8 August 2023

I was reading about boilers gas valves being blocked with a black dust called Copper Sulphide (Cu₂S), although I have not experienced this with my previous boiler, I thought as my boiler is new, now is the perfect time to get a Sulphidation filter installed, this was installed close as possible to the boilers gas inlet valve, the filter was a 3/4″ bore version purchased from BES.

The filter simply comprises of a brass body containing a 50 micron (300 mesh) stainless steel sieve which enables gas to flow, but captures particulates larger than the sieve size.

The body of the filter can be separated to clean the sieve, the sealing ‘O’ ring is made from Nitrile Rubber and is a type BS215 ‘O’ ring.

The Sulphidation process can not be stopped as natural gas contains varying amounts of Hydrogen Sulphide (H₂S) and this reacts with the Copper (Cu) pipe, (iron pipes are also affected as a point of interest), as the reaction is within the pipe, the filter must be close to the appliance.

A filter downstream of the appliance, for example directly after the gas meter, will be ineffective.

Installed Sulphidation filter directly below the gas inlet valve to the boiler, a butterfly, full bore, gas isolation valve was also fitted for future filter maintenance.

Hopefully this additional step will reduce the likelihood of premature boiler failure.