Noisy pump, maintenance, add filter?, what's in the water?

MrScott

Hi!  I'm a homeowner with a hydronic system that I don't think was maintained for several years.  Wondering what needs to be on the maintenance schedule? 

 - Would you put in a filter? Water is black.

 - Would you add corrosion inhibitors? I don't know what is in the system now.  Soft water here.

Will have a contractor clean and maintain the boiler this week.  

I want to understand the system better; fix what I can, avoid the more expensive uninformed mistakes (and not try to fix what I can't), accurately report symptoms, and understand what the HVAC contractor is saying for the rest.  I have an (electronics) engineering background.

What should I be doing for maintenance?  

Some of the equipment:
Buderus GB 142-24 propane-fired boiler.
Buderus ST300 storage tank.
Grundfos circulation pumps (UPS15-58 FC/LC at boiler circulation loop, UP26-64 F circulates tank to boiler).

Thank you!
Scott

MrScott

* Replacing the sacrificial anode in the storage tank.  I'll be surprised if there's anything left of the previous one...