More Plumbing Help

Adding Inhibitor To Combi Boiler

Draining system to add Inhibitor

There are a few ways you can add an inhibitor to a Pressurised System (Combi boiler) one is to drain the system and use a normal inhibitor, this can sometimes be poured in by removing a plug on the top of a towel radiator (see picture above) or by injecting it into the radiator with a washing up liquid bottle after removing an air vent plug (see picture below).

Not Draining the system Injecting Through Bleed Valve

There are products that allow you to inject a concentrate or gel into the heating system via a bleed valve without the need to drain the system.
1. First make sure the system is turned off and allow radiators to cool down.
2. Select a radiator if possible one without a thermostatic radiator valve (as you may need shut-off caps to turn off TRVs completely).
3. Shut both of the radiator valves, remove the bleed screw and attach the inhibitor cartridge to the radiator.
4. Open radiator valves, inject concentrate into radiator.
5. Shut radiator valves again, and remove inhibitor cartridge
6. Refit bleed screw, open radiator valves
7. Run heating for 15mins to disperse inhibitor around the system
8.You may need to bleed the radiator (see bleeding)

Not Draining the system Injecting Through Filling Loop

Some also come with an adapter that allows you to inject it through the connector where the filling loop (see pressuring a combi boiler) screws on, this is the easiest way to treat a combi boiler.

1. First make sure the system is turned off and allow radiators to cool down.
2. Turn off tap 1 and remove filling loop (blanking plug)
3. Connect inhibitor cartridge with adapter
4. Turn on tap 1 and inject inhibitor concentrate
5. Turn off tap 1 remove addapter
6. Refit filling loop or blanking plug
7. Run heating for 15mins to disperse inhibitor around the system