How much inhibitor?

[RF Lighting]

Hello. I need to drain my heating system down to do some work on it. I was wondering how you calculate how much water is in the system to add the correct quantity of inhibitor when refilling? Is it possible to add too much or just a waste of money?

Thanks.

 

[lightning]

1 litre for 10 rads

Paul

 

[Richardthe3rd]

Or 3litre if it's X100!!

 

[JohnD]

if you can be bothered, you can drain it out into buckets and measure it. I did that once, and it came to 100 litres total, near enough, including F&E, Cylinder circuit, and big iron boiler. With a new modern boiler it will be somewhat less. Ten rads, some of them quite big doubles. One bottle is about right.

Is it an old open vented system? You might take the opportunity to give it a chemical clean before draining.

 

[RF Lighting]

Yeah it's an ancient open vented system with a one pipe circuit upstairs. Part of the reason for draining is to fit a magnaclean. How does the chemical clean work? Just pour it in the system and leave it a week?

 

[JohnD]

tie up the float in the F&E, bale it out and sponge it clean (it will contain mud, rust and drowned wildlife)

then drain out one or two bucketfuls of water from the drain cock

then pour your cleaning chemical (I like X400 but it is very mild and you leave it circulating for weeks, use X800 if you want to drain it out same or next day) into the F&E and untie the float, stir it in and it will be drawn down into the system as it tops up, which you can then turn on and let it circulate hot.

If the circulating water (tested at a bleed valve) turns jet black, that's a good sign, it's the sediment being loosened and washed away into the water.

You mention a one-pipe system, which is difficult to clean. You could take off the rads and hose them out in the garden, and/or add Sentinel X900 on final fill (when you add the inhibitor such as X100). It is intended to be left in permanently, not drained out, to loosen sediment so the Magnaclean or other filter can trap it.
http://www.sentinelprotects.com/uk/products/domestic/central-heating-systems

Empty out the Magnaclean once a week at first, it will collect plenty. Then when it is almost clean, empty it once a month, then when it is almost clean, once a year. It is very pleasing to observe how much sludge has been captured.

This is much easier and cheaper than a powerflush, and unless you leave it too late, so pipes are actually blocked, it will often do the trick.

 

[Richardthe3rd]

John.
I test new to 1year old installation on a daily basis. Systems that have been cleaned with x400 & treated with x100.
I'd never recommend x100, it's far too weak & diluted compared to Fernox products & others. Sentinal are recommending any system is treated with x100 once a year!!!

 

[JohnD]

that's odd. Is the oxygen-scavenging exhausted?

What are the recommendations for Fernox, in open systems?

 

[D_Hailsham]

Sentinel are recommending any system is treated with x100 once a year!!!

Where did you read that? Link please.

 

[ScottishGasMan]

Hello. I need to drain my heating system down to do some work on it. I was wondering how you calculate how much water is in the system to add the correct quantity of inhibitor when refilling? Is it possible to add too much or just a waste of money?

Thanks.

Normal rule of thumb is 1 litre of x100/f1 (I preffer fernox but they might all be the same, you'll never know) per 10 single radiators, if there doubles then you should double it up.

You can add to much which then produces froth in the pump and stops circualtion so dont go crazy with it thinking more is always better, but its not an exact measurment so dont get to caught up on it, you need to go quite over board before too much is the problem.


as far as flushing goes, ideally, you drain down the whole system (including opening all the radiator bleed points to let air in and all current water out. while its empty give the F+E tank a clean out if it needs it so you dont fill it with the carp from there.

while its drained fit the filter, then add cleanser and fill+vent system, let it run for a week or so depending on the type you use (stay away from stronger products like x800 or anything that requires to be neutralised)

when ready, drain system fully as before, open filter and clean, refill system (dont add any inhibitor yet, vent and run system till you have circulation again.

Then repeat drain down. To do it right can be anything from 2 or 3 drain downs to a dozen depending on your system, youll know when your good as the water draining out could fill an empty bottle of coke or similar and be colourless (if its still got a strong tint of colour (brown) then theres still cleanser in there and you want it all out.

Once thats done, fill with water and inhibitors vent and run system, I usualy add another bottle of inhibitor in the F+E tank after (assuming you have one) so when bleeding rads in future or as system water is replaced in time it doesnt dilute as quick.

 

[Richardthe3rd]

Sentinel are recommending any system is treated with x100 once a year!!!

Where did you read that? Link please.

That is what Sentinel told us when we complained about the poor performance of their product. If fact they were quite rude, as if to say we're the experts, how dare you question our product!!

 

[D_Hailsham]

Sentinel are recommending any system is treated with x100 once a year!!!

Where did you read that? Link please.

That is what Sentinel told us when we complained about the poor performance of their product. If fact they were quite rude, as if to say we're the experts, how dare you question our product!!

I can't find anything on the Sentinel website to back this up.

 

[RF Lighting]

One more question. I already have inhibitor in the system. Do I need to drain down and fill the system with clean water before I add the X400 or is it ok to put it straight in?

 

[JohnD]

you can lob it in. It is very mild and not acidic or aggressive.

If you think the previous brand might be incompatible, you can call Sentinel. They usually discourage mixing inhibitors, but that might just be to make you buy more of their own brand.

 

[RF Lighting]

Promise this is the last question! Is there a maximum amount of time that it can be left in the system vs most effectiveness for the product?