Strange smell coming through Floorboards

Hi everyone,

We have a slight problem with a smell in the house when the heating is On.

We seem to be getting a strong smell emitting from the ceiling in our utility room near the boiler and consumer unit which are situated side by side with one another. When the heating is On and has been running for some time (3hrs +), we start to get a smell from a hole in the ceiling just above the consumer unit that fills the room and kitchen all the way to the living room. This is surly and not from the boiler as it can be smelt in the room above.

We lifted the floor boards in the bedroom thats above the utility room, directly above the Consumer unit and the smell was Very Strong. A sniff test (not advisable and not accurate) lead me to two spots where the C.Heating copper pipes seat over the joists just above the hole in the ceiling downstairs.

It is hard to describe the smell, but its not gas or electrical, I would put it close to bakelite but there were no plastic items near the pipes. The heating works fine and this smell only began three days ago.

has anyone come across such a problem? Any ideas what it could be?