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Thread: Cruisair help

  1. #1

    Cruisair help

    Working on the master stateroom A/C - 12,000 btu. The unit hasn't been cooling as well lately, so I set about to do the annual adding of a small amount of R-22. At this time, it's only cooling the air 17 deg. According to the charging curves in the installation & operation guide, I should be seeing around 62 psi on the suction and 175 psi on the discharge with the air & water temps we have. Seeing 58-59 on the suction and 230 on the discharge, superheat is between 11 and 12 deg, and the subcool 10-11 deg. Temps are cooling down here, 74 deg inside air temp and 67 deg water temp so I can understand the lower superheat numbers, but why am I running such a high head pressure? Restriction in the line? The air handler is clean. When put into heat mode, it blows some warm air for a short time until the compressor kicks off. The high side line, which should now be the suction when reversing is way too hot to touch. After running 20 -30 minutes cooling, the compressor starts to ice up. The air handler is not icing up. I haven't measured pressures when heating yet.

    Does anyone have any ideas what I should look for?


  2. #2

    Re: Cruisair help

    Not getting rid of the heat. Clean the condenser.....Pat

  3. #3

    Re: Cruisair help

    And in heat mode not picking up heat from the water

  4. #4

    Re: Cruisair help

    Sorry about multiple posts but canít edit from iPhone , so water flow could be issue also or dirty condenser / heat exchanger.Check water flow and strainer first.

  5. #5

    Re: Cruisair help

    Thanks Pat. I have not cleaned the condenser since we've had the boat. It's one of 5 units all fed by the same pump, the rest are working fine & good water flow so I didn't think about that. There could be a restriction in that condenser, especially since we went from saltwater to freshwater. I'll rig up the plumbing to backflush the system. Is everyone still recommending phosphoric acid diluted or do I go with barnacle buster?


  6. #6

    Re: Cruisair help

    I used ospho last time but do not remember the dilution . Although I think it was 1 acid to three water.....Pat

  7. #7

    Re: Cruisair help

    Thanks again Pat, I will give that a try

  8. #8

    Re: Cruisair help

    BB is phosphoric. 1:4 for motors. Iím a bit leery of that in HVAC. Iíd go 1:5 or 6.
    Semper Siesta
    Robert Clarkson
    ASLAN, 1983 55C #343
    Charleston, SC

  9. #9

    Re: Cruisair help

    One of my Two chillers threw a high pressure error yesterday even though i descaled it 6 months ago. The other one was fine so I turn off the valve at the manifold. Pulled the hoses and they were clear. Blowing thru the coil there was something in there that even dockside water pressure would not flush out. I broke the bucket and pump and 4:1 barnacle buster. Descaled for 45 minutes and all good now.
    Miami, FL
    1970 53 MY #325 Cummins 6CTAs
    2014 26' gaff rigged sloop
    2007 Sandbarhopper 13
    12' Westphal Cat boat

  10. #10

    Re: Cruisair help

    Definitely sounds like that's what I need to do. Robert, I will go with the 1:6 ratio. I'd rather play it safe. I'll let everyone know the results.

    Thanks guys,


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