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  • Custom Chiller - What Would You Pro's Do?

    I have an aquarium chiller that has a custom made heat exchanger. The company that made the unit has gone out of business. There is no documentation. The main chassis and compressor are still made. See the specs below:
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Copeland M2FH-0026-IAA-102

    Compressor: AR27CIE-IAA-100

    DT Code 19A00

    Max Evap Temp = 45 degrees F

    It's single capillary tube metering.
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    The model number translates to: M series, R-134a, Air-Cooled, High Temp, Revision 0, 1/4 HP, 115 volt, 1 phase, 60 Hz, no valves

    The compressor model number has changed, the specs haven't. I have a new compressor in the box.

    The problem is that this unit was designed to be an air to air unit versus and air to water unit. The custom exchanger is an 8" long, 3" PVC pipe shell with a 3/8" diameter titanium coil of some sort inside. Length and configuration are not known. 575 gallons per hour of 1.027 salinity sea water flows though 1" connections. In the past, there was a 1 degree F drop across the exchanger (at 575 gph).

    The Copeland spec sheets have no information regarding minimum system charge to keep the compressor cooled. Any kind of exchanger should be "add X amount of charge per foot of tubing". I have spec sheets for both the air M2FH and water M2WH systems. Both say:

    BTU Capacity at 60 Hz with 5 degree F subcooling.
    HT Models are rated at 65 degree F return gas temperature.

    The system was working fine per the customer with the exception of the compressor making a huge rattly noise on shut down. It was very wobbly like a spring support broke. I weighed the recovery cylinder before and after the evac process and found only 5.8 oz of refrigerant had been removed. It doesn't sound like enough but I have no frame of reference.

    Should I ignore any presuppositions I have and charge based upon the spec sheets even though there is a non-standard heat exchanger installed? My concern is that there may not be enough charge to properly carry oil through the system. Temperature shouldn't be any problem. Then whatever comes out the chilled side "is what it is" right?

    I will be adding service valves to the system. Would it be OK to add a small filter drier on the compressor outlet?
    Last edited by Plumber Punky; 03-23-2013, 09:53 AM. Reason: clarity
    ~~

    ... it was plumbed by Ray Charles and his helper Stevie Wonder

  • #2
    Re: Custom Chiller - What Would You Pro's Do?

    If your instalilng service valves you should be able to put some gages on it and see if the charge is suficant, in my thinking, but my experence is not that great in cap tube systems, adding a dryer filter I would think would be good, (it would add the needed charge amount),
    Push sticks/blocks Save Fingers
    ~~~~~~~~~~~~~~~~~~~
    "The true measure of a man is how he treats someone who can do him absolutely no good."
    attributed to Samuel Johnson
    ~~~~~~~~~~~~~~~~~~~
    PUBLIC NOTICE: Due to recent budget cuts, the rising cost of electricity, gas, and oil...plus the current state of the economy............the light at the end of the tunnel, has been turned off.

    Comment


    • #3
      Re: Custom Chiller - What Would You Pro's Do?

      fliter dryer goes in the liquid line not compressor discharge line. if there gage ports i would charge it using superheat not subcooling. so you don't slug the compressor.

      Comment


      • #4
        Re: Custom Chiller - What Would You Pro's Do?

        Originally posted by jeff View Post
        fliter dryer goes in the liquid line not compressor discharge line.
        Yes, after the coil but before the metering. Poor terminology on my part.

        if there gage ports i would charge it using superheat not subcooling. so you don't slug the compressor.
        some other people also suggested a sight glass. I can see where this would be helpful.

        The filter drier has a convenient chart noting additional charge needed after install.

        Click image for larger version

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        ~~

        ... it was plumbed by Ray Charles and his helper Stevie Wonder

        Comment


        • #5
          Re: Custom Chiller - What Would You Pro's Do?

          Originally posted by plumber punky View Post
          i have an aquarium chiller that has a custom made heat exchanger. The company that made the unit has gone out of business. There is no documentation. The main chassis and compressor are still made. See the specs below:
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          copeland m2fh-0026-iaa-102

          compressor: Ar27cie-iaa-100

          dt code 19a00

          max evap temp = 45 degrees f

          it's single capillary tube metering.
          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

          the model number translates to: M series, r-134a, air-cooled, high temp, revision 0, 1/4 hp, 115 volt, 1 phase, 60 hz, no valves

          the compressor model number has changed, the specs haven't. I have a new compressor in the box.

          The problem is that this unit was designed to be an air to air unit versus and air to water unit. The custom exchanger is an 8" long, 3" pvc pipe shell with a 3/8" diameter titanium coil of some sort inside. Length and configuration are not known. 575 gallons per hour of 1.027 salinity sea water flows though 1" connections. In the past, there was a 1 degree f drop across the exchanger (at 575 gph).

          The copeland spec sheets have no information regarding minimum system charge to keep the compressor cooled. Any kind of exchanger should be "add x amount of charge per foot of tubing". I have spec sheets for both the air m2fh and water m2wh systems. Both say:

          Btu capacity at 60 hz with 5 degree f subcooling.
          Ht models are rated at 65 degree f return gas temperature.

          The system was working fine per the customer with the exception of the compressor making a huge rattly noise on shut down. It was very wobbly like a spring support broke. I weighed the recovery cylinder before and after the evac process and found only 5.8 oz of refrigerant had been removed. It doesn't sound like enough but i have no frame of reference.

          Should i ignore any presuppositions i have and charge based upon the spec sheets even though there is a non-standard heat exchanger installed? My concern is that there may not be enough charge to properly carry oil through the system. Temperature shouldn't be any problem. Then whatever comes out the chilled side "is what it is" right?

          I will be adding service valves to the system. Would it be ok to add a small filter drier on the compressor outlet?
          fish fry
          I can build anything You want , if you draw a picture of it , on the back of a big enough check .

          Comment


          • #6
            Re: Custom Chiller - What Would You Pro's Do?

            There's more corals than fish really. I'll have to look around to see if i have a picture of it someplace. It's a 125 gallon setup with a small reef arch and column structure.
            ~~

            ... it was plumbed by Ray Charles and his helper Stevie Wonder

            Comment


            • #7
              Re: Custom Chiller - What Would You Pro's Do?

              I will start by disclaiming that my knowledge is based on servicing car a/c systems so I'm not sure how that translates to your system.

              That said - generally most of the compressor's lubricating oil resides in the compressor. Some oil does move around with the refrigerant but that's not much. When servicing automotive compressors there is an oil fill port on the compressor. In a well designed system there should be a low pressure cut-off switch which should turn off the system if the refrigerant pressure drops below a certain level.

              As far as charging - yes you do need to know how much to add and I generally monitor the charging process with a set of manifold gauges as well as the discharge temp and then cross check that with the charts. In the absence of charts and some understanding of how much refrigerant to add I'm not sure how you would figure it out.

              Comment


              • #8
                Re: Custom Chiller - What Would You Pro's Do?

                There's an absence of a lot of stuff with this system.

                After determining that the system holds pressure (I filled it with 125 psi, detached the gauges, waited 2 days, and reattached the gauges) the old compressor was cut out. The new one was set in place. That was easy. The old suction port exited straight, but the new port was at a 45 degree angle. I cut off the old end and hand made a loop-ty to fit to the old line. The old filter-drier was cut out and new loops were made to bring the line up and over the compressor where a new filter-drier and sight glass were installed. The end of the sight glass then dropped back down with yet more copper into a new service valve that continued to run back to the old capillary tube. It's ugly, but it all fits into a tight space. Silver 15 braze rod was used.

                I pumped it down to hard vacuum and it's not moved in pressure for over 8 hours. I plan on doing a refrigerant flush before pumping it down again and doing the final fill. Since it's a non-standard setup I plan on charging by temperature of the return gas, the Delta T of the incoming and outgoing water, and the sight glass contents. My Dad uses a 550 gph water pump but the system is rated for 220-750, so I will be using a 330 gph pump.
                ~~

                ... it was plumbed by Ray Charles and his helper Stevie Wonder

                Comment


                • #9
                  Re: Custom Chiller - What Would You Pro's Do?

                  Sounds like you are doing the right things. It is a good idea to pressure test with positive and negative pressure - you want to run the vacuum pump for at least half an hour if not more before the final fill to make sure all the residual moisture is boiled off.

                  A flush is a good idea too.

                  Comment


                  • #10
                    Re: Custom Chiller - What Would You Pro's Do?

                    HooooWeeeeeee! A few days without the chiller made the algae grow (click to enlarge)!

                    Click image for larger version

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                    I did the refrigerant flush and pumped down again for 8 hours. I refilled 10 ounces initially and started the system. The sight glass showed lots of bubbles so I then filled it until they went away. The calculated readings for subcooling didn't even come close to the spec sheets. Not a huge surprise since the exchanger isn't designed for this unit. The sheets were tossed to the side.

                    My initial setup chilled water awesomely except it acted as a soda pop cooler - it had a frozen evap coil. Sooo.... the charge was adjusted so that it wouldn't freeze again until the water being cooled fell to about 52 degrees - well below the aquarium temperature. It's probably overcharged but the vapor temp still falls below the upper end of the spec sheet.

                    The cover was reinstalled... Only to find out the new compressor is wider and longer. The side of the case hitting the copper tubing now has a *custom* flare/dent. (Read: hammered from the inside out) The power cable used to snake between the case and the bottom frame - one corner was bent up. This corner was bent back down and I drilled the case and installed a cord grommet support.

                    After installing it on the tank it took 38 minutes to drop 110 gallons of water about 3 degrees. The pump was pushing about 500 GPH. More importantly, it doesn't clank on shutdown and the old man is happy.
                    ~~

                    ... it was plumbed by Ray Charles and his helper Stevie Wonder

                    Comment


                    • #11
                      Re: Custom Chiller - What Would You Pro's Do?

                      Looks good

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