Last year I installed a couple of cast iron radiators with new copper pipe and soldered joints. Prior to the radiators going in I cleaned the whole system with x800 and flushed. Following the new soldered joints the system was cleaned with x300, flushed and has been running since with x100 on board. About a month ago there was some water leaking around one of the cast iron radiators bushes- stopped with a quick nip up. More recently I have noticed that there is wetness between a number of sections of the radiator in addition to a white/tan crustiness on the rubber gaskets. The wetness is very black and almost oily (water in the system is clear). On contacting the company they state that phosphoric acid within the x300 has likely broken down the silicon gaskets between radiator sections resulting in the premature failure. Does this sound reasonable? Surely if I don't clean the system I would have acidic flux floating around and causing similar issues- can't win! As there is x100 in at present does this not work similarly to dissolve the iron oxide? I can't not really have no inhibitor. Anyway they are replacing the radiator that has failed (didn't expect) and are going to inspect the one that I remove.
I doubt any of the experienced contributors to this forum have sufficient knowledge about the chemical compositions of the different Sentinel products and what their effects are on the silicone gaskets used by the radiator manufacturer. If you decide to enter into the fray, my guess is this going to involve much frustration with Sentinel and the radiator manufacturer blaming each other. A huge amount of your effort will result in absolutely nothing. Been there ... done that ... and don't advise anyone to go there ... in fact, strongly advise NOT to go there.
I was more concerned that inhibitor was being blamed for silicon gasket failure. They state not to use acidic flux but not what inhibitor to use and surely they can't be advocating to not use any and I would hope all systems contain it. Just at a bit of a loss as it seems that it is an easy get out for any future failures. I either have to run without inhibitor and have a corroded system or add inhibitor. They are replacing a small and comparatively cheap easy to remove rad whereas we have much larger, expensive and difficult to replace units.
Total BS I say, but contact Sentinel,they will confirm whether true or false. Senntinel X100 has a pH neutral formulation, & is totally safe in cast iron radiators, it's suitable for all metals.
Sans protection, copper in contact with iron (or steel) in the presence of an electrolyte will result in the preferential corrosion of the iron since iron is higher in the electrochemical series than copper. Several million central heating systems use copper pipes and steel radiators, and some form or corrosion inhibitor is pretty much always added. Sentinel is fine for all common material combinations and should not cause a problem with CI radiators.
The cast iron is not the problem but the silicon gaskets...apparently. Just going through all their t+c's "No caustic/corrosive/acidic plumbing compounds or liquids are to be used on or in any part of our radiators, our valves or connections including aggressive flushing agents. If required, the system should be flushed with clean water only. The water in the system must be neutralised correctly following the use of any compounds etc if required using appropriate crystals or similar. If caustic and/or corrosive compounds (liquid or other) have been introduced into the system resulting in subsequent damage to seals/gaskets, any guarantee offered will be invalid. When a chemical cleanser is used it must be thoroughly flushed from the system. We recommend the use of Fernox F5 for power flushing and F1 rust inhibitor. " So it suggest to have no inhibitor and to flush all residue / flux with clean water which imho not work and will remain. Odd how they suggest that if you are to use an inhibitor you should use fernox. I was under the impression they all worked in a similar way. Deal with each other? TBH I think it is a bit irresponsible to suggest filling a lump of iron with warm water without inhibitor and expecting rust not to ensue. Have fitted lots of rads over the years so don't really go through instructions with a fine tooth comb...particularly about what brand of inhibitor should and shouldn't be used.
Sentinel X300 & X100 are non-acid, non-caustic product & ph neutral formulation,so ain't going to harm a slicone washer,
Sentinel agree- BS I tend to leave the sentinel cleaning products in the system for longer than is suggested but as I thought and Sentinel confirmed this, if left they just stop working. No detrimental effects. Plus the x300 was in the system prior to the rads going in and was flushed afterwards. As you state KIAB they also state they are non-caustic so I strongly doubt that the inhibitor is the cause of the radiator failure.
X300 does contain phosphoric acid and phosphoric acid does attack silicones. However, you'd have to use a rather more concentrated solution than X300 AND you'd have to have failed to flush the system out after using it.
It's more complex than just pH. For example, turpentine and silicone don't go well together - cleaning a radiator with turps where the fluid gets on the silicone gaskets could theoretically cause this problem.
No turps or similar on the radiators. x300 was in the system but gone before they went in. Now have the faff of removing the radiator..my evening sorted. Annoyingly I made nice sapele wood plinths with brass inserts that the feet sit on. The brass that has been dripped on has gone black and horrible but will likely come up with a bit of a polish. The wood however also has a few black drip marks that I fear will be permanent.
Sounds like the radiator manufacturer is trying to weasel out of a problem caused by their own quality control failure. As for stains on the wood, just tell people you paid extra for them to add character and they'll all be wanting the same thing
This is what I am talking about regarding the brass and wood staining. You can tell I like cleaning eh?!
I thought of that but it has routed brass inserts and edges. Underneath the brass it is screwed to the floor. Plus I would have to plane, re-do all the routing/ inserts, sand and then varnish...going to live with the imperfections. Enough hassle to lift the thing on my own!
The biggest value of forums like this is the knowledge sharing, but another value is the naming and shaming of shoddy products and services. I'd suggest getting back to the radiator manufacturer and telling them you want their mess sorted (in whatever way you'd be most satisfied with) or you will let all of us on the forum know which products we should all studiously avoid in future.