Central Heating Additive

The whole thing's a rip off because AFAIK the main ingredient in Sentinel (and possibly the rest)is boric acid, which is dirt cheap and pretty easy to get hold of

"John" wrote

It's once in a blue moon this so go for quality/brand. Either Fernox or Sentinel. Fernox have good tech support, so ring them and tell them all the component parts in your system (boiler specifically of course). They will advise the appropriate inhibitor - probably MB-1 at a guess. Then ring round for best stockist price!

Phil

I've always used Fernox MB-1 or Superconcentrate gel in systems for over 30 years. Typically it's one dose per 2 years to maintain the required level at a test from what I've found.

The current system is now 20 years old and remains as clean as a whistle.

There certainly have been nail in jar tests done by people in this group and it has been found that the cheap products don't perform as well.

The economics are straightforward enough. Fernox or Sentinel cost £20-25 for a treatment, so on average about £15 a year.

The cheap unbranded stuff costs around £8, so being generous £5/year.

So the discussion is about saving £10 a year on a system that would cost £3000 or more to replace.

I am very surprised that anyone would even ask the question as to whether it's worth taking such a risk vs, using known good products.

Very unwise.

The discussion becomes one of chancing some unknown product and saving £10 per annum at the risk of wrecking a £3k heating system.

Fernox and Sentinel are known good products that have been on the market for decades and have a proven track record.

The rip off would be the person themselves using something of unknown track record and quality and then wondering why the system has disintegrated.

Gledhill recommend Fernox over Sentinel as it has anti-biology growth additives.

I would agree on this one. I generally use Fernox MB1. If you buy from Screwfix, I think MB1 is about £18. Sentinel seems ok, but I don't know if it would be a bad thing to topup with different 'brands' of inhibitor.

HRPC or whatever they are called now stock Kamco branded inhibitor for about £10 in the same size containers that Sentinel use. Kamco say on their training course that using some inhibitors is worse that none at all.

Martyn

Thanks - Fernox again then. Who knows I could have had an almighty response saying that there is something better / more cost effective on the market now.

Yes, I remember the photos being posted on this ng - I'm sure googling will find them if the 'tester' himself doesn't stand up!

David

I think it was Andrew Gabriel but not certain.

Boric Acid? Are you sure? Are you a chemist or something?

The final pH has to be alkaline so I don't think an acid would be involved. IANAC. I think it's sodium molybdate in Sentinel & Fernox. I also know of sodium sulphite being used as an oxygen scavenger and sodium hydroxide being used to adjust the pH to alkaline. Nitrites are used in cheap stuff allegedly. However, they won't disclose what the active ingredients are, so you can't test it without paying them a huge wad of wonga for their test kits. Huge volumes of inhibitors must be discharged into the drains and renewed every year when a simple test of the levels and a top-up of the active ingredients would be most cost effective. All water treatment companies are similar, selling 'Super Formula X' for mega-bucks when they purchase it as cheap bulk chemicals. It has always been thus. The cost of corrosion damage makes the inhibitors a sound investment, despite this.

I don't think the nail-in-jar test is very effective, the corrosion rate depends on the rate at which oxygen is getting into the solution, so removing the solution from the system does not make for an good test. A corrosion coupon rack is the proper job way to do it

In message , Doctor Drivel writes

and has sorted the mould growth in my header tank for the last n years.

Boric acid seems to be very difficult to get hold of nowadays. Once upon a time (a year or two ago) you could buy it easily from any local 'chemist', but apparently it became popular for preparing certain "drugs ;-(", hence most local pharmacies have discontinued it - another example of the nanny-state in action.

I'm sure it'll be available on-line from your friendly e-meds/Viagra suppliers.

No, but I can read a safety data sheet

Sentinel X100 is PH6.4 IIRC

Plenty on EBay, and probably available at garden centres.

No that's for making plants grow, not other things.

Dim the lights, and impress Madam with the size of your cucumber...

Owain

OP

Fernox seem to have 3 similar offerings (at Screwfix)

Alphi 11 F 1 MB 1 Can't really see the difference!

I have used MB 1 before and Sentinel products.

I guess I will get MB1

MB-1 is the product suitable for standard systems and has been on the market for donkey's years.

F1 has the same characteristics and can be used interchangeably with MB-1 unless you want to use the gel superconcentrate in a sealed system for convenience. F1 is a newer product.

Alphi-11 is a very diferent product. Apart from being an inhibitor, it has an antifreeze component. Commonly it's used in solar heating systems. I've used it in a secondary circuit to my workshop because of the risk that the circuit could reach temperatures below 0 degrees if the circuit were turned off or heat supply wasn't there. It's a lot more expensive than MB-1 because a larger quantity is required - e.g. I run that circuit with 20% of Alphi-11.

Boric acid has a variety of uses. Buy it where you like. Buy it from Sentinel as a 5% solution in water if you prefer