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Hot water baseboard system flushing on new install?

dough041 Member Posts: 20
I was planning on replacing my old utica hot water baseboard boiler ( 24 years old ) with a Rinnai mod con boiler.
My question was do you guys think it advisable to do a flush with some type of additive prior to the new install? It is a 3 zone/ 3 circ pump gas hot water baseboard system. Anytime over the years I changed a circulation pump etc its didnt seem the water was dirty?
Or would adding some type “cleaner” just dislodge anything in the old boiler heat exchanger tubing into the baseboard? Thanks for any thoughts…



  • hot_rod
    hot_rod Member Posts: 19,277
    It is always a good idea to run a cleaner if just for any oils, flux, dirt that may go in with the replacement.
    The hydronic cleaners are basically a strong detergent, they should not harm any of the older components.
    Rhomar, Fernox, Adey, Sentinel are some of the brands.

    Also important is that you fill with good water quality. The boiler manual should have a water spec.
    Ph hardness, TDS, chloride levels, for example. A fairly simple test kit would determine the condition of your water.

    It adds a few steps to the installation to run a cleaner, flush, add good water, and maybe a conditioner also. There are easy to use aerosol cans for injecting cleaner and treatments. I think the work in systems up to 35 gallons.

    Here is an example of some fluid requirement, from boiler manuals, and an example of a comprehensive water lab report for a problem system. Also some chemical options for cleaning.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream