Background: On demand hot water is pumped through twenty condo units. Also, each unit has a forced air hot water heating element. The outdoor pump is loud and wears out frequently. The noise and vibration travels up the pipe into the floor of the first unit. The pipes make a lot of noise in the unit.

Question: Is the pump under powered? Has eighteen years of mineral build up in the pipes and heating units caused a problem? What can be done to quiet the noise in the unit?

Background: On demand hot water is pumped through twenty condo units. Also, each unit has a forced air hot water heating element. The outdoor pump is loud and wears out frequently. The noise and vibration travels up the pipe into the floor of the first unit. The pipes make a lot of noise in the unit.

Question: Is the pump under powered? Has eighteen years of mineral build up in the pipes and heating units caused a problem? What can be done to quiet the noise in the unit?
It is a closed system mineral should not built up too much . Does it sit on any kind of vibration pad

I just want to clarify, this is a hydronic heating system correct? From what I know of hydronic heating, this could be several things.

It is not out of the question for the heating coils to become clogged, which would need to be acid washed out (I really recommend a hydronic contractor doing this). But caibuadday is correct in that a hydronic heating system is a closed system (or should be), and once the water has been added to the system, corrosion and mineral build-up are not significant, unless a lot of make-up water has to be added (because of a leak). The coils are most prone to clogging because the passages are smaller.

The issue of the pump noise is a little trickier. As mentioned above, it could be mounted directly to the concrete, instead of through rubber isolators. It could also be quieted by using pump isolators, as related in this story: http://www.hpac.com/member/archive/0009war.htm#noise . It could be cavitation in the pump (air coming out of suspension to form bubbles), which can also ruin the pump. It could be a bad bearing in the pump. It could also be that the pipe is rubbing against the floor & framing of the first unit.

If the pump wasn't underpowered when the system was designed and installed, I sincerely doubt it is now.