If you searched Barnacle Buster, you would probably find a few posts from me regarding my recent use of the stuff. Something from one of the posts:
I have a Dometic 8k btu unit and an oversized March pump. It is about five years old, but not many hours and was getting the hpf error and shutting down. I talked to a couple of techs and they said what is probably happening is that the cooling
coils either have silt in them or a buildup in the coils. That would reduce the heat transfer and trigger the hpf.
First recommendation was to remove the hoses in and out, hookup a garden hose to it, and see if any silt could be washed out with the hose. That didn't yield much, and still got the alarm
. Next thing recommended and tried was Barnacle Buster solution circulated into the coils. I mixed some up in a bucket and used a plunger pump to pull it into the coil. Directions say let sit for 12 hrs, or either circulate. I did not have a circulating pump, so let sit. After about three hours I pumped new solution thru which kicked out the old stuff. Dark black fluid came out with some solids. Let it sit the balance of the 12 hrs, then circulated new solution thru (I had extra in the bucket, and was just pulling that thru). What came out looked like clean solution, so most of the dissolve work was done in the first few hours.
Hooked everything back up and ran it. Cooled much faster than before, plus did not hpf alarm
. I have put another 20-30 hrs run time on it, and it cools down much faster than before, and still no hpf alarm
Someone posted that Barnacle Buster is a phosphoric acid. I don't know for sure. It had some fumes, but less than bromide tablets (which I used to use to keep the green out of the strainer, but Dometic now recommends against that.) It's not cheap
, but it worked well. And I have seen some videos of people using vinegar on scale in head
pipes, and it did nothing.