Sentinel - X800 Fast Acting Cleaner 1L, targeted central heating system cleaning inside an hour, restores system efficiency by targeting corrosion debris, ideal for hot and cold systems

My Combi Boiler was Kettleing/Knocking when showering or filling the kitchen sink, I mentioned it when the boiler was serviced and plumber said the plate heat exchanger to heat the water was blocked with limescale and needed replacing, obviously you don't buy a new kettle when it gets bit of limescale on the element! So I opted for this treatment. Best way I could think to add the liquid was the towel heater as it has a nice big fill plug on the top of it and easy access too. I closed both the inlet valves to the towel rail and drained half of the water using the top plug as an tap to control the flow. Once 2 litres out I poured in the treatment refitted the plug and opened the valves, switched on the boiler to circulate the treatment, turned on the hot water tap on to make sure it would clean the plate heat exchanger, 24 hours on there is no knocking or ketteiling, lovely perfect shower at the perfect temperature. Now working out how to drain the treatment out. I will update ASAP. Hope this helps a compitant DIY.. "I can do this" person. Or get a plumber in. Update... Draining the cleaning agent was easier than I thought possible as the towel rail plug is 15mm thread, all I needed to do was close the valves (both in and out) fit a 15mm thru joint with a small piece of 15mm pipe into the plug as mentioned and add a bit of garden hose to go into the loo, the tricky bit was putting the heating valves to fill and opening the towel rail valves so it would flush out the cleaning agent. I did 3 clean flushes till the CH water was clear. Don't forget to do the same process again with the inhibitor to ensure you don't need to do it again soon!

Used this in my heating system after adding new radiator. Left it in for around a couple of weeks during autumn while the heating was only being used a couple of hours in the evening. Flushed the system out, water was a brownish colour, put inhibitor in and refilled it. Found that the heating system is now a lot quieter.

You can't go far wrong when using this product. It does work and fulfils the task it's produced for.

Excellen does a brilliant job

After trying F3 and X400 for a month each and flushing in between decided to give X800 a go at trying to warm up some large double radiators with cold bottoms. The system has 10mm microbore pipes and is pressurised at 1 bar. I was advised by plumber to remove rads and flush them through in the garden, they said powerflush be waste of time too, not enough flow with 10mm pipes. I thought I would give two bottles a go in a 21 radiator system. Well six hours in and the radiators are all toasty warm from tip to toe with the pump running on its fastest setting. Now for the fun of draining and flushing but feels satisfying knowing the X800 has delivered. Brilliant product and ready for putting in X100 inhibitor once system is flushed.

Works well

The effects of this cleaning product inside a heating system is largely unseen. So it’s hard to give a review that’s directly related the products performance. This review is purely based on trusting that the product has done its job effectively.

turns out i didn't really need this product due to other issues so can't relly coment.