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  1. #1
    Join Date
    Dec 2010
    Posts
    26

    chiller btu testing

    just wanted to know if this was a proper way to do a basic btu test? thanks
    Wes,

    I have attached the BTU test sheet for a 1-ton chiller. Please note the bottom right corner for a place to keep the temperature for each minute. The instructions for the test are as follows:

    1) You must have the exact volume of water contained within the chiller and system. It would be easiest to calculate this volume if you can tie the input and output lines together that run to the air handler. Or, you must empty the system and measure the amount of water exactly to the gallon that you add to fill the system completely.
    2) Allow the water to heat up and stabilize to around 90-95 degrees F either by allowing the pump to run without the compressor kicking on or cut the thermostat of the chiller up to 90-95 degrees to allow the water to get that hot and once it reaches 90-95 then set the chiller thermostat down to 45 degrees and when the compressor kicks on allow a few moments for the refrigerant to flow and the unit to begin working. When the temperature begins to drop start timing and start recording the temperature.
    3) Measure and record the temperature of the water each minute for 10-15 minutes. After the 10 or 15 minutes stop the refrigerated part of the chiller but leave the pump on and write the temperature down. Monitor the temperature and if it drops any further then use this as a final temperature.
    4) Take the total volume of water(in gallons) and multiply it by 8.34 to give you the total weight of water in lbs.
    5) Take the total weight of water in lbs. and multiply it by the total difference(starting temp vs final temp) in temperature measured on the water from step #3.
    6) Take the number you get from the calculation in step #5 and multiply it by 6(if you measured water temp for 10 mins) or by 4(if you measured the water temp for 15 mins) to give you the total BTUs.

  2. #2
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,609
    GPM times delta T divided by 24 = evaporator tons

    You're goin' around the world to get next door with that nutroll of calculations you're talkin' about........

  3. #3
    Join Date
    Dec 2010
    Posts
    26
    so basically the formula i have is in-correct? what is delta T?

  4. #4
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,609
    1 ton or 1000 tons, if you're working with a chiller and you don't know what delta T means, you're way behind the power curve. It's temperature differential between inlet and outlet water. For any more info than that, you'll have to put some history in your profile so we'll know who we're speaking with and what your level of experience is.

  5. #5
    Join Date
    Dec 2010
    Posts
    26
    i bought a 10 ton chiller and installed it myself. It doesnt seem to be working at any were near 10 tons using two separate williams air handlers for cooling. I have a hvac contractor servicing the unit, and i want him, or me, to do a btu test after i spent alot of $$. I'm mechanically inclined, but i only have general ac knowledge. The manufacturer is the one who gave me the btu test which i posted on this link. temperature differential can easily be done, sounds like the gpm flow will be the harder measurement.

  6. #6
    Join Date
    Dec 2008
    Location
    Dixiana, AL
    Posts
    2,609
    "Chillers Use this forum to discuss all about chillers. Remember, no DIY."


    This is the heading at the top of the thread listing. Pay special attention to the last sentence. It's time to let your contractor do his job, or find someone that is familiar with what you need and get them to do it.

  7. #7
    Join Date
    Nov 2006
    Location
    US
    Posts
    112
    What is the Brand and Model # of your chiller

  8. #8
    Join Date
    Dec 2010
    Posts
    26
    it is a 10 chill king chiller. They are a mom and pop shop. I always try to let contractors do there jobs, and chill king gave me the formula to test the unit. The contractor said he had never heard of this method, but it was a simple test without a precise flow meter to test gpm so we did it. The unit only tested at 83,591 btu. I honestly think that is correct. The reason for the test and calling the private contractor, was because the unit wasn't keeping up with the demand of any were near what a 10 ton should perform. I am extremely disappointed in the unit, and the customer service from chill king in Texas.

  9. #9
    Join Date
    Dec 2010
    Posts
    26
    I appreciate any help.

  10. #10
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,623
    have you checked evap flow to chart, to make sure your not moving water to fast?

  11. #11
    Join Date
    Dec 2010
    Posts
    26
    No i have not checked that, it uses a 1.5 hp flotec jet pump. I will look into that.

  12. #12
    Join Date
    Dec 2010
    Location
    Down by the river
    Posts
    1,623
    what a 1.5 hp jet pump, thats what I use on my irrigation system. holly cow.


  13. #13
    Join Date
    Dec 2010
    Posts
    26
    I brought this to chill kings attention, and they said that typically they use a 1 hp, and did not think that it was a issue. The contractor believes the problem could be the homemade coil in tank they installed on the chiller, for a heat exchanger. He is recommending a plate heat exchanger. I'm just not sure if i want to spend a few thousand more into the unit for parts and labor, without a guarantee it will perform at the 120,000 btu of cooling or close too.

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