Ac shut down w P5 message

[Flytrade]

I’m on a trip and my AC just shut down and it says hi P5. What is that, how can I fix it? It’s starting to get hot. Please help

 

[TNT8808]

hi P5 means Hi Pressure. You'll need to at minimum close your sea cock, and clean out your strainer and possibly also blow out your white water lines after the strainer with a water hose if that doesn't fix it. Some do that from outside the boat, and I do it from inside the bilge. Most likely others will chime in as this is a common issue.

-Tom

 

[Flytrade]

Thanks. I’ll try that right now.

 

[Flytrade]

The strainer has a plastic cap. How do I take it off?

 

[Flytrade]

I got it off by unscrewing.

 

[Flytrade]

The air-conditioner is working, but only about 1/3 of the normal flow of water is coming out of the boat. I clean the sea strainer and then disconnected the line at the pump. I backflush that line, then sucked water into my mouth, and the line appears to be clear. I then disconnected the White hose going from the pump to the AC unit. I put a hose to it and the water flowed freely. I then connected everything back up and I’m getting about 1/3 water flow out of the boat. The pump sounds to be operating normally, so I’m thinking it may be the impeller. Your thoughts.

 

[Southern Cross]

Did you clear the line running from the A/C unit to the discharge port in the hull? Sometimes that gets clogged (mud dauber nest) and may result in the P5 code.

 

[TNT8808]

Since you said water flowed freely out the discharge when you connected a hose to the white A/C hose after the pump my guess is you still have something on or in your intake under the boat.

 

[fwebster]

This is why it is so important to have full information in your posts or in your header. We don't know if your boat is in salt or fresh water. If you are in salt water or if the cooling system has not been cleaned, it could well be clogged with barnacles, sea worms, slime etc. The HI-PS trouble code is usually caused by high compressor head temperature due inadequate cooling water flow......either from inadequate volume entering the system or inadequate heat exchange due to inadequate seawater flowing through the cooling coils.

So, are you in salt water?

 

[Flytrade]

Thanks for all your replies and help. Yes I am in salt water and I backflushed the line from the pump to the seacock and it appears to be clear. I can also, with my mouth, suck salt water through the line. I then disconnected the white line going to the air-conditioner and flushed it out with water, and water is exiting the boat as it should. That told me the problem is in the pump. I then connected a garden hose to the white hose going to the air-conditioner unit in the system works fine. Now I just need to get someone to replace the pump. Thanks again for all your help.

 

[GCHOG]

having the same problem this week also , however, my Dometic water circulating pump quit pumping . The pump would just hummm. Took it apart, (removed the intake hose, and the end of the pump housing(4 screws), impeller, and guide pin).Everything looked good, no obvious signs of wear. Wiped all parts , lubed the guide pin, and impeller, put it back together and tested, but the impeller still would not spin. ( I actually did this 3-4 times with no luck). Now, a small back-story, I had the exact same problem last spring and ended up getting a "wet end rebuild kit" from March Pumps. I intstalled the new parts and the pump immediately worked fine. So, I again purhased a new kit this week, just received it yesterday and plan to install tomorrow.
Check and see if your pump just humms when you turn the AC on. If so, its a good posibility you have the same problem. I got the rebuild kit off ebay from Marine Parts Source for $91.99 +shipping. If that is the problem, it really is an easy 30 minute fix. Just make sure what make/model pump you have before you order parts.

 

[JVM225]

Did you clear the line running from the A/C unit to the discharge port in the hull? Sometimes that gets clogged (mud dauber nest) and may result in the P5 code.

Same thing happened to me and mine also worked well when a garden hose was pushing water through there at 40 PSI.
In the end though I had to pull out a dresser that was inside a closet to get to the back of the through hull discharge for my forward unit last year.
Naturally it had to be the one that was harder to get to that was giving me the problem.
But sure enough, when I pulled the hose off of the back of the through hull and shook it out some tiny little shells and other debris came out. Seems that when I flushed forward from the strainer I pushed the junk forward and it got hung up in the very end of the discharge hose where it connects to the back of the through hull.
Cleaned it out and no more problem!
It doesn’t take much to restrict that flow.
When I have the boat pulled at the end of the season I usually winterize the AC units by pumping pink in through the discharges until it comes out the bottom of the boat.
Before I do that I do as Tom said and flush the system backwards through the discharges.
Even with doing that every year I still managed to pick up some crap in there in the middle of last season.

 

[RickC1883]

I had the same issue today after cleaning the sea strainer with it only having 1/3 stream out the thruhull and giving a HI P5 error, it seems I had a bunch of junk in the inlet that made it’s way down the tubing when the sea strainer was removed. I emptied the strainer body of the dirt water by blowing into a tube and letting it go into the bilge. I reinstalled the sea strainer and put in some dawn detergent in the body. Then secured the cover and opened the seacock. When I started the AC I saw a bunch of crap water exiting the hull then full stream again and bubbles in the water and my AC is nice and cold again!!