Cleaning A/C Raw Water / Heat Exchanger Lines

[svHyLyte]

This past weekend I started doing the annual maintenance on our reverse cycle 16,000 BTU A/C unit but I came up against something new.

Because our little marina is a few miles up-river of Tampa Bay, there is a good bit of silt in suspension in the water. This normally results in an accumulation of material in the raw water feed lines and heat exchange coil that must be back-flushed out periodically--usually a time consuming but not complicated job. In past I have been able to simply connect up a garden hose to the discharge line and run a temporary line from the in-put side of the coil to a 5 gallon bucket and blast out a substantial amount of debris. Once the water runs clear, I introduce a 10% acid mix to the coil and let that sit for awhile to dissolve any scale that may have built up on the inside of the coil and then rinse that out. The foregoing treatment normally increases raw-water through-put markedly and the system--on heat or cooling--works noticeably better.

Upon removing the in-put lines this past weekend, I discovered the inside surfaces were coated with a thick oily material which I attribute to the fact that we've had a large influx of power boats in our basin and, accordingly, many instances of fuel, oil and/or worse being dumped in the water during the last year. In any case, this coating was difficult to remove from the lines I had in hand, and, in fact, could not be removed until I ran some "Goo-Gone", a Citrus Oil based cleaner, through the lines followed by hot water and then a swab of cotton. Undoubtedly, this coating extends throughout the system and A/C coils, and if not thoroughly removed, may increase the rate of the obstruction of the coils. I am also concerned that this coating will prevent an acid wash reaching the scale and what-not that may have built up on the inside of the coil.

The question is then, what is the best way to remove this coating given that I can’t run a wad of cotton through the entire system. Any suggestions or recommendations will be appreciated.

s/v HyLyte