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Thread: Dragon Pump Testing Results

  1. #1
    Honmei
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    Dragon Pump Testing Results

    I have completed the testing of SCV's Dragon pump over the weekend. I am waiting to share the results with SCV (I've left a phone message for him) before making those results public.

    Steve

  2. #2
    Honmei KoiCop's Avatar
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    bump . . .

    (nfm) Don

  3. #3
    Honmei
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    Still no reply so posting results

    After 2 days without a return call and no response on the board to this thread and even though I told SCV that I would let him know the results before posting, I will do so anyway since I do not see any board activity on his profile since 10/1.

    Here are my results, called as I saw them. I'll be happy to answer any questions that anyone may have.

    Dragon Pump test results



    An issue with a Dragon pump arose on Koi Bito not to long ago. A Mpeg video was linked to the post showing a leakage between the leaf trap lid and housing. After repeated discussions between the pump owner and the manufacturer they had reach an impasse on a course of action. I suggested to William Lim, the pump manufacturer that perhaps an independent test on the pump be performed in an attempt to find a solution. I also expressed my interest and wished that I was closer to the owner so that I could see the exact application that the pump was installed on. After numerous discussions with William concerning this situation he asked me if I would be interested in performing the independent testing. With the stipulation that I call’em as I see’em and that the original pump be replaced, William gladly agreed to the conditions.



    It is important to note some of the background information, business concerns, and previous testing protocols. First and foremost, pumps are designed to “push” water and have a limited capacity to “pull” water. The Dragon series of pumps have a larger capacity to “pull” water (suction pressure) and thus are typically used in self priming situations where the pump is positioned close to, but above water level. Even in these applications, a check valve should be place on the suction side below water level so that the priming process can be improved.



    Pumps are designed for installations within certain design criteria. Typically pumps are tested using what is commonly referred to as a “bench test”. In the fire pump industry as an example a pump will be tested at different points along its pump performance curve. These points are “simulated” using control valves to restrict flow through increased head pressures along with measuring supply suction pressures. These methodologies are critical when dealing with life saving equipment such as fire pumps. In the pool and pond pump industry, these same methodologies are not as common and testing typically only is done on the flow rate under a single set of conditions, typically a fully flooded suction side.



    Since the overwhelming “issue” with pumps is the flow rate, this is what is typically tested, with a “perfect” supply. If the flow rate is maximized under these conditions, problems then typically are from the discharge piping design/restriction, or a supply side design/restriction and the pump is said to be functioning properly.



    The pump in question was brought in and tested under these conditions and performed to its designed specifications. I do get the feeling that a communication issue existed between the parties on the exact installation configuration though. In talking with William, he expressed that the configuration explained to him and much later explained to me were different and at the time was concerned with a restriction on the suction side of the system, before the pump. When evaluating or tracking down problems, it is imperative that the configuration is known and totally understood. Unfortunately, in our hobby many installers, whether professional or do it yourselfers, do not fully understand the dynamics with which they are actually working. This ultimately leads to confusion and misunderstandings between all parties when problems arise. Even in my case, something as simple as the type of pump in question was not clearly identified. It was said to be a Dragon 1/3 hp pump and upon arrival to me, the pump was actually a ¼ hp Dragon. This could have totally thrown off my testing process since the 2 pumps create differing design suction head pressures.



    In short, for a manufacturer or even dealer to totally evaluate an issue, they not only have to have the knowledge (which William Lim does have), but also accurate data in an attempt to evaluate the issue completely. As I alluded to earlier, unfortunately, in our hobby, too few people on the installation side have this expertise and although William has done some site visits (not in this case), its not reasonable for a manufacturer to travel to each site to evaluate a “possible” problem, especially if on a nation wide basis.



    Now, all of that being said, let’s talk about the pump itself, a ¼ hp Dragon (not 1/3 hp). I waited to unpack the pump until I arrived at Tim Cash’s this last Sunday. The pump came packed perfectly using the new pumps’ packing material and box. I did a careful visual inspection while pointing out some specific concerns to Tim so we could document our findings. The pump was in excellent shape with not much (if any) signs of wear and tear or transport damage. I carefully examined the wet end housing ensuring that the seals appeared to be in place. I took the lid off of the leaf trap and visually inspected the lid, the “O” ring and the housing flange. I replaced the lid and took another look at its seal. Upon very close inspection (I missed it the first time before removing the lid) I noticed what appeared to be an area where the “O” ring was not compressed between the lid and housing flange. If looking straight down at the trap area and where the discharge port is being at 12 O’clock, the uncompressed area was from approximately the 10 O’clock position to about the 1 O’clock position.



    I removed the lid once again and inspected the “O” Ring and lid and all appeared in order. I then, very carefully examined the housing flange and there was a barely visible “dip” in the area previously described. In addition, when closing the lid on the flange by twisting, the lid slid all the way to the end “stops” fairly easily instead of the typical increase in pressure needed to cause the clamping and thus the seal.



    Tim and I then removed his existing 1/3 HP Dragon that is approximately 5 years old (Was my own previously). The system that we used for the functional test was about a 1’ vertical elevation from water level with about a 30’ horizontal draw distance. The pump in question was fitted in place and started. It would not self prime. Since this was not the same as the 1/3 hp that it was originally thought to have been and thus an equal “test”. We primed the pump and restarted it. As the pump built up suction and began to draw water, a rather loud thumb and rush of air entered the trap area from the 10-1 O’clock position area mentioned earlier. This was evident as we saw the lid give slightly in this area.



    After the visual inspection and this functional test, it was evident that there was in fact a problem with the pump. A problem that would not have been evident when using the typical bench testing method. It is important to note that the symptoms describe could have been due to a number of possibilities, not all of which would have involved the pump.



    After witnessing the actual results of the inspection and initial testing, I cancelled the vacuum testing since it was obvious that the pump would not hold a vacuum. I am recommending to William Lim to have available a vacuum test when similar issues, should they arise in the future, occur. I purchased a $30 automobile vacuum testing kit from the local auto parts store for this purpose. Having unions within short piping and capped ends along with a suction point hook up for the hand vacuum pump makes for a decent tool in evaluating these types of issues.



    I notified William of my findings today. He has been in direct contact with Waterway, the wet end housing manufacturer. According to William (I am certainly “dumb” when it comes to plastics molding), problems like those described are typically caused during the removal process of the wet end from the mold when the cooling processes is not correct. He speculates that there is a possibility that there may be other housings that could have the same depression I noted. Some may effect the actual workings of the pump (depending on the system configuration and the suction pressure verses supply ability). He suggested that if anyone else has a similar issue that they contact him directly with the specifics of their application.



    Although SCV had some frustrations attempting to get his circumstances addressed, he reports that his new (bigger 1/3 hp Dragon) is running fine on his system and I sincerely hope that all parties involved learned some valuable facts as a result. I left the pump with Tim Cash. Although I see no point in further testing (as evident through the cancellation of the vacuum pump test), William may also want Roark to review/test the pump. This is up to William to decide.



    Keep this in mind, I did this just to do some “tinkering” and “halp out”. I received no compensation. I am also not in a position to intervene in any/all future issues between parties either. I do hope however that both parties received benefit from my involvement. After all, its all about the hobby!



    Steve Childers

  4. #4
    Daihonmei aquitori's Avatar
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    Steve has there been a head to head pump test with Artisan pumps? Also in what scale appilcation does the Lim pump do well in? Meaning on a 1 pump setup or more than one pump setup?

  5. #5
    Administrator Brian's Avatar
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    Thanks for your work and effort on this Steve. I think that it's invaluable information to all parties concerned. Good show!
    Brian Sousa
    Koi-Bito Forum

  6. #6
    Sansai
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    Thanks for the update steve - it's good to know some methods to use when troubleshooting these sorts of problems.

  7. #7
    Honmei
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    Aquitori

    The purpose of my testing was to see if their was a problem with the pump or not. There was and the issue addressed with the owner and William addressing the defect with Waterway. It was not set up to be a comparitive test amongst pumps. I've never tested an Artesian pump before. I have tested Wave 1, 1/4 hp pumps and Dragon 1/3 hp pumps and those results were actually better than the performance curve that are published for these pumps. I've tested another brand and the pump did not meet their published performance curve in my testing.

    As for the second question you asked, I am not clear as to what you mean?

    Also in what scale appilcation does the Lim pump do well in? Meaning on a 1 pump setup or more than one pump setup?
    A pump should be "sized" (regardless of brand) to meet the system that it is being installed on and every system is different since supply piping, dicscharge piping all creates differing friction losses.

    As a general rule of thumb, I typically recommend Lim pumps based on their performance curves and pumping capacity per watt used (differing pumps for differing applicationsbut this is not to say that other brands may not work as well also since the system design criteria creates differring needs for each system.

    As an example, for a gravity supply system wanting approximately 3000 gph true flow, I would spec out anywhere from a 1/5 Wave 1 to a 1/4 hp wave 1 for a fully flooded supply. The actual pump size would then be determined by the plumbing hydrolics. Pump/filter location near the pond with minimal head loss would be the 1/15 hp. A system with a bead filter after the gravity chambers and pump would be the 1/4hp due to the increase in head loss. These are just examples.

    If the pump were to be above waterline, I'd look at the Dragon series due to its higher operating suction pressures. This still does not eliminate the need for a check valve on the supply side below water level.

    Likewise, I typically opt for the dragon series (1/3 hp) for skimmer systems or systems with bead filters that create more head loss. Actual pump size varies based on the specifics of the actual system.

    Keep in mind, I work an a system concept of one drain, one filter/pump system for each 5-6000 US gallons (depending on geographic climate for the pond). A 12' diamter, 6' deep area is roughly 6000 US gallons (depending on bowling of floor). For larger ponds, this same "system design" is then replicated. Skimmer systems and midlevels along with TPR placement also become factors based on individual design criteria.

    Of course, I am just a simple hobbyist

    Hope this helps

    Steve

  8. #8
    Daihonmei aquitori's Avatar
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    Thanks, Steve....

  9. #9
    Honmei
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    Some additional thoughts

    Tom C had asked in the other thread what I would have done. Hindsight is always 20/20 and I didn't answer the question then and held off to after I had had a chance to see and really evaluate the issue(s). In all honesty, placed under similar circumstances, I am not sure that if I was William I would have done anything different. Likewise, if I were the consumer, SCV, I am not sure I would have done anything different either!

    From a maqnufacturers standpoint, the pump was tested and did not leak or perform outside of its design parameters. From the consumer standpoint, the pump leaked in its application! Heck of a quandry! As a pump manufacturer, it is "common" for there to be suction leaks in the piping to a pump that causes loss of prime. As a consumer, I can't find a suction side leak in my piping!

    As a manufacturer, I tested the pump in a normal manner not knowing the installation was different. As a consumer I didn't know the installation mattered!

    I could go on and on. As knowledgeable as William is, I even had to remind him that a fully flooded suction side (installation below waterlevel), like is his bench test, provides supply to meet the demand and the suction pressure did not have to build up to prime the pump and as such no leak was found. In the above waterlevel application, suction pressure built and the vacuum leak occurred. William now has a method to test for this as well by vacuum testing the pump. If the testing system holds the vacuum to the suction pressure design of the pump and there is still air/lack of prime, then it has to be on the piping system to the pump. One thing that I believe was the biggest contributor to the long "timeline" was the lack of understanding by all parties of the conditions/system.

    Steve

  10. #10
    Tategoi
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    Excellent report and I love the part about how to test for this in the future ($30 vacuum device).

    One more step to the qualification process for pumps but cheaper to find the problem there than in the field.

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