Flamable Gas In Closed Heating System

Aidan (UK)

It is hydrogen.

The water is being broken down by electrolytic/bi-metallic corrosion, involving the copper and ferrous components. You need some chemical water treatment.

Some technicians here will vent the gas from the radiator vent and try to ignite it. If it lights, it's hydrogen from corrosion. If it doesn't light it's air. I've never tried this in case it should prove to be a mixture of both!

D. Freeman

Flammable Gas in Closed Heating System

I have a mystery to solve and hope readers can help. I have a customer that is getting flammable gas out of his air vents on a closed heating system. We are not sure what this gas is but testing confirms it is flammable (Hydrogen perhaps).
We have certainly checked out the obvious such as gas line cross connections and it is not that.
System is 4 x 3000 mbh fin tube boilers. 10% Propylene glycol solution in a closed heating system.
Gas was detected about 2 years ago and a chemical corrosion inhibitor was added to no effect. Gas is still occuring.
Any ideas? Please advise. Thanks a lot.

D. Freeman

Unknown

It's likely alcohol

Propylene Glycol, specificlly.

Noel

DaveGateway

Gas

Water is H2O. One part hydrogen and two part oxygen. Water can break down and give up the hydrogen gas which is very flammable. Your water heater can do the same thing just read the warnings that come with it. But how did you find out it was flammable?? Good luck!

MikeB34

I had

I had a situation in a semi-rural area similar to this. Seems there was a gas well in the area and Natural gas would seep in to the well water. The relief blew on the HWH and when the fumes exited the overflow tube, they hit the main burner flame and lit up like a torch...could it be something like that I wonder?

Eric Taylor_37

ADG

I have herd that you can get organic stuff in your fill water that then breaks down in a closed system anerobically (without air) and creates anerobic digester gas (ADG). ADG is basically dirty methane. If you were creating Hydrogen by seperating water with electrolysis then you would also be creating Oxygen. A mix like that is very explosive and would not simply burn. It would be like lighting an Oxy-Acetelyene torch with both gasses on. Touch off a stored volume that is already mixed in the right proportions and your in for a real show! We used to stuff a Nerf football into a length of capped PVC and fill it with the Oxy torch. Ahh, the good ol' days.....

Be careful out there folks!

Eric

Aidan (UK)

electrolysis

I think the oxygen dissolves in the water and then attacks the ferrous components, converting them into good old rust. The hydrogen is relatively insoluble so it remains in the system until it is vented.

I've been told this tale about igniting the hydrogen several times. Although I've never witnessed it, I'm fairly sure it is done. The possibility of a bang is the reason I've never felt the urge to try it myself.

See the section on "Hydrogen Gassing" on P5 of the document at

http://www.gasman.fsbusiness.co.uk/images/sentinel_product_selection_guide.pdf

Sentinel is one of the biggest UK water treatment chemical suppliers.

Eric Taylor_37

Good Point

I forgot that the oxygen would be consumed right away because of the iron. Copper plating the inside of you iron radiator or boiler? I wonder if that is a good thing or a bad thing.

Eric