"Faced with having to renew almost blocked pipes on an oldish and awkward system, this product worked its magic very quickly, thoroughly cleaning out the sludge from the pipes. Before that some of the radiators had stopped working. Would recommend fitting a magnetic filter as well."
"X800 has been cleaning whether others have failed. Reliably removing sludge flake from the heat exchanger when added to the system despite power flushing two years ago. Have drained the system and tried other products since but this one is the best. Works when hot or cold, and bubbles away so you'll need to bleed the highest radiator fairly frequently, but well worth it. It even protects the system from rust whilst its in there so you can leave it in for longer."
"Was told by scottish power boiler care my plate heat exchanger was choked and I'd need a power flush as I was having issues with my hot water on a back boiler. Wasn't entirely convinced so decided to try this. Put a bottle into my system and ran it for an hour, let cool for 30mins, ran for an hour and did this three times. Flushed the system through for about 90 mins afterwards. Re filled and added the sentinel inhibitor hey presto boiler working again with scalding hot water and I'd say it's even a bit quieter now"
"Excellent quality product, works very well when power flushing or with the sentinel eliminator filter to restore boiler & heating system to efficient working order. personally I wont use any other product."
"Was having problems with poor hot water output on our combi boiler - it would take a good couple of minutes after turning the taps on for the water to get fully hot, and after a further minute or two the boiler often shut down and the water ran cold again.
A bit of online research led me to suspect that the cause was likely to be a fairly common problem:- Sludge/magnetite in the CH system blocking the plate heat exchanger from transferring heat efficiently to the DHW.
In an attempt to avoid the ~£500 cost of a professional powerflush (plus the possibility of having to have the plate heat ex cleaned or replaced by an engineer) I thought I'd try putting a litre of this in the system in the hope it would flush enough crud out to get us back up and running. Worth a punt, I thought...
Well, it worked better than I could have hoped! Added the X800 via a radiator, ran the heating for a few hours to get it well circulated, then ran a hot tap for 10 minutes to ensure the plate heat exchanger got a good blast. The problems cleared up pretty much as soon as I'd done this, but I left the X800 in for a few days before flushing thoroughly and the boiler performance gradually improved further over this period.
After flushing, refilled the system and added inhibitor and it's been great since. Saved me the not inconsiderable cost of a powerflush, so am I pretty delighted!"
"I had a couple of blocked radiators in my system, and decided to give the x800 a try as it was favourably reviewed by others. I added 1 litre to my header tank and set the system running. Within an hour or so the system had completely cleared and was working perfectly. Well pleased with the results, and would recommend it."
"Fantastic product, I had 9 radiator blocked out of 17, so after rinsing all of them with the hose pipe in the garden the system was still not working (we have a very old system with micro pipe 8mm) i put 1 container split in 3 radiators and the other one in the tank before filling the system then nothing happenned but on the 6th day the system imbloked its self and now 16 out of the 17 are working and to be fare the last one need surgery !!! and replacement of the pipes has it did not work for 6 years. so I only can recommend the stuff !!! 1 container will treat an average of 9 radiator."
"After replacing my Pump, it shifted some muck around the system. After weeks of pops, squeeks and other terrible noises I decided that a noisy boiler was not a good morning alarm clock to have. At my local Screwfix I purchased 2 bottles of X800, X100 and X200. Many of my radiators are doubles, so needed a good dose. Drained my system and re-filled adding the X800. Left it in on a high pump speed for 7 days. Drained and flushed with water 3 times, untill perfectly clear. Finally re-filled adding X100 and X200. My Ideal condensing boiler is now so quiet I have to keep checking it's on, and I am now sleeping great, no rude alarm clock. Thank you Screwfix, thank you Sentinel! Peace at last.
"I added 1 litre of x800 through a downstairs radiator and left it circulating in the central heating system for 24 hours. The water that came out of the system was very brown indeed. I flushed the system and then added a couple of litres of x100. The result ..... I can hardly hear the boiler now !! The noise was previously very loud with an associated whistling suggesting that the system could not remove the heat generated by the boiler fast enough. Not a problem now."
"I used the X800 without a power flushing machine and it worked wonders, clearing a problem blockage in a domestic heating system in just a day. I left the X800 in for some days with no ill effect before flushing and using X100 to protect. Superb product."
"Cut a long story short, my heating system needs a power flush.
2 weeks before fitting a new condensing boiler I filled the CH system with X800, the CH system worked well with a very old Potterton boiler.
Gas safe plumber fitted a German condensing boiler and it would not fire and when it did would stay on for about 30 secs. Even changed the flow switch but still no joy. On the advice of a plumber mate he suggested changing over the very old Grundfos pump, still no joy but did find that there was quite a bit of sludge in the pipes after X800 treatment.
In the end called out the company engineer and after some checks said that the system is suffering from poor circulation, that new boilers are quite sensitive and that a power flush should be carried out to sort out poor circulation issue.
Very much regretting taking old the old boiler, might have been inefficient but did work."