On 5/7/2014 5:55 PM, Ray wrote:
We live in a six-unit apartment building which is heated by radiators.

The boiler is a commercial, as opposed to residential unit. I understand
these don't last as long as residential systems.

Could anyone share any experience with such boilers?

Ours is nine years old, and already the large copper conduits are
showing signs of corrosion in the joints, suggesting leaks.

Can this be repaired rather than replaced?

It should last much longer than 9 years. Maybe 50 or so with care. The
copper pipes are not part of the boiler but are just the feed or outlet.
They often show some corrosion at fluxed joints. Try cleaning the joints.

You don't say what type of boiler so I can't give specifics. Most can
be repaired by re-tubing or replacing sections.