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Chiller help

Discussion in 'Technical Discussion' started by Seasmaster, Mar 4, 2019.

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  1. Capt Ralph

    Capt Ralph Senior Member

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    It's a BOAT (Bend Over And Take-it).
    New phrase from another great contributor I'm using lately.
  2. Pascal

    Pascal Senior Member

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    I have never used their self contained units so i can’t comment beyond the fact that as you mentioned sometimes it is the installation instead which cause noise and vibration

    I feel that having to manually reset a high pressure switch is a small price to pay for a simple design using simple parts instead of expensive proprietary boards. My chillers have lights to indicate low pressure, high pressure, chilled water flow failure or low chilled water temp. Simple. That s all I need. I don’t need to have to scroll thru menus...

    The off the shelf Tstat give you more flexibility incl programming by day/time and the option to use smart WiFi Tstat if desired. Contrast this with the Cruisair controls (small grey panel with small LCD). Most people need to put reading glasses to use them and the buttons are so small that they often turn them off or switch them to heating mode. Lousy design... i constantly have guests asking why their AC doesn’t work despite having printed easy to read how to laminated cards!

    Over the years I have had to replace so many condensers, air handlers, control boards etc on cruisair equipment... sure they’re a known quantity but they are no longer manufacture the Ole
    Blue stuff that used to keep ticking 20 years later

    It is unacceptable to have to replace 4 out of 15 air handlers on an 8 year old boat. Or 3 condensers under 10 year old
    Last edited: Mar 6, 2019
  3. Seasmaster

    Seasmaster Senior Member

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    BOHICA
    SNAFU
    TARFU
    FUBAR

    That said, I really can get my head wrapped around the new BOAT axiom!! Or, as it was sometimes said, "Embrace the suck!"
  4. Capt Fred

    Capt Fred Senior Member

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    The start issue most likely is aggravated by temperature so when you do the current in rush test the engine room needs to be at temperature. The in rush current will let you know which way to proceed but could be something as simple as a temperamental circuit breaker in the genset.
  5. Seasmaster

    Seasmaster Senior Member

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    Ok Everybody swallow their coffee, beer, wine, or whatever, [I don't want you to spray it out] and check this out.

    The boat has a potable water hose connected from the fresh water pump to the pressure switch on the circulating pump. Although the tech hasn't tested the chill water side, we expect to see only water, not an anti-freeze/glycol mix. The tech guy is more apoplectic than me. . . Me? I'm having a serious WTF moment!! So, I've been running the ac system with that good quality South-Florida & Central Florida drinking water? That might explain some of the corrosion we are seeing on fittings.

    I'm going to put out these flames with some serious grog!! Y'know, it's 17:00hrs somewhere..
  6. captholli

    captholli Senior Member

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    Its a normal plumbing circuit to have chiller loop "make up water" or the vessels pressurized fresh water system plumbed into the chilled water circuit. If the chiller loop was commissioned correctly with Food grade glycol at inception than it will still remain in the chilled water loop unless the system has had a constant leak and make up water was used extensively. The dumbed down systems have a auto regulator on the make up side of the loop and over time the regulator will fail allowing your chilled water loop to over pressurize and blow cruddy loop water all over the place. Murphys law...
  7. Pascal

    Pascal Senior Member

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    If you have a connection between your fresh water system and the chilled water loop, common on cruisair, there should be a valve that will only be opened to top off the loop. I rarely have to do it, maybe twice a year. I was told 15 PSI is ideal. No more

    I was also told that in locations where freeze isn’t a concern, pure water is fine. No need for glycol but I am sure others may feel differently

    On my Hatteras the Flagship system uses water only. Pressure and level is maintained with a small 5 gallon tank located at the highest point in the system. Simple. It works
  8. captholli

    captholli Senior Member

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    The Glycol in your chiller loop doesn't care about the geographical location of the vessel but rather helps lower the freeze point of the loop from your chiller plates or if your freeze up controls go south on you. Glycol also helps thermal transfer or conductance of the loop from the chiller plates.
  9. Capt J

    Capt J Senior Member

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    This, and I haven't been on a yacht with chillers that didn't slowly lose water somewhere in the chiller loop and make up water needed to be added every 1-3 months. With so many hose connections and hoses routed throughout the entire boat, they tend to leak a little at a connection somewhere and considering most connections are hidden inside insulation, it's hard to find. IF you have a leak so large that you're constantly adding make up water, then you have a problem and need to find the leak.
  10. Seasmaster

    Seasmaster Senior Member

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    Update on the project: According to manufacturer, the original installation was done at factory, with the original purchaser of the vessel specifying Dometic. However, as Cap'n J opined, LEAKS, LEAKS, LEAKS!!! Leaks at the 6 air handlers where the hose is clamped to the supply & return nipples. Leaks at T-connections in the flexible HEP2O chiller lines. Leaks on the chill-water pump connection to the potable make-up water.

    Apparently the original raw-water pump was replaced with a over-capacity SW pump. Current pump is 20gph, but according to Dometic the system requires only 12-16gph. Dometic says the over-capacity is causing premature wear on the chiller units (2ea TWC24).

    Additionally, according to Dometic the system should be running 1" trunk lines, with 3/4" going to the AH's. What I have is 22mm and 15mm HEP2O. So as I learn that Dometic is using inside diameter, and HEP2O is outside diameter, it becomes pretty obvious that the lines are too narrow. 22mm OD is 18.8mm ID, or .7401575 (using my conversion app on phone - doesn't everyone want 7 significant digits in the solution??LOL); so I'm at least 25% undersized on the trunk lines!!

    This is getting ugly - - FAST!!! As the third owner, I'm dubious of any warranty/legal claims against the manufacturer for reimbursement for replacing components and water lines.
  11. Hello Im new here not sure how to start a new thread, anyhow I have been installing a cruisair self contained unit on my chris that was gave to me, basically with missing parts. I have everything installed with a new 3 Knob switch panel, My question is what on the 3 knob panel turns on the reversing valve? I may have it wired incorrectly cant find wiring diagram for older 1980s stuff. As of right now when I go from FAN to RUN the reversing valve comes on right away, I thought the WARM/COOL thermostat knob should do that, so what happens is it will heat fine then compresser cuts off for maybe 5 seconds tries to restart and trips breaker, so Im thinking its wired wrong, again this project I had to piece togather and Ive done well so far but having this issue with wiring. I haven't ruled out low Freon either. Also unit will not cool unless I unhook wire to Reversing valve, as I said I thought the control of reversing valve should be done in thermostat, Please correct me if Im wrong and Thanks for any help.
    Jamey
  12. Seasmaster

    Seasmaster Senior Member

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    Jamey, call Dometic technical support line. Google search "dometic fort lauderdale" and you'll see it. Good luck, dude!
  13. Thanks!
  14. Pascal

    Pascal Senior Member

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    Definitely a crappy instal. Rule nr 1 follow the manufacturer recomendation for pumps and hose size. That s what I did when i self installed the Flagship chiller system on my 53. I had a couple of slow leaks at manifolds in the ER, quickly resolved, but never at the air handlers. If an installer can’t use the right barb and hoses on the chiller water loop hopefully they didn’t screw up the sea water side as it will sink the boat
  15. Seasmaster

    Seasmaster Senior Member

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    The DOMETICMEISTERS have set me up with the proper schematic. 1.25" Chiller supply & return lines to first split. Thence 1 inch supply & return lines, with .75 inch running to the AHU's. I'll be replacing the two 24K BTU's with a single 12-48K variable unit, and new AHU's all around. The ball valves in the system will be 316 stainless, not the crappy one's with ferrous metal fasteners on the handles. And I'm not going to have 1" chiller outlet water reduced to 3/4" and then enlarged to a 1" manifold, before being reduced again to 3/4" as it is now!!! Worst piping I've ever seen-and I'm not an engineer!!

    IMG_0448.jpeg
  16. Capt J

    Capt J Senior Member

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    All sounds good but I certainly wouldn't go to a single chiller. If you lose that you have no air conditioning through the entire boat and possibly for 2 weeks if you need to order a new chiller.
  17. Seasmaster

    Seasmaster Senior Member

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    Skippy J - Yeah, I've pondered that possibility, and came down on the side of a single. Given the system will be all new, and that by going to 1 unit, I will have "maintenance" space & less weight. I've concluded that the probability of loosing a unit is minimal. I mean, heck, in the almost three years I've had the boat, I never had a chiller fail - - - Instead, I had a whole system "fail". LOL And should I have a fail, most likely I'll be in CONUS and get a replacement relatively quickly.

    On the serious side, I really do appreciate your suggestion.
  18. Pascal

    Pascal Senior Member

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    I would never do a single chiller system. Never. I would never buy or recommend to an owner a single chiller boat. Never. Ever. :)
  19. Capt J

    Capt J Senior Member

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    +2000000
  20. wdrzal

    wdrzal Senior Member

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    An A/C compressor needs 2 to 5 minutes so the high side and low side pressures can equalize or the internal self resetting overload protection device will open, you'll hear a click. After about 5 minutes of cooling off you'll hear it click closed . Depending on how close the breaker is sized to the LRA (locked rotor amps) the breaker may also kick . This is called short cycling, all modern cooling and heat/cool thermostats have a delay built into them. If your thermostat or control device does not have this built in you must wire a delay device in the circuit ,I prefer adjustable ones, say 1 to 5 minutes. One more thing, the delay device can be on the primary power supply 240 volt but the low voltage delays are much cheaper and smaller in size and go into the control circuit which I prefer
    Last edited: Mar 19, 2019

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