hydrogen in central heating

[darren bastin]

I installed a central heating system a year ago . The sysem was cleansed , flushed and inhibited but it continually fills with hydrogen ( can burn it off when bleeding). Fitted a combi, rads , copper pipework, the system is small only six rads 1 lit of inhibitor was added originally. I have had many similar in jobs in this area, using the same rads and boiler etc and not had this problem. I have flushed the system again and added more inhibitor hoping the problem will go away. Any offers of advice ?

 

[diamondgas]

Hi Darren ... I've had similar occur when the original system prior was pumping over..... I believe the inhibitor manufacturers supply test kits for checking the ferrous and copper content in the system water so you can make sure it's clean before you inhibit. It's all down to electrolytic action my aged grey matter prompts me lol ... may be worth Googling, it could help understand what's going on in the system

 

[hammers4spanner]

Never done your pipework properly underfloor imho ,
prob to many places for compressed air pockets and micro bubbles that are slowly becoming unsettled, i come across it so many times people unaware of how to install a pressurised system .

 

[diamondgas]

Just done a search to double check what my memory banks were saying Check out this for a read Corrosion and plumbing London, decorators, plumbers, electricians and office refurbishments Extensions

 

[hammers4spanner]

Just done a search to double check what my memory banks were saying Check out this for a read Corrosion and plumbing London, decorators, plumbers, electricians and office refurbishments Extensions

Not sure this would be the case in this scenario tho as its a year old system , electrolisys needs more time to cause the levels the op is talking about ,well more than a year imho.

 

[diamondgas]

I ain't no chemist H4S but if it's hydrogen then this is the only way it's produced me thinks, unless you know of another way? Who knows ... The op's asking for advice to overcome the hydrogen issues ... I'd recommend a thorough flush out again and testing the system before inhibiting? Iron/copper particles in the water will increase the potential for electrolysis to occur I believe? As said it's been some time since I researched all the gubbins on how sludge was made

 

[darren bastin]

The pipework was notched into the first floor joists, any pipes cossed were done with pulled bends and not sharp fittings , no convoluted pipework and surface drops to downstairs rads. All the runs and levels were straightforward so I dont see the how there could be pockets of compressed air etc. The rads are not venting air. By the sounds of it flushing and Inhibiting should cure it.

 

[hammers4spanner]

it may be but i would think there isnt enough dissimilar metals in a combi system to cause galvanic issues,dissimilar metals do cause hydrogen to build up but in space of a year would suggest a misuse of something somewhere or something overlooked or sheer misfortune.
i would suggest its an install issue in my install experience as in poor pipework installation ,easy way is to take water sample and send it off get a read out back and go from there

 

[hammers4spanner]

Whats the boiler ? cheap rads and valves???

 

[dancinplumba]

are pipes supplementary 'earth' bonded ? there could be an earth leakage, this could cause/speed up corrosion/electrolytic action ???
or i am talking tosh..just a thought

 

[darren bastin]

Its an Ideal Independant c24, K rads and standard valves . I again maintain that I have used the same materials , in the same water area without any issues. I have seen lots of pipework which has been slung in , no felt, no clips , no support and too many fittings. The installation pipework was done properly.

 

[hammers4spanner]

Well your situation says you have done something wrong somewhere.

 

[diamondgas]

You mention downstairs being fed from droppers Darren yeh? there may lie a lot of gunk Power flushing is good but in my experience is still challenged when it comes to dropper systems or microbore! Good old days we use to remove the radiators take them out side and swing them about to slosh out as much of the crud as possible To me it sound like it needs further cleansing ...?

 

[zzzjim]

Does this boiler run notably hotter that the other installs ?

 

[Howsie]

Not a bad idea at all.

Does the OP have a new consumer unit?

 

[darren bastin]

The boiler does seem to run hotter , the rads do get very hot , just put this down to it being such a small system. The hose was renovated and did have a new consumer unit. What are your thoughts ?

 

[zzzjim]

Still have no idea what is breaking down , but higher system temps will make it happen quicker

( Probably some old inhibitor residue/or gunk mixed with new stuff
and not getting along )

 

[hammers4spanner]

electrical current issue ?, still think something has happened somewhere to pipework on install.

 

[darren bastin]

Could you give me examples of what type of things on the pipe installation could cause corrosion please

 

[dancinplumba]

flux residues, strong cleanser left in system, too much inhibitor, aggressive water, earth leakage ??
imo

 

[hammers4spanner]

in my install experience have come across it a couple times on relative new systems where hydrogen has been released due from poor install as in creating points of trapped air under the floor when system is full which eventual causes probs . i wouldnt suggest materials you have used would be an issue on modern heating system .I am aware of electrolitic action from electricity but thats beyond me .

 

[darren bastin]

Surely if you had trapped air under floor then a symptom of this would be poor circulation , one or more rads would not work or need the air chasing out. To be honest when you flush and fill the system every rad comes up with no probs. All the drops have drain valves so the cleanser could be fuuly rid from the system.

 

[hammers4spanner]

No not really compresses as under pressure or can be micro bubbles , sure on some inhibs it states on them air creates corrosion which can be prevented by inhibitor etc etc .

 

[Mike Jackson]

I had this on my own system years ago. It was due to a bacterial contamination. I had to flush and disinfect the system to cure the problem. I wouldn't have thought that bacteria could survive the high temperatures in a combi circuit but they obviously can. That was around twenty year ago and no problems since.

 

[aggis]

Take a look at http://www.kamco.co.uk/GuidanceNotes/PDF/Gassing.pdf

 

[diamondgas]

You can obtain a kit and send away a sample for testing here SystemCheck Test Kit | JetFlush and Test Kits | Central Heating | Sentinel central heating products. ... May be worth giving sentinel a call to find out how much it would cost Darren. Could save you a lot of time

 

[mylesy]

Never done your pipework properly underfloor imho ,
prob to many places for compressed air pockets and micro bubbles that are slowly becoming unsettled, i come across it so many times people unaware of how to install a pressurised system .

pressurised systems are less likely to have small air pockets in them, the air is forced out even if it is installed poorly. how would YOU lay your flow and return pipes differently to an oppenvented system?? i would do it exactly the same in either case imho only instead of the point on the system where theirs a tank their would be an un-vented set up.

 

[mylesy]

anode and cathode. if you put a piece of copper in a potato and a piece of magnesium in the same potato but at the other end and you have a wire from each piece of metal with a volt meter inbetween you get voltage!! like a very **** battery. the potato acts as the buffer. on the electrolytic table copper is very high up and eats most other metals in the system.

 

[darren bastin]

Thanks for all the input lads. The bloke who owns the prop is a sparky so I can get him to check for earth leakage etc. Mike do you know what disinfectant you used , If the problem persists I dont want to add something that is not correct? I can except that I may not have got all the original cleanser out ( although drain points on every drop to help), I am struggling to cope with the idea that my work is rough ! If this was the case all my installs would be plagued by this problem and they aint. I will update .

 

[MattWeth]

You can obtain a kit and send away a sample for testing here SystemCheck Test Kit | JetFlush and Test Kits | Central Heating | Sentinel central heating products. ... May be worth giving sentinel a call to find out how much it would cost Darren. Could save you a lot of time

This only works if you've dosed with Sentinel X100. I've spoken to Sentinel about this very issue as I need to check a large system with unknown or indeed no inhibitor. They informed me that it isn't a full chemical analysis, just a check for the concentration / efficacy of X100.

As an aside, I think it slightly 'cheeky' that H4S should immediately assume (and then repeatedly state) that the problem is the OP's installation practices. "IMHO" ...

 

[diamondgas]

Thanks for all the input lads. The bloke who owns the prop is a sparky so I can get him to check for earth leakage etc. Mike do you know what disinfectant you used , If the problem persists I dont want to add something that is not correct? I can except that I may not have got all the original cleanser out ( although drain points on every drop to help), I am struggling to cope with the idea that my work is rough ! If this was the case all my installs would be plagued by this problem and they aint. I will update .

Darren shrug it off ... You know the quality of your work and TBH dropper systems are a pain, if microbore, even worse...! Good luck getting it sorted. I was serious about taking the rads out side and running a hose through them by-the-way ..

 

[hammers4spanner]

This only works if you've dosed with Sentinel X100. I've spoken to Sentinel about this very issue as I need to check a large system with unknown or indeed no inhibitor. They informed me that it isn't a full chemical analysis, just a check for the concentration / efficacy of X100.

As an aside, I think it slightly 'cheeky' that H4S should immediately assume (and then repeatedly state) that the problem is the OP's installation practices. A little conceited, "IMHO" ...

sorry for making any input on an open forum quite obviously notin the plumbing elite on here !!!

 

[Mike Jackson]

Thanks for all the input lads. The bloke who owns the prop is a sparky so I can get him to check for earth leakage etc. Mike do you know what disinfectant you used , If the problem persists I dont want to add something that is not correct? I can except that I may not have got all the original cleanser out ( although drain points on every drop to help), I am struggling to cope with the idea that my work is rough ! If this was the case all my installs would be plagued by this problem and they aint. I will update .

Can't remember now but Fernox do one. Biocide AF10

 

[FD Powerflow]

What inhibitor are you using Darren? might be worth a call to their tech helpline

 

[darren bastin]

Sentinel x100. I should know within a week or two whether flushing and re-inhibiting has been successfull. If not its out with the powerflusher and start again !