I have a relatively large system, 5 zones, some are pretty long runs. Mostly PEX tubing through the attic with copper base board radiators. System was installed in the early 90's but the boiler was changed last year. I'm not sure how completely the installers purged and cleaned the system and my water is VERY hard. I want to clean and purge the system so I can be sure the system will be all set for a few years. So is it as simple as attaching hoses to each connector on either side of a particular zone pump, putting the fill hose into a container of Noburst 100, putting the drain hose in the sink, and running the zone pump until the clean stuff comes through? Then repeat for each zone? I also have an RV transfer pump in case use of the zone pump for this is not recommended. What about cleaning: Noburst has a System Precleaner. You're supposed to fill the system with distilled water, add some of this stuff, run it for a day or so, then totally purge and clean. Could this actually cause problems by activating leaks that may have been plugged by mineral deposits? Could it be bad for PEX? Even if I'm being a bit anal about this I'd rather do it unless it may cause more problems.

Last winter I had a carbon monoxide problem (!!!) and the gas company shut down my boiler and told me the heat exchanger needed to be cleaned. The boiler is old...probably original with the house which was built in 1966. It's gas fired, baseboard hot water - the kind with the little square fins. Don't know the brand. I was out of town at the time, but I called a furnace company to handle the problem. They told me they don't do that type of thing and didn't know who did, but as a courtesy to me they agreed to come and clean the exchanger as best they could. They did, and the CO problem went away. What a bunch of soot they removed!! I want to get it professionally cleaned the proper way but can't seem to locate anyone to do the job. I was told a couple times to just replace the entire system because it's old. Easy for THEM to say...that's a lot of money for a boiler that still works! Any ideas? Who would do that type of thing?