How to add chemicals?

[jgarcia]

Just wondering what the easiest way is to add chemicals (e.g. inhibitors) to a closed CH system?

1. Inject into radiator valve with mastic gun (e.g. for Fernox F1)
or
2. Use a magnaclean
or
3. Use the towel rail in the bathroom

Sorry if its a silly question - I'm new to all of this.
garcia.

 

[Softus]

Towel rail vent is usually the easiest, but you still need to drain (or suck) about 300ml of water out after depressurising.