Fernox F1 Express Central Heating Inhibitor & Protector 265ml

I used the filling loop method and was very impressed. It was quick and easy to do. No need to drop system pressure which is nice. You'll tell when the can is empty as it goes cold, and light, obviously. Just be aware that when you remove the can from the filling loop you might have a small amount of pressure that can spirt a bit of the liquid. Maybe a rag over the top as you remove it would do.

Amazon urged me to review so here goes This kind of product works in the background so its difficult to say how well it works I can only say the water in my rads stays clean and I have never had any blockage etc. As far as I know Fernox is the premium product and you can get cheaper but for the number of times you buy it (once a year) I buy the best.

Enough options to suit a lot of different fittings and very easy to use

great price delivery and works. i’ve used this for years and insert it via a filling loop which is quick and mess free. keeps the boiler working nicely.

I ordered this after a boiler service. I watched the manufacturer video and it looked straight forward. Product arrived quickly and when I went to use it the cold water loop connection was too large and thus would not work. I had to return and as it's not direct from Amazon I had to stand the return costs if £2.99. Not very impressed so check your connection sizes.

I've always used this, so easy to apply into system and keeps clean and quiet. May not be cheapest on market but worth every penny

The nozzle is weak ,(broken twice ).

did what it says it does