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Stupid A/C Chiller System Question

Discussion in 'HVAC' started by DOCKMASTER, Jun 29, 2021.

  1. rtrafford

    rtrafford Senior Member

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    But big condensation? Just curious as it seems they'd sweat a lot...
  2. Pascal

    Pascal Senior Member

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    Maybe a little more but that’s not an issue as unlike the flat bottomed alum drain pans on cruisair units, flagship uses tilted stainless steel pans so they drain very well.
  3. mapism

    mapism Senior Member

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    Well, actually in all chiller units I'm aware of (though most of the ones I've seen were built by Condaria, before the company was taken over by Dometic), also the circulation water volume doesn't depend on the number of compressors running.
    In fact, I've always seen a single circulation pump, that runs constantly as soon as the system is turned on, regardless of compressor(s) cycling on and off when the preset temp is reached.

    But coming to think of it, a dedicated circulation pump for each compressor could be a nice redundancy, so maybe some other manufacturers might have gone that way, IDK.
  4. rtrafford

    rtrafford Senior Member

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    I agree....those pans are such an easy design to get right, yet everyone seems to get them wrong. Even my Techicolds. Drains are around back, very difficult to reach, keep clean. I built a jig to clear the drains, one on each side, neither convenient.
  5. rtrafford

    rtrafford Senior Member

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    Yes, single circulation pump running constantly on its own circuit. Better to keep that fluid moving than to start and stop with the compressor. Setting up with two pumps and an A/B switch is easy, and you could alternate between the two. That's how my raw side is plumbed....an A/B switch that the compressors call to the switch, and I can direct them to the pump I choose to exercise.
  6. mapism

    mapism Senior Member

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    Nice setup. I guess you could do the same also with the cooling liquid circulation pump, hence getting a full pump redundancy.

    If airco would be absolutely essential in my cruising area, I would consider modifying my system in the same way.
    But luckily, most of the time just keeping side windows and portholes open to let a bit of breeze inside is enough - and actually preferable to stay shut inside.
    We do have some odd hot and humid days, but even then, it wouldn't be a huge issue to live with no airco for one day or two, waiting for a pump to be replaced...
  7. Pascal

    Pascal Senior Member

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    It also depends on the boat. Older boats had pretty good ventilation but nearly all modern boats have zero air flowing thru

    Circulation pumps should last a lot longer than the raw water pumps. It can be replaced pretty quickly as long as you have isolation valves at the inlet and outlet. it s nice to have the spare ready to go like we have with the raw water pump but it s not always feasible.
  8. mapism

    mapism Senior Member

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    Spot on.
    I always thought that glued glasses are a major example of regress in boatbuilding.
    Only good for two things: cutting production costs, and allow a sleeker design.
    But a design where form does NOT follow function! :confused:
  9. Capt J

    Capt J Senior Member

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    This is true, BUT opening windows were and are always a source of water leaks on yachts.
  10. Pascal

    Pascal Senior Member

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    And this is why the redundancy of chillers is so nice. Loose the salon remote condenser and you re going home. Loose one chiller, and while warmer the salon will be usable especially if you set the lower staterooms higher during the day.
  11. Capt J

    Capt J Senior Member

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    Yes and no. Lose the circulation pump, trigger board, or blow a circulation hose and you're out of A/C to the entire boat. Also you're stuck with either A/C or heat for the entire boat. Also if you just want 2 units on because you have very limited shorepower, and can't support a 5 ton chiller popping on and off........ Generally a salon has multiple A/C's....... I prefer the redundancy of package units or split units under 70'. Only thing they have in common is a seawater pump.
  12. Pascal

    Pascal Senior Member

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    A circulation pump can be replaced in 30 minutes... if you low a hose in the loop you can usually isolate that section. Loose a trigger and you can hard wire the pump.

    what scares me on cruisair is loosing the control board... but that s a design flaw.

    I ve never had the need for heat and air con at the same time.

    At docks with limited power, I find easier to manage the load with chillers than splits.

    day before yesterday, one the chillers on my own 53 popped high pressure. Didn’t have a chance to clean the line yesterday and will probably get to it today... no problem. It s a couple of degree warmer inside today but comfortable. If it had been the master split clogging up, it would have been kicked out of bed to fix it :)

    4 years with the chillers on my personal 53 and I love them
  13. rtrafford

    rtrafford Senior Member

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    Agreed, the circulation pump is very often much easier and comfortable to access. But in my mind it does need to run continuously as while the chilled loop will reach its goal temperature allowing the compressor to shut down, the air handlers may still be in the process fo cooling their rooms and need the water flow. So, if you install redundant loop pumps, use an A/B switch and periodically change pump to share the load.
  14. rtrafford

    rtrafford Senior Member

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    Yes, I can see the need in certain climates and with someone aboard that doesn't tolerate cold very well. In this situation we'd be well served to have a heating element in the air handler in the staterooms whereby the air handler can use the electric heat, not call the water, and warm the room. That's Technicold's typical setup. I went pure cold with separate inline heating elements for the loop. Those work very much like an instant hot for hot water, but they can be set to turn off at your desired temp, and those, too, can be staggered to help handle the load. This spring we used the heat at night (just one element was required), and then shifted back to chillers in the daytime as needed. With a metal boat that 59 degree sea water transfers pretty efficiently inside...
  15. mapism

    mapism Senior Member

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    +1, best thing since sliced bread.
    BTW, I used to have split units in my previous boat, and from the noise viewpoint there's no comparison.
    From inside the boat, I literally can't tell by ear when the chiller compressors in the lazarette astern are cycling on and off.
  16. rtrafford

    rtrafford Senior Member

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    My Technicold chilled water air handlers have an option for a heat strip to be added to any air handler. The control will call for that heat strip in a cabin if needed, and it will bypass the heat strip and return to the looped water if it sense the water temp to be warm enough.
  17. wdrzal

    wdrzal Senior Member

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    Heat wise I would scavenge as much as possible from your engines and generators. Then install a electric furnace . They are small, hang from the wall are 99% efficient and completely quit . Sure generator has to run, but biggest plus is no additional exhaust to deal with.
    Last edited: Jul 6, 2021
  18. DOCKMASTER

    DOCKMASTER Senior Member

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    So we had some time on our hands so I asked my guy to troubleshoot why the port side air handler in the master stateroom wasn't working when I was using the A/C last time. So he pokes around a bit and in the process of getting ready to pull the access cover in the hanging locker to get to the air handler he finds a switch in the back of the locker. It looks like a typical light switch except it's labeled Port AC on the on side and Vent on the off side. He flips to on or Port AC , and walla - the air handler kicks on. So my stupid question of the day is. why would this switch exist? It doesn't appear to be original. I have no idea what it means by Vent or if that's just the way it's labeled. Anyone offer a clue or suggestion here?

    AC S witch.jpg
  19. Donzi 54

    Donzi 54 Member

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    That's not part of our system. Have you verified that the air handler is tied into the chiller loop. It may have been bypassed because of a leak.
  20. mapism

    mapism Senior Member

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    I suspect that the switch is just on/off, and whoever fitted it didn't think that it would have been more logical to attach the label "Port AC vent" on the "on" side, rather than splitting it.

    Ref. the reason, I can't read the mind of Mr.retrofitter of course, but in my boat all cabins have a switch near the beds that allows to switch off the air handler vents regardless of whether they should be on or off depending on the thermostat controlling them.
    That's an OEM arrangement, arguably unnecessary, but I always guessed that the idea was to allow anyone to turn off the air handler without jumping out of bed to change the thermostat setting.