Strained Air Conditioner Relationships

Cool Box and Air Conditioner  Strainers

Coming home after a recent thunderstorm and finding the air conditioner panel showing an error code of "HI PS", it was somewhat natural to assume a high power surge had tripped the unit and resulted in Cassie's air temperature rising to 84 degrees F which was less than desirable. Pressing the start button brought the unit back to life and it appeared to run fine through the evening.  Awakening to a tripped unit and the same error code the next morning made us think again. While the unit ran fine through the day, a review of Cruiseaire error codes enlightened us that "HI P5" indicates low cooling water flow and recommendations to check the strainer.

Having somewhat traced the cooling line to a couple strainers conveniently accessible through a removable floor panel and finding one of them thoroughly fouled, we really thought we had solved the problem only to be disappointed to see only the same weak flow of water outside after the effort.  And yes, the previous owner had tied the needed wrench right next to the strainers. And no, I won't tell you how long I wrestled with the tops and various other tools prior to looking closer for the wrench after convincing myself that the guy had to have stored the wrench where it was needed.

The following evening, I disconnected several sections of hose, blew through them and/or ran coat hanger wire down them, but saw little if any improvement.  The next evening, I followed recommendations to disconnect each section of hose and run pressurized dock water through them which seemed to confirm each section of line was open as well as the unit given I blasted water through it as well as its exit flow line to the hull penetration. The flow improved for a short time and then slowed again and I awoke to the same "HI PS" trip code.

Having opened the pump and cleaned it, I called Dometic and learned the pumps were rarely an issue and that I should try pumping overboard or to the sink to prove out the pump before replacing it.

As it turned out, all I needed to do was spend $$ on a new length of hose and attempt to install it. My son's heavier handed approach to the elbow fittings on the seacock resulted in our removing the elbow and discovering a plastic wrapper within it - labeled with the word "NICER" on it which got a chuckle given there was nothing "nice" about the previous evenings of hose removals and testings.

With a new section of stout hose between the seacock elbow and the strainer, water flowed full force once again from the air conditioner to the sea.  Of course the other side of the seacock elbow servicing the cool box no longer flowed resulting in us changing out its first short section of hose also to get it flowing again.  The remaining purchased hose will make for a nice spare should it ever be needed and you would not believe how much better the air conditioning unit is working now !