Plumbing

Partially drain central heating system with radiators closed. drain valve leak.

Anonymous user 03/03/2024 - 3.42 PM

I had my pressure system central heating powerflushed and refilled with inhibitor last week. I have since developed a leak in a drain valve on the system. Guessing the drain valve washer has deteriorated and needs replaced. I spoke to the plumber that completed the powerflush and he has stated that i could close both valves on all the rads, open the motorised valves and just drain whats in the pipes so i don't have to refill with inhibitor. My question is, when i drain the system as mentioned above when i go to refill the system should i refill it with the radiators valves still closed, then open the radiators valves and bleed the radiators? Or drain, replace the drain valve, open the radiator valves and then refill the system and bleed the radiators? Just concerned about airlocking. Thanks