Boiler plumber recommendation!

Many homeowners start to check up heating and boiler condition. I am one of them. Here is my situation. I and my husband had quite big renovation including extended room with new additional heating system (hot water and base board)in this year. The renovation started from March 2008. It was great heating condition in early 2008. After our renovation, there is inproper heating. Whole rental 3rd floor has no heat rooms and our 1st floor has heat, but no heat in bedroom. Then our contractors say that annual water change/water pressure for heating is needed, it costs $800. Homeowners!! how often do you maintain your heating boiler and do you need to do annual water change/pressure?
If so, how much does it cost? Please recommned us your good boiler plumber! Thank you for your reading this!!
Best,

By momo |