Kirk (Gallivanters) describes the generally accepted method of cleaning
Condensers & Heat Exchangers.
I might add that a “spare AC pump” isn’t necessary. Since most Air-Conditioners need on the order of 200GPM of cooling
water per Ton (12,000BTUH) of capacity, a cheap bilge pump
(500GPH) could do the job.
air conditioner raw water
systems are typically manufactured from copper alloys, and lead/tin or silver solder. These materials are not generally harmed by proper cleaning with appropriate strength acid/water solutions, for limited amounts of time. Many Marine Air-Condittioner manufacturers sell cleaning solutions which are appropriate for their particular systems, and provide recommendations for using their cleaning agents, which are often acid/water solutions. If you have concerns about proceeding on your own, I suggest contacting the system manufacturer for guidance regarding your particular model air-conditioner.
* I believe that Cruise-Air (Dometic) recommends a 5% Muriatic or Hydrochloric acid/water cleaning solution, followed by a freshwater flush.
If the Heat Exchanger
, it would likely be severely damaged by using ANY kind of acid-based cleaning solution.