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

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.

[Petertronic]

Did the system have inhibitor in it already? Does it stop working after a while? Great video full of good tips, as ever.

[GilesFleming-iysq]

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...

[reinerberridge]

Great video, I have changed radiators in the past and just topped system back up, so I am pretty confident I can follow this walkthrough, saving myself a tidy sum.Thanks again. I had always thought this was a really difficult job to do.

[petef]

Hi, Is that x2 bottles of 1ltr inhibitor for a standard 8 rad system? Thnx

[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!

[daves]

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

[wontfindme]

A job for the pros or an expensive mistake for that miserable know all. 😂

[iansharp]

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

[michaelplays]

Great video, very enjoyable !!! thank you !!!!

[johnfithian-franks]

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.

[MrLear]

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?

[nickayivor]

👍
My Mentor Ultimate Handyman
INTELLECTUAL Ultimate Handyman
From Nick Ayivor from London England UK 🇬🇧 ⏰️ 07:37am Good Morning 🙏 🌄

[Mike_]

Combi boilers are very nasty to the flow and return water in their system