Sentinel X400 System Restorer 1Ltr Product Code: 89458

1Ltr. Apply to existing systems for the removal of sludge and deposits. Iron oxide is broken down and dispersed through flushing.


  • Removes Sludge
  • Breaks Down Iron Oxide
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Safety Data Sheet
Additional Information
Technical Specification
  • Brand : Sentinel
  • Product Type : System Restorer
  • Volume : 1 Ltr
  • Model No : X400
  • Pack Size : 1
  • Manufacturer Guarantee : 1 Year Guarantee
  • Pieces in Pack/Case : 1
Product Contents
Delivery & Returns


Standard delivery: €15

Free delivery on all orders over €70.00

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€22.45 Incl. 20% VAT

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Sentinel X400 System Restorer 1Ltr is rated 4.4 out of 5 by 13.
Rated 5 out of 5 by from Reliable brand name Sentinel X400 is recommended by Potterton and many other boiler manufacturers, easy to use and suitable for all types of boiler and pipe work.
Date published: 2014-07-23
Rated 5 out of 5 by from Recommended by plumber This sentinel 400 was recommended to me by the heating engineer who had come out to replace a broken boiler pump. I was advised that there was too much rubbish (he didn't actually use that word!) in my heating system. It was simple to administer and I now look forward to it doing its job in sorting out my sludge!
Date published: 2014-05-02
Rated 5 out of 5 by from Give it time Left this product in systen for two weeks and it made a marked improvement to heating system. I gave cool spots in radiators a few taps with rubber mallet to help loosen sludge and after a week they had gone.When I flushed sytem out there was a good amount of black sludge came out. Just give it time.
Date published: 2013-09-29
Rated 5 out of 5 by from De-sludged! We had a noisy boiler, Our plumber fitted a new pump and suggested we de-sludge. I am a bit sceptical about such things but thought I would give it a try and bought two bottles of X400. With trepidation, we drained some water off, poured it in and crossed our fingers. It's 3 weeks since we put it in and the system needs draining down again but it's worked a treat. It took a few days but the boiler is now unbelievably silent so I'll be following up with X100 & X200 to complete the job.
Date published: 2013-04-27
Rated 2 out of 5 by from Did not work for my system Hi I constantly have problems with sludge in my system in spite of using gallons of sentinel products throughout the last few years. I have power flushed the system 4 times in the last three years have fitted at least 4 pumps and as many Mid position valves, changed all the downstairs pipework to plastic the latest sequence of attempts was to power flush over 2 days using sentinel X800. This seemed to work well with the extra push provided by the power flush pump but as soon as I went back to the normal pump I was unable to get a proper flow once again I have now put in some X400 and still so far 3 days in the circulation is no better. So I have no confidence in any of the sentinel products, I always put inhibitor in and have had an Addey Magna clean filter in for all of the 3 years yet I still get pump & valve failures due to sludge. Neil
Date published: 2013-03-09
Rated 5 out of 5 by from Sentinel X400 I purchased this product to disolve a sludged microbore system which could not be powerflushed. I double dosed and found that the system during it's cleansing had already started to perform better.
Date published: 2013-01-24
Rated 5 out of 5 by from Works great for me It must vary according to the kind of water and sediment you have, but in my experience it is fantastic at loosening black iron oxide sludge from old open-vented systems. On one 30-year-old system I drained and gave it plain water flushes and fitted a Magnaclean first, and waited until the water appeared to be clear. I then added X400 and within days was getting enough sludge out to fill several jam-jars. I later converted it to fully-pumped and got a lot more out of the HW circuit that had not been dislodged by the gravity flow. Radiators heated much more quickly and evenly, and the boiler was quieter - unsurprisingly when you see the amount of sludge that came out. The boiler was still bonking due to limescale, and I subsequently added X200 which took some weeks to quieten it and wash away the hard limescale.. The customer who says he got little sludge out must have been lucky enough to have a relatively clean system. You can clean radiators more effectively if you close all but one so all the flow goes through that one to wash away the sediment. Then close that one, and open the next. This might take all day but I think improves the clean. If you have a system filter, keep emptying it at least weekly at first. You will be able to see when there is little new sediment appearing, and reduce the frequency of emptying. Very good price at Screwfix.
Date published: 2012-12-18
Rated 5 out of 5 by from Definitely works given time We have a big 3 storey house with 18 radiators most of which are 20 years old. Simply added 2 containers of this to a partially drained system and allowed to circulate. It took 6 weeks over winter, running the system normally, for a change to be noticed in the poorly performing radiators. Drained the system completely after a few more days, flushed through for half an hour, filled and drained again, before adding 5l antifreeze/inhibitor plus one container of inhibitor and the difference is truly impressive. I have had to rebalance all the radiators since they were simply too hot upstairs and this has allowed the ground floor radiators to benefit from the balance of heat. We need the heating on for less time now and it is quieter and quicker to heat up.
Date published: 2012-03-28
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