Page 2 of 2 FirstFirst 12
Results 14 to 18 of 18

Thread: Chiller GPM

  1. #14
    Join Date
    Jan 2013
    Location
    United Kingdom
    Posts
    109
    Post Likes
    If the Chiller is a York YK with Optiview , it will tell you on the Sales Order page what the design GPM should be for the evaporator and condenser, it will also tell you the design Water In/Out at full load for the correct design conditions. Delta P is not a really accurate method for measuring flow, it may be ok if you have an orifice plate , but an inline flow meter or possibly an external Ultrasonic clamp on meter will give you more accurate readings.

  2. #15
    Join Date
    Jan 2008
    Location
    Phoenix Arizona
    Posts
    1,616
    Post Likes
    I have a hard time believing you design on the primary is 70ft. Since I didn't see variable primary I assume is primary secondary. If your sized for 70 and your running at 35 I would also assume your massively overflowing the primary. Need more information at this point...

  3. #16
    Join Date
    Jul 2014
    Location
    Seattle, WA
    Posts
    259
    Post Likes
    Flow meter may be accurate, but somebody has to pay for it and make sure it's calibrated. And it's great when it's properly connected to the DDC/BAS gear and you can trend GPM (add in a amp CT on the CH and you can create a seasonal kW/Tons profile - nice to see how your CH efficiency varies per energy strategies or just for maintenance review).

    The CH evap. bundle is a 'Head-Loss' flow meter - very predictable & calibration is not required (save for the pressure sensors - that should be a one-time affair). Never use analog gauges to measure flow - use calibrated digital gauges. Using the manuf. pressure-drop curve should get you flow within ~5% (see attached). For better accuracy get the actual dP-GPM data values from the manuf. Performance Test report (eg, flow at 20%, 30%, ...100%). Not a graph but numbers.
    Someone paid big $$$ for that chiller - the manuf. should provide that data.
    Attached Files Attached Files

  4. Likes WAYNE3298 liked this post
  5. #17
    Join Date
    Feb 2016
    Location
    Louisburg Kansas
    Posts
    1,616
    Post Likes
    tridium I had a disagreement a few years ago with a control company that insisted their flow meter was correct. I knew for a fact it was wrong but when they wouldn't relent at a meeting the general called the chiller factory and told them about the disagreement between the meter and chiller pressure drop. The factory guy said as far as we are concerned flow meters have never been invented and never will be. If you have a warrantee problem the chiller pressure drop better be within design. We have tested enough chillers we know what the pressure drop should be and we did test your chiller.
    The main thing you have to be sure of is no restriction in the chiller tubes. In doing balance work I have seen more flow meters off than were accurate. I went to a demonstration of a clamp on meter and during his initial set up the guy said now I have to put in the Reynolds factor. Knowing there is no such thing I ask him what a Reynolds factor was. He never really answered and I don't think he knew there is a Reynolds number that you can calculate but no universal Reynolds factor you can use unless it is specific to their meter. My confidence in his meter went right out the window.

  6. #18
    Join Date
    May 2018
    Location
    Houston
    Posts
    43
    Post Likes
    there have been working flow meters and they were inline orifice plates where you measured the pressure drop across them and did the calculations or using pressure drop across valves using the cv factor. that is why the chiller pressure drop can be trusted its one big orifice plate creating the right flow will create the right pressure drop. What machine is this what liquid is flowing through it and what paperwork do you have on the design flow of the unit. It cant be a york because they love us and put it on their optiview and write the design feet of head inside the panel so we don't have to look for it. Is this an old machine or a new one because factory start up should clear all that up for you when the start up guy adjusts the valves to slow the flow. Also depending on how this thing is piped in his measurements dont have to be wrong they couldve put all sorts of restrictions in the piping that dropped the pressure wherever he is taking his measurements.

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.