fill Pressurised Boiler_8_Rad bleed to fill

Please note that if you have a towel radiator, be sure to do this last as it is normally the highest point of the heating system.

Fill Pressurised Boiler_9_Towel Rail bleed to fill

Once you have filled all of your radiators, close the filling loop ensuring that the system pressure is around 1-to-1.5 bar. It may help if someone monitors the pressure whilst you are filling up so you don’t over-pressurise the system.

Fill Pressurised Boiler_10_Boiler

After you have re-pressurised the system, you can then turn your boiler back on. Always make sure that all of your radiators are warming up.

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