How to drain down a central heating system | chemical flush | add inhibitor

Ultimate Handyman
Ultimate Handyman
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Published 2023-02-18
In this video we are draining down a sealed central heating system, which is often found with combination boilers. The water in this system is filthy and needed replacing as soon as possible. It’s critical that the water in the central heating system is kept clean and free from iron oxide/rust/corrosion or limescale, as these things can cause severe damage to the system and the boiler. To do a job like this, it is going to take several hours, so it’s best to have everything ready in advance and be prepared to spend the whole day doing this job.

Sentinel X 800 was used as a chemical flush for the system, because the original water was completely black (it looked like used engine oil). This was left in the system for 1 hour, with the central heating switched on. This was then drained out, and the system was re-filled again, this time a central heating inhibitor, sentinel X100 was added to the system.
All Comments (20)
  • @GilesFleming-iy1sq
    Thank you for this video - when I drilled through a central heating pipe, it helped me through the process of draining the system, & saved me from a very expensive mess...
  • @DjGiluk
    Excellent video, thanks mate πŸ‘πŸ»πŸ‘πŸ»
  • @Pete.Ty1
    πŸ‘πŸ‘πŸ‘Thank you
  • @daves4026
    Great video. I would also suggest you look at stopcore which I use now as they prevent the galvanic reaction, which the magnatec simply collects
  • @Petertronic
    Did the system have inhibitor in it already? Does it stop working after a while? Great video full of good tips, as ever.
  • @stiiffyrabbit
    i subscribed! My boiler has a radiator warning light - it won't fire the rads up - a DHW thermistor error, so i'm told. i have the inhibitor but, the problem of sludge/sediment remains, at least, something is blocking something! before i buy cleanser, do i need sludge removal too? is there a procedure for it? thanks, in advance.
  • @npatrcevic
    Have you ever had bad experiences using the system cleaners? I heard stories of boilers and radiators being eaten up by the acid and starting to leak. I'm going to expand my own system this spring/summer so sharing any bad experiences would be welcome. Great video, as always, thank you!
  • @petef7323
    Hi, Is that x2 bottles of 1ltr inhibitor for a standard 8 rad system? Thnx
  • @iansharp0306
    Hi, does your procedure remove all the cleaner from the system? I was going to do exactly the same as you, but have been advised that some cleaner would still be in the system and can cause problems/damage to system. Would it be ok to add cleaner, run for a few days, drain down, refill and drain again, then fill and add inhibitor? Thanks for your videos, they have helped me loads
  • @MrLear1976
    Quick question. My central heating is on a new build. All 4 downstairs ones are fed from pipes down from the ceiling. Does this mean after draining all of the upstairs from a downstairs I’ll need to drain the other 3 as they’ll still hold water due to the up pipes from each one?
  • @johnfithian-franks8276
    Hi, my system is a direct boiler system without a header tank their has be a slow leak that I have now sorted but I notice the flexible pipe had a small hole so I am unable le to refill until I replace the hose. Is it save to remove the hose and what size are the two nuts on the pipe.
  • @Mike_5
    Combi boilers are very nasty to the flow and return water in their system
  • @wontfindme1289
    A job for the pros or an expensive mistake for that miserable know all. πŸ˜‚
  • @nickayivor8432
    πŸ‘ My Mentor Ultimate Handyman INTELLECTUAL Ultimate Handyman From Nick Ayivor from London England UK πŸ‡¬πŸ‡§ ⏰️ 07:37am Good Morning πŸ™ πŸŒ„