Hydrogen Sulfide Gas in radiators - Advice needed

[Richard4241]

Hi all

Hoping somebody has come across this problem and can help with constructive advice.

History - 11 radiators in system (total volume 350 litres) steel radiators, copper pipework 20-25 years old. Magnaclean filter fitted and power flushed 10 Years ago with new inhibitor - never experienced any problems until...

New Vaillant Ecofit pure combi installed 18 months ago. Installer flushed system and put in inhibitor. (I question removal of flux.)

6 months after fitting, strange intermittent noises from Boiler every few days. Constantly having to bleed radiators but never need to top up system.
How's air getting into the system under pressure? Fitted an additional Expansion vessel just in case the in built vessel not big enough - No help. No leaks on system (Never need to top up system).

Vaillant engineer came out, found no problem but installed new diverter valve and bypass valve just in case. He suggested it could be Hydrogen in system. He was right, but i didn't check DOH! - Noise still persisted.

Just a theory - I blanked off the boiler auto bleeder. Noise disappeared.

My wife bled a radiator the other day and told me she smelt bad eggs.
I'm told that this smell is associated with hydrogen sulfide. Furthermore you can ignite the gas when bleeding - produces a mini flame thrower!
(Do NOT try this at home) Also i find the pH level is 9.0 - too alakline.

So finally we now know the problem - serious corrosion is happening inside the system and producing hydrogen sulfide gas. The new boiler's life expectancy is dwindling day by day. Need to get this sorted ASAP.

Going to drain/flush the system and put in 2 liters of Sentinel X400 cleaner in next few days. Leave for a week, then drain, power flush and put in 2 liters of Sentinel X100 inhibitor and hope this stops the corrosion/gassing. (Vaillant say NO Biocides.)

New radiators are in the garage, but because of elderly parents living here, plan on replacing these in Spring.

Am i doing the right thing? Or has anybody got any better ideas..

Thanks for reading. I'll report back with progress just in case some other unlucky person has this nasty problem.

 

[ShaunCorbs]

Needs a flush out even if it's just mains water and then cleaning

 

[Rob Foster]

The gas is produced due to reaction between , cast iron, copper and steel, and water makes h2s and h2. The chemical whichever stops this happening. It’s the ferric element ..the black sludge stuff that causes the trouble it’s like liquid sandpaper and wears out valves and pumps and the sediment blocks up the heat exchangers. The filter gets the stuff 5he chemicals don’t stop . I understand that you cannot put too much into a system except the cost factor . I good filter is essential ...I cannot tell you which I would choose as I designed 3 of the market leading ones but not the adey ones. Rob Foster aka centralheatking

 

[king of pipes]

A Complete drain down and a cold water flush before adding x400 and running for a week in the system as normal, get it hot as you can and hot flush - cold flush 2 litres of x100 fill vent test , done this needs doing every 5 years . Kop

 

[Inverness]

Two filters on the flow n return.

 

[Richard4241]

The gas is produced due to reaction between , cast iron, copper and steel, and water makes h2s and h2. The chemical whichever stops this happening. It’s the ferric element ..the black sludge stuff that causes the trouble it’s like liquid sandpaper and wears out valves and pumps and the sediment blocks up the heat exchangers. The filter gets the stuff 5he chemicals don’t stop . I understand that you cannot put too much into a system except the cost factor . I good filter is essential ...I cannot tell you which I would choose as I designed 3 of the market leading ones but not the adey ones. Rob Foster aka centralheatking

Thanks for advice. System has a Magnaclean, I thought this filtered out the black sludge. Is there another type of filter system? Any suggestions?

 

[Richard4241]

A Complete drain down and a cold water flush before adding x400 and running for a week in the system as normal, get it hot as you can and hot flush - cold flush 2 litres of x100 fill vent test , done this needs doing every 5 years . Kop

Good advice, thanks. I'll get this done in next few days.

 

[Richard4241]

Two filters on the flow n return.

Thanks for your advice. If problem persists after new radiators fitted I'll fit another magnaclean on t'other side. Cheers

 

[Richard4241]

Needs a flush out even if it's just mains water and then cleaning

I agree. Major flush due soon!

 

[Rob Foster]

Thanks for advice. System has a Magnaclean, I thought this filtered out the black sludge. Is there another type of filter system? Any suggestions?

Of course magnaclean filters ferric stuff , but there can be other particles which are very fine and none magnetic that also need filtering .

In fact I am half way to producing a system that will do away with all this stuff, it is backed by a big uk manufacturer

Rob Foster aka centralheatking

 

[Inverness]

Pour sludge remover or cleanser and leave it running in the system for a week or two.

 

[Scott_D]

Of course magnaclean filters ferric stuff , but there can be other particles which are very fine and none magnetic that also need filtering .
In fact I am half way to producing a system that will do away with all this stuff, it is backed by a big uk manufacturer

Rob Foster aka centralheatking

When will it be in production?

 

[Rob Foster]

When will it be in production?

I run API 2006. We are involved in 3 main projects at present. The Mfd by Flowflex, and 2 private devices. There will be room for this project between now and early 2019. We can only afford 2/3 projects at a time, avg cost £50,000 .
But yes watch this space. Thanks for your interest. Rob Foster aka centralheatking

 

[Rob Foster]

Of course magnaclean filters ferric stuff , but there can be other particles which are very fine and none magnetic that also need filtering .

In fact I am half way to producing a system that will do away with all this stuff, it is backed by a big uk manufacturer

Rob Foster aka centralheatking

There are a number of magnetic and non magnetic filters on the very crowded heating filter market. My personal favourite is centra mag by trappex, I have no commercial finger in this pie. Crucial factors in choosing a good filter are how fine is the non magnetic strainer, how strong the magnet and how easily it is cleaned but how the filter copes when full of debris.
Rob Foster aka centralhearking

 

[Inverness]

There's one out already ready that has a magnet and a mesh filter all in one. Magnaclean but it's purple in colour one of the first filters that came on the market.

 

[Rob Foster]

There's one out already ready that has a magnet and a mesh filter all in one. Magnaclean but it's purple in colour one of the first filters that came on the market.

They had terrible trouble at first magnaclean, it got de listed by BGas at one point, dodgy valves brittle casing, but they are better now. Market leader it is , but not the best in my opinion. Rob Foster aka centralheatking

 

[Ric2013]

Total volume 350 litres seems A LOT for 11 rads.

But if this is accurate then you need at least 3.5 litres of Sentinel as each 1 litre bottle will treat a maximum of 100 l of water.

 

[Scott_D]

There are a number of magnetic and non magnetic filters on the very crowded heating filter market. My personal favourite is centra mag by trappex, I have no commercial finger in this pie. Crucial factors in choosing a good filter are how fine is the non magnetic strainer, how strong the magnet and how easily it is cleaned but how the filter copes when full of debris.
Rob Foster aka centralhearking

The guy who invented the Trappex filter use to come on this forum, can't remember his name.

 

[Rob Foster]

Total volume 350 litres seems A LOT for 11 rads.

But if this is accurate then you need at least 3.5 litres of Sentinel as each 1 litre bottle will treat a maximum of 100 l of water.

Check some sentinel products can be diluted says on side
RobFoster aka centralheatking

 

[Rob Foster]

The guy who invented the Trappex filter use to come on this forum, can't remember his name.

Shaz nice fella met him many times Rob Foster

 

[Chuck]

Total volume 350 litres seems A LOT for 11 rads.

I suspect he meant 35 litres. He'd need about 2 miles of pipe for it to get up to 350.

 

[Richard4241]

First update. Today my engineer drained the system. We expected to see loads of sludge and contamination, but what came out was really really clean, there was a few small bubbles but no sludge or particles, however still alkaline at 9.0pH. We opened the magnaclean filter, hardly anything in there. After a good flushing, put in 2 liters of Sentinel X400 cleaner. So have to wait 2 weeks now before the next chapter. Also will be fitting a new filter, looking like a Trappex CentraMag 2 (Thanks Rob for recommendation).

Thanks to everybody for the helpful advice offered.

 

[Richard4241]

I suspect he meant 35 litres. He'd need about 2 miles of pipe for it to get up to 350.

Thanks Chuck. Some chump on internet claims 22mm pipe takes 1.5litres per metre. It's actually 0.305 litres per metre. So i'd need 3,762 metres of 22mm pipe - which is slighty over 2 miles!
Also the internet told me radiators take 11 litres per Kw - but i'm questioning that now. Any ideas?

 

[Ric2013]

I had some old-style heavy and solid single panel unfinned radiators in a previous address. Internet claims output would be around 1kW which seems about right. They actually contained 5.5 litres (or was it pints?) each. So much for old radiators being high water content. 11l per kW sound OTT.

 

[Richard4241]

Second Update. I got my system volume totally wrong at 350 litres. Is actually 93 litres. (Thanks Chuck). I've attached a chart for other users to correctly calculate water volume in a system. I've now drained/flushed system again (did contain 2 litres of Sentinel X400 cleaner) and now refilled with 1 litre Sentinel X100 inhibitor. pHlevel at 7. Here's hoping iv'e got rid of the hydrogen gas problem. Will update in a few weeks.

 

[Ric2013]

I'm a bit confused about this hydrogen sulphide issue. H2S would result from the anaerobic decomposition of organic matter, not as a byproduct of the oxidation of iron, which would, I think, be pure hydrogen. I'm not aware that there is any sulphur (S) to be found in a heating system primary circuit unless a bird has pooed in the F&E.

Feel free to shoot me down: chemistry always was my weakest science at school.

 

[Richard4241]

I'm a bit confused about this hydrogen sulphide issue. H2S would result from the anaerobic decomposition of organic matter, not as a byproduct of the oxidation of iron, which would, I think, be pure hydrogen. I'm not aware that there is any sulphur (S) to be found in a heating system primary circuit unless a bird has pooed in the F&E.

Feel free to shoot me down: chemistry always was my weakest science at school.

Hi Rick. Can confirm no bird or any other animal has poohed in my system. It's the rotten egg smell and Sentinel's website that lead me to beleive it was hydrogen sulphide. Since cleaner & flushing, the gassing (whatever it was) seems to have stopped.... so far. Thanks for your comments - sounds plausible.

 

[Richard4241]

Third & Final Update. Problem solved.
System drained (yet again), new magnet/vortex filter fitted then used Sentinel X300 cleaner to get rid of flux from new pipework, flushed out, refilled system and put in 1.5 litres of Sentinel X100 inhibitor.
No more hydrogen/hydrogen sulfide/hydrogen sulphide gas and no more gurgling noises or gas in the system!
Thanks to everybody for their help and advice and hope this thread helps others. Cheers and a Merry Christmas to all.