How to add inhibitor to a Central Heating System

salvador2

I need help with this task.

I remember this being done a few years ago and I know need doing it again to replace the inhibitor.

I don't remember if the plumber drained the system (sealed system) before he added the 8 litres through a radiator or maybe he partly drained it.

I know that I have to use the same inhibitor that was used the first time round and that was Fernox MB-1. 8 litres.

So this is what I was thinking to do

1.- drain partly or fully the system
2.- opening the cap where I bleed the radiator and pour in the inhibitor.
3 pressurise the system again
4 bleed the air out
5 top up the pressure


I don't see why I couldn't drain say 10 litres of water then close both valves on the radiator and pour in the inhibitor

Your help is most appreciated.

macman

If it's a sealed system you can simply add it via a rad bleed valve. All the instructions come with the product. No need to drain down.

salvador2

Thank you for the reply. That is good news

I now have a different problem that I need to solve.

My Central Heating was never balanced and for 13 years we have had two rooms where the radiators get hot only when the central heating is at the very top - ie 20 degrees and it only gets warm but hot at over 25 degrees.

I was advised to balance the system but all the shieldvalves are seized. These valves have a plastic know that you turn to open or close. they wont turn at all now. I'm scared to use any tool that might brake the plastic know.

perhaps I should use WD40 or penetrating oil but in all honesty, I have so little faith in those two to help loosen anything in my experience lol - applied heat always works for me but I wound dear use it in this case

I've read that gentle tapping might help.

Cheers

Kiran

Pull the plastic off and there's a metal piece which connects to the plastic cap. You can turn the metal peice with pliers etc.

salvador2

Done that already but thanks all the same.

I was trying to rotate one using a pair of pliers when it broke. I then realised I could do what you just suggested.

Thanks to everybody that helped

macman

If you haven't yet got around to it after 13 years of two cold rooms, then maybe it's time to call a CH engineer in to balance the system?

diywhynot

macman wrote: »

If it's a sealed system you can simply add it via a rad bleed valve. All the instructions come with the product. No need to drain down.

The OP says:

Fernox MB-1. 8 liters.

Does not compute. How do you get 8 litres of fluid into a sealed heating system without removing 8 liters of fluid from the sealed heating system?

O.P.: MB1 is a 'heritage product' and can be replaced by the F1 Liquid, Super Concentrate or Express.

ukmike

Fernox MB-1. 8 liters. Does not compute. How do you get 8 litres of fluid into a sealed heating system without removing 8 liters of fluid from the sealed heating system?

Surly it's 1.8 ltr's, not 8 ltr's?

jayship

Today my plumber put inhibitor in one of my radiators. He emptied the rad in the bathroom and used a cartridge inhibitor to fill in which did not require removing the rad. I paid £10 for a 750ml cartridge.
They also do a spray one which cost £20.

diywhynot

ukmike wrote: »

Surly it's 1.8 ltr's, not 8 ltr's?

No mistake. Fernox MB1. Large system?

southcoastrgi

8 ltrs where do you live buck house ? :eek:

I didn't think you could get MB1 anymore ?

OP X100 1 ltr per 10 rads