Clean those Air Conditioning lines out - Public Service message

Boat Guy

Boat Guy

Well-Known Member
May 15, 2013
2,289
Who knows? Could be Cali, Oahu, Florida, Annapolis
Boat Info
400 DA
Engines
CAT 3116s
So, I noticed that the water was just a trickle coming from the bow thru-hull.... I figured that wasn't good so I should probably check the strainer, etc... Well, the next day I had AC failure, HI PS and it stopped working...So much for procrastinating...haha

But I figured since I had good flow to the aft unit, I would still have that unit to keep things cool...Well, that went to HI PS shut down also.. So much for redundancy. I like having two of things, but when they have common components, that whole redundancy is a bit of false security.

Fortunately, I understood the system pretty well and had just cleaned the strainer about 10 days earlier... I should say I cleaned the bowl too. The strainer was filled with biomass and so was the glass bowl. So I cleaned the strainer and flooded the bowl with fresh water and cleaned it as well.

My system has on inlet thru-hull leading to one strainer bowl that the leads to the single pump that has one outlet with a "kindof" Y fitting allowing for two hoses to be connected. One hose to the aft unit and one to the bow unit.

To figure out where the clog was I started in the bilge and after closing the thru-hull valve, I unclamped the hoses and cleaned them. Because they were so short I could visually see they were clean... In fairness, I knew which line was likely to be the issue... But since the aft unit showed "HI PS" I wanted to be sure to investigate them all...

I was unable to clear the main culprit, the hose going to the bow unit, from the bilge. It would just spray water out from the makeshift connection. So I took the water hose from the dock up to the opening at the bow unit and flushed it back towards the bilge. That did the trick, and all the biomass came out. Probably as much as was in the strainer. I picked it out of the bilge water so it wouldn't have to be forced out of the bilge pump....

Lesson learned...

Still interested why the "HI PS" would stop the aft unit with good flow. Anyone know where the sensor is or what it's actually doing?
 
Used the reverse flow technique successfully a couple of weeks ago. Our water is warmer than usual so growth has been worse too.

MM
 
I put a "T" connector on my hose with a clip-on hose connector and shutoff valve. Just pop the hose on, turn the shutoff valve, and let the dock water hose clear the lines. I do clean the strainers almost every week or two.
 
Good idea...

I think I will incorporate something like what you've done...

I was working on solving the problem that night after coming back from seeing a friend. So I started at 10PM...The advantage was that it was cool...Wanted to solve it with what I had aboard. Got creative and lucky I saved a piece of hose from the genie that I was able to cut into a 7" sleeve. It fit perfectly over the AC hose and around the dock water nozzle as a coupling...It saved me from spraying water everywhere and I had the A/C operational in about 3 hrs.
 
Eric,

The HI PS is telling you nothing more than the compressor head pressure is too high. That almost always comes from the compressor getting hot which causes the internal pressure to be high. Several things impact that…….inadequate cooling water flow, high ambient temperatures, a hot bilge or a faulty pressure switch on the compressor head.

here in Florida, we generally run acid thru the system in the late summer to prevent/eliminate cooling issues. It is a lot easier than trying to clean up clogged lines.
 
Thanks Frank,

What I found very interesting is both units gave me the "HI PS" indication and shut off even though the water flow to the aft unit was real good... The only variable that changed was a clogged hose to the bow unit which I think would cause more water flow to the aft unit and increase it's cooling cap.. Both units worked great and are still working fine with no issues after I cleared the one hose going to the bow unit.

The day in question was the one day that week that was mild, mid 80's..And the night was cool. So the bilge was cool and the ambient temp. was fine... I did try the unit when I got back to the boat around 10pm to see if they would run and I got the "HI PS" shut down on both (running individually - I never run both units at the same time)


To me, that's confusing.

BTW - I'm so thankful it failed when it did and was cool that night...The positive out of a not so great situation.
 
fwebster said:
Eric,

The HI PS is telling you nothing more than the compressor head pressure is too high. That almost always comes from the compressor getting hot which causes the internal pressure to be high. Several things impact that…….inadequate cooling water flow, high ambient temperatures, a hot bilge or a faulty pressure switch on the compressor head.

here in Florida, we generally run acid thru the system in the late summer to prevent/eliminate cooling issues. It is a lot easier than trying to clean up clogged lines.
Click to expand...

Frank,
What kind of acid and do you dilute it? And how do you run it thru.. backwards, or from the sea water pick up.

As for the strainer, I've had times I've had to do it daily. We have a lot of junk in the warm waters of FL this time of year.
 
fwebster said:
Eric,

The HI PS is telling you nothing more than the compressor head pressure is too high. That almost always comes from the compressor getting hot which causes the internal pressure to be high. Several things impact that…….inadequate cooling water flow, high ambient temperatures, a hot bilge or a faulty pressure switch on the compressor head.

here in Florida, we generally run acid thru the system in the late summer to prevent/eliminate cooling issues. It is a lot easier than trying to clean up clogged lines.
Click to expand...

# 2 on this I do it 2 times in the summer.
 
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