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Chiller help

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

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  1. Pascal

    Pascal Senior Member

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    Same issue here. And my fault. I have a single drain on an inclined pan so water never stay in the paint. My mistake was a 3’ horizontal section in the ER right before the discharge. I thought 6’ head would ensure water would drain. Well slime builds up in the horizontal section and even 6’ head isn’t enough to clear it.
  2. Capt J

    Capt J Senior Member

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    T's and Y's and even unions are also great places for Algae to sit and catch on the lip of them and grow.
  3. bayoubud

    bayoubud Senior Member

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    Maybe AH was not making enough condensation to dissolve the tablets? Think I'll be adding some vinegar occasionally with the tablets. My AH's make a lot of condensation and the tablets have been dissolving, but have not had any blockage yet. The drain lines were trashy and all cleaned last spring when we replaced the AH's before using the tablets.
  4. rtrafford

    rtrafford Senior Member

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    Can you plumb in a sweep there to eliminate the 3" horizontal?
  5. rtrafford

    rtrafford Senior Member

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    YEs, my maintenance routine has been using my custom tool on one drain while restricting the second drain with a rubber cone on a wire. It's a little like surgery but has worked well. Followed that with a little vinegar. Pain in the ass, but necessary, all of it. Hopefully these tablets will simplify. Not on this boat, but once before I had opted to have a bigger pan built with a bottom-drain, with the pan pitched to the bottom. Mounts were built into this pan, and I placed the air handler into it, removing the hoses from these stock drains. Just chose to make the drain slightly larger, just one, and easier to access. To date I really haven't seen any perfect solution.
  6. rtrafford

    rtrafford Senior Member

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    Maybe we're challenged to routine vinegar-water solutions being poured into these pans routinely as a prophelactic remedy...I would have thought the tablets would perform that function.
  7. Pascal

    Pascal Senior Member

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    Yes. Easily. I haven’t had a chance to :)
  8. nguyentu

    nguyentu New Member

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    Hello guys,
    I'm a beginner. I'm planning DOMETIC's chiller system for marine.
    Diagram:
    upload_2020-3-10_14-7-35.png
    Chiller modular and 4 air handler: they are good for me
    4 x (control box Q-logic + Cruisair Q3): Is that the best choice?
    PLC controller: Does the chiller modular come with a PLC controller? or Will I have to buy an additional PLC controller? Which model do you suggest?
    All of these devices are enough for a singer Chiller system? ( not include: exp tank, pump, flow control, other accessories,..)
    Thanks!
  9. Seasmaster

    Seasmaster Senior Member

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    Can't answer the question without knowing more.
    * Are you replacing a system, or starting from scratch?
    * What/where will usage of vessel be? If you only have 1 chiller, and it dies in the Bahama summer - you will be one miserable boat owner.
    * If you haven't started discussion with an AC contractor, you are already behind the 8 ball. And the AC guy can directly answer your PLC/Q-Logic/Cruiseair Q3 questions.

    I'm not an AC guy, but the first thing I noticed is that your AHU total BTU's is higher than what the chiller will produce. Will that guarantee premature failure?? I don't know, but the AC contractor SURELY will.
  10. rtrafford

    rtrafford Senior Member

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    Here's a perspective that I've learned and am working to conquer. Many times at night or on cool days your chiller will be asked to short cycle as it is tasked solely with maintaining a temp delta on your glycol loop. That's hard on the chiller over a lifetime. I am of the opinion that a good chiller system is split into two chiller units that share the burden, with the smaller chiller unit tasked to maintain the glycol loop and nominal heat exchange. In effect, that unit is sacrificial and efficient for the short cycles as it will run perhaps a bit longer to drop the loop temperature.

    My system is 10 ton. I split it and installed two 5's with staggered temp settings for on/off. Still, some of my cycles are less than a couple of minutes in many conditions as the overall system and shell are fairly efficient (as compared to many). If I had a mulligan I would split my primary 5 ton into a 2 and a 3. The secondary 5 gets very nominal use as it is. The theoretical 3 ton would be called principally in the day time, but the 2 in this case would cycle and maintain the loop on a much more efficient basis, and it would get the brunt of the use and be the unit called for replacement ahead of the others.

    This is my theory. Take it with a grain of salt. As I am not going to replace my primary 5 any time soon, I am considering the addition of a 2 ton DC unit as a primary ahead of both 5's right now.

    Also, I used Technicold (Northern Lights). Their quality is really noticeable.
  11. rtrafford

    rtrafford Senior Member

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    I'm there as well, with my air handler tools somewhat taller than my chiller capacity. My system works fine, mostly relying on one unit running only...in other words my 12 ton of air handler is well supported by my 10 ton of chiller.
  12. rtrafford

    rtrafford Senior Member

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    I do agree that two chillers are better than one, both for efficiency as well as duplicity.
  13. rtrafford

    rtrafford Senior Member

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    ...also, CoolFit piping and valves are tremendous...
  14. Capt J

    Capt J Senior Member

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    If all you need are 30,000 BTU's of a/c and 4 units, don't even bother with the complexity and issues of a chiller system, just put 4 all in one/package a/c units and be done with it.
  15. rtrafford

    rtrafford Senior Member

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    Yeah, that, too.
  16. Pascal

    Pascal Senior Member

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    you have a point although 3+ 2 will be a lot more expensive than a single 5 and require more space. Is it worth it just to reduce the short cycling? Not sure

    one of mine was also short cycling at night, increasing the start temp helped. In winter I only run one chiller anyway
  17. rtrafford

    rtrafford Senior Member

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    I agree with the questions, worth questioning. What I'm witnessing is a short cycle that is called simply because the loop temp has climbed above 54. I dropped the shut down from 44 to 42 in hope of prolonging the shortness and slowing the restart split. Meh, ok. My real goal seems to be focused on the inclusion of a DC 2 ton, both to get off AC, make better use of battery ability given the really light LED lighting impacts, and to allow that rascal to keep the loop cold when the air handlers really aren't calling for water.
  18. rtrafford

    rtrafford Senior Member

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    ...if I can get that short cycle off my 5, can I extend that life for several years and push the burden to the smaller unit while also enjoying a DC draw for added efficiency....that's the logic behind the rabbit hunt.
  19. d_meister

    d_meister Senior Member

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    If you are planning for a complete installation in Viet Nam, Latitude 14 degrees N, you definitely should consult the manufacturers of complete systems.
    "The temperature in Vietnam typically ranges between 70°F and 95°F throughout the year. Average annual humidity is around 85%. Vietnam receives the majority of its precipitation during monsoon season, but the rest of the year also receives regular rainfall. The average annual rainfall is about 40 inches."
  20. Seasmaster

    Seasmaster Senior Member

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    I'm going to commit "sacrilege" by saying that my VAR48 chiller is AWESOME. . . It "throttles back" when the load is low. But, it certainly isn't a DC unit.:cool::D