Damage from inhibitor?

[al]

Standard warning on the back says some boilers/pumps might be damaged by it. Is that common? No idea what make my pump is and I've a 9 year-old Glow-worm boiler - is there any point in worrying at all about it or should I just lash some in?

Have just spent ages scooping out un-utterable s**te from the bottle of the heating tank as three full system flushes hadn't got rid of all the brown (actually ran cleaner originally, but disturbing the sediment by emptying/filling the tank got it all suspended in the water!). 1/2 the house on new rads now ... don't want them to be rusting anytime soon ..

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[Set Square]

On a related issue, I shall soon be flushing out my system and renewing the inhibitor.

Are there any issues in finding an inhibitor which can cope with:

• cast iron heat exchanger in boiler

• steel panel radiators

• mainly copper pipework

• some (recently added) JG-Speedfit (plastic) barrier pipe?

[Andy Hall]

This is very standard. Fernox MB-1 is a good choice for it.

[Dave Plowman (News)]

That sounds like a real reason to use inhibitor - although if the header tank is full of crud it suggests pumping over at some time.

[al]

You mean the pump rate was too strong and hot water came back into the expansion tank? Is there any reason for that to happen naturally in a system if you don't change anything?

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[al]

Think the stuff I saw was Wickes home brand. Is there anything in the name with such a solution?

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[Dave Plowman (News)]

It depends on whether it was correctly set up initially.

[Andy Hall]

Well.....

I tend to think of it this way....

I've used MB-1 in every system that I've had up until a couple of years ago when I switched to a sealed system and the gel equivalent is more convenient. It costs £15 about every two years and every system has been clean and sludge free apart from a few copper particles from the original plumbing work.

If you consider that you are protecting a system which will cost about £2k to replace if you DIYed it and at least twice that if done professionally, then I don't see the point in attempting to save £5-8 by buying an unknown product from a DIY shed.

Fernox and Sentinel are the specialists in this area, and I prefer to buy what I know works and that I can test.

It may well be that the shed products are OK, but for the stakes and the small saving involved, I really don't think it's worth the risk.

[Ed Sirett]

home brand. Is there anything in the name

I'm fairly sure that MB-1 is NOT compatible with aluminium components. Fro such a system make sure you use Sentinel X-100.

[al]

Fair enough. Only reason I was looking at Wickes brand was convenience, not price. Do you know any of the big shops/sheds that stock it? Would save me having to mail order a single item!

I see it comes in 4l and 25l containers. How much is enough for an average system? I know it's hard to judge, but in case it helps, these are the rads I have:

4 x small (0.5 - 0.6m) doubles 2 x medium (0.8m) doubles 1 x small (0.4m) single 1 x large (1.4m) single

... and a wee expansion tank in the attack, the amount of water in which I could not guess but it's about the size of a kitchen sink (the "sunk" bit that is!).

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[al]

At the risk of it sounding like a dumb question ... how does one find out? I know I've got copper pipes and steel rads, but I've no idea what the boiler is made from (9 year old Glow-worm).

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[Andy Hall]

I didn't think so, Ed, although I've never had a boiler with aluminium heat exchanger.

Unfortunately Fernox's web site is down at present, although a couple of sites I found with spec sheets say it is OK, eg.

descaler isn't compatible with aluminium. Were you thinking of that?

[Andy Hall]

Depends on the model. I would call the manufacturer and ask.

[Andy Hall]

4 litres will be enough for that.

In his other post, Ed mentions that he didn't think that MB-1 is compatible with aluminium. I thought it was, but Fernox's web site is broken at present so I can't check there. Some other sites have manufacturer data sheets indicating it's OK. He mentions Sentinel, which is another known good product.

I've seen Sentinel products in B&Q and Fernox in Homebase (but expensive).

You could try the plumbing merchants like Plumbcenter, Travis Perkins etc.

[al]

I looked at their site last night and I *think* I remember seeing it say it was suitable for all pipe and boiler types. Will have a look out for it in the sheds. It's £15 on Plumbworld .. presumably for a 4l bottle, so will use that as a benchmark. Thanks for all the suggestions.

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[John]

MB1 used to be incompatible with Aluminium but I have an idea its recipe was altered to overcome this problem. However since Sentinel X100 "is" compatible I tend to use it for all jobs nowadays

[Ed Sirett]

I'm pretty sure that I saw the warning on some inhibitor. It was some years ago and I might be wrong.

Given the amount of emphasis given by Sentinel that their product is compatible with Al, it's likely there was at least one product on the market that was not compatible.

[Ed Sirett]

Which just shows how long it is since I used any Fernox MB1.