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