"HP" error on heat/AC unit

RVM

Member
Sep 28, 2020
36
Boat Info
2017 Sea Ray 350 Sundancer
Engines
8.2L Mag ETC x2
Hi everyone,

We have a 2017 350 Sundancer with the heat/ac system. The unit has been somewhat sporadic, but was working overall until last night. The heat came on and got up to about 66 degrees and then wouldn't go any higher. There was a steady discharge water flow while working. When I tried to turn it on this morning, neither the heat, nor AC will work and the unit flashes the "HP" (high pressure) code. There is now no water coming out of the discharge either.

Any thoughts on what to do here (if simple) will be much appreciated. If not simple, thoughts are still appreciated. :)
 
HP is usually low water flow. Clean strainers and flush lines. Search this site, there will be a lot of info on how to do this.
 
Also where are you boating, some units are finicky about water temp in the heat mode. But flush system, and clean air screen and coils.
 
Blockage or pump failed, either strainer full of junk, inlet blocked (sucked up bag), growth in the coil or your pump took a dump. Start with the pump breaker and make sure it has power to the pump and then strainer from there.
 
Blockage or pump failed, either strainer full of junk, inlet blocked (sucked up bag), growth in the coil or your pump took a dump. Start with the pump breaker and make sure it has power to the pump and then strainer from there.

This may be a dumb question, but where would I find the pump breaker? Also, I intend to try cleaning the strainer today. There are 2 thru-hull valves in the engine compartment. One is for the generator and the other goes toward the front of the boat to "some unknown land". Presumably, this is for the AC unit :)
 
I would agree that the one going forward is probably for the AC pump....but why not get on your hands and knees and follow it to be sure? I would also add that the prime in the AC pump is easily lost. So, essentially the pump may be on but no water is flowing through the AC line(s).
 
Shut the A/C breaker off to reset everything before you try to restart the system.
 
Thanks everyone. The strainer is cleaned and there is flow to it. No change. Any ideas?
 
Thanks everyone. The strainer is cleaned and there is flow to it. No change. Any ideas?
is the pump running? is there power to the pump? I would go to the unit and remove the inlet line and rig up a hose to it to force water through it and make sure there is no blockage. Have you ever flushed this unit before with barnacle buster? Are you in Saltwater or fresh?
 
is the pump running? is there power to the pump? I would go to the unit and remove the inlet line and rig up a hose to it to force water through it and make sure there is no blockage. Have you ever flushed this unit before with barnacle buster? Are you in Saltwater or fresh?

The pump isn't running, but I am not sure if the error code is stopping it. Would this be the case? Bought boat in Sept. so I have not flushed anything. In Saltwater. Much appreciated.
 
Ok so pump is automatically triggered from the AC unit relay system. If you reset everything does it try and run for a minute before the HP error comes on?
 
Ok so pump is automatically triggered from the AC unit relay system. If you reset everything does it try and run for a minute before the HP error comes on?

When I turn the breaker back on there is power to the panel. The fan will run in dehumidifier mode, but as soon as set to heat or cool the "HP" error comes on immediately
 
Well... could be a compressor or bad HP switch if that is happening that fast. Usually they will run for a minute or 2 before going HP after getting hot. Without getting into using a meter or gauges to diagnose, I would still remove the inlet cooling hose on the unit and hook up the garden hose and force water through it to make sure it is not blocked. If that is flowing then you will need pressure gauges to see what is going on. Where are you located?
 
High pressure in heating mode means restricted air flow. High pressure in cooling mode means restricted water flow. It’s sounds like a bad hp pressure switch, a broken wire going to hp pressure switch or a bad circuit board. You can pull the wires off of the pressure switch and tie them together and see what that does.
 
High pressure in heating mode means restricted air flow. High pressure in cooling mode means restricted water flow. It’s sounds like a bad hp pressure switch, a broken wire going to hp pressure switch or a bad circuit board. You can pull the wires off of the pressure switch and tie them together and see what that does.
this^^^^
 
Did you happen to check the filter that covers the air return on the front of the unit. I was having performance issues with the unit and found this...

20201201_173346146_iOS (2).jpg


Removed the filter, temporarily, and ran the heater and it performed great.
 
Did you happen to check the filter that covers the air return on the front of the unit. I was having performance issues with the unit and found this...

View attachment 95752

Removed the filter, temporarily, and ran the heater and it performed great.

I can't even find where the unit is.....its ridiculous.
 
If you don’t know where the unit is then filter has never been cleaned. Here’s hoping that’s all it is. Look under the bed.
 
If you don’t know where the unit is then filter has never been cleaned. Here’s hoping that’s all it is. Look under the bed.

We bought it in Sept., so I am unsure if it was done before...but I doubt it. I looked, but the only places it could be were "screwed down" and I wasn't sure why that would be the case so I didn't take everything apart.

Maybe I should get the screwdriver back out. haha
 
91511441-DCB1-44CD-8089-A8C194F129B3.jpeg
We bought it in Sept., so I am unsure if it was done before...but I doubt it. I looked, but the only places it could be were "screwed down" and I wasn't sure why that would be the case so I didn't take everything apart.

Maybe I should get the screwdriver back out. haha
I found this online. Looks like it’s in port aft corner of the cabin.
 
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