Does my central heating system contain a corrosion inhibitor

mark55man

Am looking to buy a bathroom towel radiator and the website information states 

"NOTE: This product must be fitted to a central heating system that has been treated with a corrosion inhibitor"

So my question is how do I tell?  And what happens if I'm wrong

Thanks in advance 

[Deleted User]

Ask whoever services it. If its not been been done in a year, you'll probably want to top up.

Not having just means that corrosion can take place faster.

mark55man

OK thank you - serviced by BG last spring.  I will organise another service and make sure to ask for a top up.  I have added pressure (ie water) a couple of times since then

Thank you - so that would be corrosion inside the radiator - which will take a while I guess, but would result in leaks in the worst case 

Bendy_House

Hi Mark.

(AfaIk, testing the inhib level is not part of a routine boiler service - you'd have to ask for it separately.)

ALL systems should contain inhibitor. All would (should) have had inhibitor added from the outset, but over time this can become depleted with, say, system pressure top-ups (ie some water lost, and replaced with fresh), radiator swaps, boiler repairs etc.

So, is there enough inhibitor in your system? Dunno. Could be. Might not. Dunno.

I hope that helps  

How to check? Well, if you know the type used ('make', for example), then you can buy testing kits. I doubt many plumbers bother with that (but I don't know - any plumbers on here confirm, please?), but instead will top-up the additives if they've done significant work on a system that involved the loss of water. For a full drain-down, they'd obviously add a full dose.

It ain't an exact science - you'll find bottles of inhib typically treat a 'standard' system of up to 10 rads or similar. For larger systems, 'stick in two bottles'... So, clearly, a bit too much ain't going to cause harm.

More important is, I think, for you (or your plumber) to try and check if there's any corrosion taking place in your existing system. Is your new rad going to replace an existing one? If so, the old one can be checked for black sludge inside it, which is what happens if a system starts to corrode (ie not enough inhibitor). If this is found, then really the whole system should be drained down and started again, with a magnetic filter added (a good idea anyway), fresh inhibitor, and also a long-term 'filter aid' that gradually help to shift that sludge, which should be caught by the filter (which is checked every couple of months initially). (Fernox do a combined product, but it seems hard to find/not popular for some reason?)

Soooo, if your plumber is going to be draining down your system in any case (ie if this rad is an addition to your system, or the pipework requires significant changes to make it fit), then you'll have a fresh dose and should be fine. If the rad is just a 'swap', so no system drain-down, then ask the plumber for their thoughts on the water coming out, and to add a wee top-up of inhib, pleeeeez.

And if you don't have a mag filter, perhaps a good time to fit one.

FaceHead

As above, you can test, but why bother when too much will do no harm. 

As inhibitor gradually breaks down, if you don't know you have the right amount in, you probably don't. I'd suggest that you chuck more in - enough for your whole system - and that should keep you out of trouble for the foreseeable. 

(Upstairs) Towel rails are often the easiest place to put inhibitor in. It's the top of the system, so you can just let a little pressure off, pop the top off and pour it in. The fitter will likely do it for you, so just pop down the shop and grab a bottle for them. 

The fitter probably won't drain the whole system down (for an upstairs Towel rail). Either they'd just let off enough pressure downstairs or freeze the pipes. 

mark55man

Thanks very much that makes perfect sense.  The radiator is a direct one for one replacement - no other plumbing work anticipated, or indeed any current plumbing problems.  The boiler was replaced 10 years ago, and has largely been left alone, apart from  HIVE upgrade a few years ago which was just the controller really  

mark55man

As a thought when the work is done, I will get the plumber to do a test and if its low, then I can ask him to top up the main system, and if its fine that's good, and if it takes a week to get back to it, nothing is going to corrode in a week 

markin

If its not had work done in 10 years just add it no point testing

Belenus

FaceHead said:

.

(Upstairs) Towel rails are often the easiest place to put inhibitor in. It's the top of the system, so you can just let a little pressure off, pop the top off and pour it in. The fitter will likely do it for you, so just pop down the shop and grab a bottle for them. 

I use this type of product that is injected via the filling loop.

Fernox F1

It is a bit pricier so perhaps not MSE but it is easier to use.

£15 every few years won't break the bank.

Bendy_House

mark55man said:

Thanks very much that makes perfect sense.  The radiator is a direct one for one replacement - no other plumbing work anticipated, or indeed any current plumbing problems.  The boiler was replaced 10 years ago, and has largely been left alone, apart from  HIVE upgrade a few years ago which was just the controller really  

In that case - at least if the valves are being kept - then the system won't be drained down, just that towel rad swapped.

I'd ask their opinion of the system condition - this can usually be seen by the colour of the water ('brownish' usually indicates sludge) and especially if there's black sludge in the old rad.

If you ask, they'll certainly add another dose of inhib, but I doubt they'd bother testing the existing level. The plumber might even say the water clearly has enough inhib in it if they reckon it's 'obvious' - expected chemical smell, etc.

Why are you replacing the old rad - aesthetics, or corrosion? For the latter, internal or ext?!

Another_Level

As above have inhibitor added anyway, dont want the towel warmer internals corroding