Galvanic Corrosion Concern
Galvanic Corrosion Concern
(OP)
We have a project with York air-handling units with chilled water cooling coils that have copper tubes, copper tube headers and steel pipe nipples for connecting the coil header to the building chilled water supply and return system.
We've challenged York about the galvanic coupling in their coil design and they've responded that since they braze the steel nipples to the copper coil header with silver alloy which is more noble than either copper or steel, they say it acts as a dielectric metal between the copper and steel.
I've never heard of using a conductive metal as a dielectric material.
Any comments?
We've challenged York about the galvanic coupling in their coil design and they've responded that since they braze the steel nipples to the copper coil header with silver alloy which is more noble than either copper or steel, they say it acts as a dielectric metal between the copper and steel.
I've never heard of using a conductive metal as a dielectric material.
Any comments?





RE: Galvanic Corrosion Concern
If the connection between the two metals is electrically conductive, and if the corrosive medium can simultaneously coat both metals, the less noble will corrode.
RE: Galvanic Corrosion Concern
RE: Galvanic Corrosion Concern
RE: Galvanic Corrosion Concern
Silver braze will not work the way they're describing.
If the chilled water system is closed loop with only infrequent make-up, it might last for a very long time due to the very limited quantity of oxygen. But if the cooling water is open loop or in contact with the atmosphere anywhere, you will lose the carbon steel material over time.
RE: Galvanic Corrosion Concern
RE: Galvanic Corrosion Concern
rmw