Click for Westport Click for Abeking Click for ZF Click for Lurssen Click for JetForums

Chiller help

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

You need to be registered and signed in to view this content.
  1. bayoubud

    bayoubud Senior Member

    Joined:
    Feb 19, 2017
    Messages:
    482
    Location:
    Florida
    After checking Scot pump specs, our 1/2 hp pump specs require a 3" or 31/2" impeller. Ours has a 4" impeller which is Scot spec for the 3/4 hp motor. I doubt our pump came from Scot, it was put together by a tech or rebuilt with the wrong impeller in the last few years. Any way, decided to go with whatever the mfg specs and not question their recommendations. The new pump will be a CD100 1/2 hp by Aqua Air and should solve any low flow problems caused by the wrong pump setup. Cleaned and descaled the copper manifolds for the chiller input/output yesterday and was surprised at the scale buildup inside the piping. Apparently the system had been using dock water with low glycol mix for a long time. Like most with the makeup water being plumbed to the water tank this situation would be hard to avoid with low glycol or any leaks in the system. Something to consider when purchasing an older boat with a chiller system, would require extensive invasive work by a knowledgeable tech during surveys. We will have replaced every component of the system except the loop piping when finished. Not trying to to highjack this thread but thought this could be useful as to what can go awry over time without proper maintenance.
  2. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    11,330
    Location:
    Fort Lauderdale
    I have seen all sorts of weird iterartions of Scot pumps. So that's nothing unusual.
  3. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA

    Is there a better way for the "makeup" water system? If one has a small leak that remains undetected, one could have zero glycol and 100% water [my situation].

    After doing a little exploration for the salt water pump, instead of using a 3400 RPM pump with a 2.5" impeller in a 3.5" housing [which just doesn't sound efficient] I went with a 1800 RPM pump with a 5" impeller. It was a little more $$, but should run much quieter [it's under the deck of the main salon], and last longer. The discharge volume is the same. The AC guys seem to have a problem supplying the chill water pump, so I'm exploring using the same manufacturer of the SW pump for the CW pump, with the proper flow, of course! IMG_0678.jpeg
  4. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA
    Here's the comparison between the proper sized trunk line for my boat [using 1" copper, not the plastic garbage], and what boat builder used, 22mm. And one must remember, when the trunk line was "T connected", as well as unions, they had to put inserts, which further restricted the flow, to make the connection. Beyond comprehension!!!!:mad::mad:

    Attached Files:

  5. bayoubud

    bayoubud Senior Member

    Joined:
    Feb 19, 2017
    Messages:
    482
    Location:
    Florida
    Huge difference in ID. Did you know they were installing a complete new chiller system without a pump?
  6. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA
    I'm doing a whole system change-out. AHU's, CW pump, Chiller, Trunk lines, valves & T's. They said the SW pump was fine with a 2.5" impeller instead of the 3" that was in it. However, it was discovered that the pump was leaking, so I was faced with a re-build or replace. I chose replace. The "dead" one was a 2 year old [Sept 2016] Scot, so I was looking for a longer lasting pump.
  7. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    11,330
    Location:
    Fort Lauderdale
    Make sure whatever glycol you're using doesn't eat copper as well as whatever fittings you're using to tie it all together. They use rubber hose for a few reasons, like bends and stuff like that and it can be quieter if you have any air in the system.

    You can't NOT know you're using make up water as you should have a gauge and only add water to the system manually with a valve.

    I really don't understand how you're over engineering the one end of the system, but then only putting one chiller, which is going to be your biggest mistake in the world. Just wait till it breaks with guests on board and you need to wait 3-4 weeks for the part to fix it. Loose the 1 chiller and the entire boat has no a/c. Meanwhile with a second chiller, you can just motor on while the part arrives. A/C's always break when you're on a trip and in the middle of nowhere, never at your home dock.
  8. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA
    The answer is: I've assessed my usage of the vessel in the last 3 years. Number of guests aboard at any one time was 3, for a day cruise around Central FL. Intended usage is to loop with current girl friend. Space available for the chillers is small, very-very-very small [look at post #35], and trying to work on one would require many labour hours to remove access ports on mid-ship berth, and possibly remove one of the two units to work on the other. Having had one repair job for a sensor was sufficient to convince me.
    If the AC fails, I'll moor the boat, fly home until it's fixed. It's not a charter vessel, it's a floating RV!! And in an RV, if the AC stops working, use the "Two-Sixty" model - Roll down two windows and go 60 mph!! LOL I've lived on ships for half my life - and sometimes the AC went kaput. So long as I have beer in the fridge, and the ice maker is producing, I'm good. Captain Bligh said it best: A true sailor can sleep in an oven, or on a cake of ice!! LOL
  9. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA

    As I learn about the system, I also have learned about the maintenance habits of the vessel's two prior owners [most likely their captains, though]. I'll admit to being ignorant of some system maintenance - education does come at some cost - and as a deck officer, I didn't get play with the engineering systems on the ships. But, one of the owners [captain's] opened up the make-up water supply valve on the AC system before I bought the boat. . . sigh. Doom on me!

    Another example of the prior owners' [or captain] maintenance. When I purchased the boat in 2016, the water maker had 3 hours on it [Date of installation is unknown]. In 2018, when I was transiting in the LANT, I started it up. Of course it wasn't working properly. But when the tech came out to trouble shoot, and "educate" me, we discovered that the three pre-filters had no filter element in the containers!!! Now what idiot would take filter elements out, and not replace them??? Sigh!!

    At the end of the day, some stuff just isn't "surveyed" at the buyers survey. But if there IS a next time, I know what & where to look!! Yachting is so much fun, and educational too. But I did pick a bad year to stop drinking!! LOL
  10. bayoubud

    bayoubud Senior Member

    Joined:
    Feb 19, 2017
    Messages:
    482
    Location:
    Florida
    I don't leave the make up valve on, just keep watch on the pressure, add as needed. Test the glycol mix if adding much water. Finally fixed my leaks so may not need to add much water. Ampco pump looks heavy built and like the lower rpm, good choice.
  11. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA
    Christmas in April. . . New Chiller has arrived - 48K BTU variable with titanium coils!! And 6 new air handlers.

    Now the real work begins. A real-life lego set for sure!! Lot's of tight little spaces in the boat to work with. IMG_0818.jpeg IMG_0703.jpeg
  12. chesapeake46

    chesapeake46 Senior Member

    Joined:
    Jul 26, 2009
    Messages:
    1,264
    Location:
    Chesapeake Bay, Delaware Bay & S.Jersey
    Good luck and keep the pictures coming !
  13. JWY

    JWY Senior Member

    Joined:
    Feb 22, 2004
    Messages:
    1,146
    Location:
    Ft. Lauderdale
    Holy moly! Are you Elling or Yelling?
  14. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA
    at needs a little jewelry. You know: BLING IMG_0720.jpeg

    Groco valves & unions with some hex nipples for good measure. . . Just mapping out the "how" and "where".

    Now "they" did get one hose "right" on the original installation from the manufacturer; a 25mm lead. The requirement is for 1", so I'd accept the mm equivalent of .984252 as "close enough".


    IMG_0832.jpeg

    But whatever "good" was done with the 25mm, it was "undone" by stepping down to 5/8" through the reducing ball valve.

    IMG_0831.jpeg

    that had some ferrous metal in it, and hose barb connection that further reduced the flow!! Dometic wants to see 3/4" FULL FLOW to the AHU's in the new application.

    And remember, this installation is not increasing the factory original 48K BTU AC unit, nor are the AHU's being increased.

    IMG_0833.jpeg
  15. bayoubud

    bayoubud Senior Member

    Joined:
    Feb 19, 2017
    Messages:
    482
    Location:
    Florida
    That is a lot of bling! What size copper tubing on the A/h's?
  16. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA
    The chill-water pipes on the AHU's are 1/2". Dometic want's to see 3/4" supply going as close to the AHU as possible before reduction. . . Yeah, 5/8" is close. I get it. But it is still "under-spec". And the whole system was configured with "under sized" piping.
  17. Seasmaster

    Seasmaster Senior Member

    Joined:
    May 25, 2016
    Messages:
    159
    Location:
    USA
    Salt water pump set up, with the 12" rise as required by Dometic. The original installation had the discharge coming out horizontally right into the SW supply line.
    IMG_0985.jpeg

    Same thing on the chill water pump package; 12" vertical rise. The original installation had the discharge coming out at the top, but no rise; just a 90 degree elbow.

    IMG_1006.jpeg

    The installer is now setting up the copper lines and making connections. I just might have AC running by 04 June. It's been an arduous process.
  18. bayoubud

    bayoubud Senior Member

    Joined:
    Feb 19, 2017
    Messages:
    482
    Location:
    Florida
    I hear ya... equipment and plumbing connections look good. Been months on ours and now on third tech if that makes you feel better...we are getting close...maybe by end of week.
  19. Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    7,370
    Location:
    Satsuma, FL
    You would be amazed how many installs we had worked on with-out the quick connect couplings.
    We always installed them during our work.
  20. Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    7,370
    Location:
    Satsuma, FL
    Third tech???? Whisky Tango Foxtrot????

Share This Page