Recomissioning Radiant Heatinr System
I’m ready to refill my radiators & heater (hot water, not steam) after making some changes:
– Removed 4 radiators to make remodeling a kitchen and a couple of other rooms easier
2- Tied in a coil in my new air handler – we installed central air and decided to use the water heater instead of buying a furnace
Other than checking for leaks as I fill the system, what are some precautions that I should take? Any treatment chemicals needed?
The system has been sitting empty and open for several months. I took the opportunity to install a backflow preventer on the fill line, and I used PEX to transition from the iron pipe system to the copper coil to prevent corrosion.
As a side note, the PEX coupling was brass, so I ended up having to get a bimetallic union to go from iron to brass before hitting the PEX. Was this necessary? I guess that the PEX was no longer necessary in this case, but it is much easier to route than copper.
Thanks-
Lew
Replies
In large commercial jobs where the heating piping was opened and modified, I would specify that the piping system be filled, flushed and chemically treated to remove all cutting oil, deposits, metal filings, etc, and to "passivate" the inside of the piping to arrest corrosion.
In your case, I would at least hook up a hose and flush it completely until the discharge is clear and clean. Opening up a system with steel/iron components creates a lot of surface rust and may dislodge deposits of corrosion products from years past. Fill it, vent it, get it closed and up to temperature and let the air separator work. I would not fill it until you are able to apply heat and run the system for an hour or so.
Thanks Tim - the passivation is what I was thinking of. Do you know of any such products available to consumers?
The company with which I have the most familiarity is Great Lakes Treatment Corporation, and their products are available nationally. What is recommended for your application is their product #5937. It is a phosphonate, witha polymer additive and a surfactant. What that means in english is that is a cleaner/corrosion inhibitor (the phosphonate part) that will keep solids in suspension (the polymer portion) so they can be flushed/filtered out and the surfactant will dissolve and remove any oils in the system. 5 gallons should treat your system. The cost is a little steep about $400 including shipping.
There is also a product called "Boiler Guard" and sold through Diversitech, which means it should be available at most HVAC supply houses. 1 gallon lists for $43.40, 5 gal. for $217.00.
Edited 8/31/2005 1:01 pm ET by Tim