I have a submersible pump, chinese made, no known brand that I can find. The importer has no maintenance, parts or service information on the unit. It is a vertical sewage type pump, but is intended and used for service in a pond/water fall feature.
Here’s the problem. It cycles constantly. Thermal cutout shuts the pump off, resets, cuts the pumps off, resests……about every 7-8 minutes. Obviously, this is not quite the service I expected. The pump motor has a plug in the top and it is partially filled with oil. The pump is completely submerged, water temps is about 65, and flow is/was about 200 gpm at 20 ft (runout being about 270).
Questions
1. What kind of oil goes in these thing and how full should it be? I’m thinking it would cool better if there was more oil in it. Bad idea?
2. Can the thermal cutout be replaced with one of a slightly higher temp without consequences?
Replies
"No" to both questions.
Filling motor housings with oil is rapidly running afoul of various environmental rules. Such designs are typically not intended to be serviced.
As for the thermal cut-out .... that's not a 'user serviceable part.' It often cannot be reached without rewinding the motor.
Simply put, you didn't pay much ... and that's what you got.
This thing retails for about $1250, which in the world of continous duty, 230-1-60 volt 1 hp waterpumps, IS cheap. A Goulds replacement with similar capacity is about $4000. I got the wholesaler to get me a new one at a dealer price, but still am not quite ready to trash this one. Small motor repair shop?
Wait a minute. 12,000 GPH submersible at 20' of head? You can't run that in a pond without burning it up! That's why your thermal shutoff is kicking in. Most sewage-ejector (solid) pumps are not made for continuous use. If you skip the shut-off circuit, that motor will burn up before the day is out.
To put it prices and capability in perspective, a beefy well-priced external pump driven by a Baldor motor capable of 8000GPH at 5' of head will cost (new) $800 - $1000 dollars. However, it's designed for 24/7 operation.
Submersible pumps are generally more expensive and less efficient than external pumps. PondTech makes a submersible that will deliver ~8000GPH (0 head rating) for $400 - $500. Alita makes a pump that will deliver 5000GPH at 20' of head for about the same.
There are some cheaper submersibles, but in large part, you get what you pay for. You need to look at the performance curves when you buy a pump, and try to find something that will be in the middle of its operating range under your conditions.
If you want to, let me know what your flow requirements and estimated head pressure are and I can try to give you some decent options for pumps to look for - I've been doing a lot of this lately. If you can reconfigure to go with an external pump, it drops the price and increases the efficiency considerably.
-t
I have an 18000 gallon pond and would like to have at least a 2 hour turnover (9000 gph), but now run at approximate 1.5 hr. The EasyPro pump I have is rated at 16000 gph at runout. I have about 65 ft of 3" flexible pvc and about 5 ft elevation difference between the main pond level and the outfall of the filter/waterfall. With a discharge check valve, 3-90's and the pipe (at 200 gpm) I estimate the thd to be 20 to 25 feet. Really don't have the setup to accomodate an external pump.
Hi Tim:Sorry, I'm really busy today so I'm just dashing off something quick. First off, my apologies, I didn't believe your specs, etc... you definitely have a sense of what pumps should/do cost and you DEFINITELY have a big system here. A lot of folks report decent results using the larger "Pondmaster/SurePro" submersibles. Surepro is the name that Horizon Online markets them under. I'm calculating your head as a fair bit lower?3 X 90° fittings (3" sch 40) = 3 X 8' = 24' run
65' straight PVC sch. 40 run
5' head from elev.Therefore,24' + 65' = 89'
------->
89' * 4.63(head/100'@150gpm) = 4.0 head
+ 5' elevation For 9' total dyn. head.I don't know offhand what the backflow valve adds, but it should be less than 10'? You don't have a pressure filter in here, do you?Anyways, I'll keep my eyes open. I think you would have to call a Horizon online outfit to get a quote on their pumps (it looks like the 10500 or 12500 models are what you're looking for). For the most part, your experience sounds typical with what I here from folks that run big submersibles - you just don't get the same lifespan as with external pumps. I've heard complaints about blown pumps leaking oil into the system, but I've never experienced that myself. Russell Watergardens (very overpriced, but just down the block from me) sells a submersible that would meet these specs:http://www.russellwatergardens.com/Pumps/hd12000.php#purchase
So at $830, you'd at least get a limited 2 year warranty. But I'm virtually certain this is a rebranded pump (Tsurumi? Atlantic Tidal?) that you could find cheaper.I have to say once again that the energy savings of going to an external pump really adds up quick...Got koi?-t
A swing check valve has an equivalent length of 25' of straight pipe, one elbow is a short radius (10 e.l.) , two are long radius (4 e.l.) and flexible black PVC pipe is smooth but no nearly as smooth as schedule 40 rigid PVC pipe. I have mechanical filter is the outfall/filter box, about 8" of course mesh, plus some media bags over those, but no pressure filter. I estimate pressure loss through the filters to be about 5 to 10 feet. I orginally had 75' of flex pipie, but have about 5 ft or so left over, so the "straight" run is actually 70 feet, but is not straight. Trenched in the ground under the main pond, but following the contours pretty closley. I found a website for Koi Ponds that has a flex pipe flow calculator and that for 200 gpm in 130 ft of 3" flex yielded about 15 ft of friction plus 5 ft of elevation. 150 gpm is 75% of 200 gpm, I think this is where our number s differ.
I'll look into the the PondMaster/Sure Pro. IF this pump fails again, I will be investing in a cast-iron, US made commercial grade pumps, like a Goulds.
Cool - I've wondered about the friction loss difference between sch. 40 (which is usually what I find published) and flex PVC in the past - that sounds about right with what I've experienced. 25' for a check valve (= 1 - 2' TDH) also sounds about right to me.Sorry I can't offer any better suggestions. You're really out on the edge of what folks do with sub. pumps. Nothing against it, you know - whatever works - it just doesn't leave a lot of room for alternatives! My current 2200 gal setup with ~ 10 - 15' head (bead filter looks to be ~5 - 10' TDH) probably has 50 pump options that would fall in the acceptable range. A 14k gallon tank at 150 - 200GPM must be good for a picture or two, eh? Funny thing - after I wrote that first response (Thursday/Friday?) my pump was stalled out Saturday morning. Brownouts in the night + a little impeller grit seized my little Sequence 4200. The motor was hotter than blazes and I thought it was cooked, so I lined up a replacement by that afternoon. Of course, I later pulled the wet end apart, cleaned up the scored impeller and it fired back up nicely. No big deal - the new pump will be a nice step up for the existing outdoor tank, and the old one will be the basis of my planned indoor wintering tank... I'm being punished for living a short drive from Pan Intercorp...-t
It probably helps here to return to the basics.
When you select a pump, the very first thing you need to do is define your use. Too much pump, too little pump, or the wrong pump will result in unhappy results. When a pump fails unexpectedly, or early in it's life, you need to learn what is really happening.
For example, today's pumps had performed quite well, for a decade. Then they started failing, and the original contractor was not able to solve the problem.
At first glance, it appeared that one, or both, pumps had bearing issues. Or. perhaps, some crud had fouled the impellers.
Well, there's no way to guess that one; you have to pull the pumps. Once we pumped out the pit, we found that a paving contractor had disposed of his sweepings and extra bits of asphalt by ... sweeping them into the pit. We then found some other material had, indeed, fouled the impellers. Yet, neither completely explained the problem.
What the primary problem turned out to be was material that had fouled the check valves.
So, look at your needs ... look at your pump selection .. and make sure everything else is working right. A cheap pump - or the most expensive one, for that matter - might not be the right pump.
I'm a little knowledgable in water systems and associated equipment, just not so much in the motor details.
It is still a work in progress. Dug the hole and got it running last July, first fish in August. The lay of the land creates some grade issues and we rebuilt the boulder wall with retaining wall block. The pic is when it was first filling.
Hi Tim:I completely forgot about that - I remember when you posted that picture the first time. That is an awesome setup - I'm jealous!I previously used an external pump in a much smaller (1500 - 2000 gal) but very similar arrangement. I went into the side of a Savio skimmer box with straight pipe and a Fernco fitting and then put in a 90° elbow and a check valve (to keep prime) sitting in the bottom of the reservoir. The pump sat just outside the skimmer, about 6" or so below grade to help keep it out of sight. A slick trick is to put another T in the line (near the pump inlet) with a quarter-turn valve and a terminal female garden hose adapter for easy priming. Once you get it primed the first time, the backflow valve in the skimmer box keeps you under prime for all but complete teardowns.I saw a posting a month or so back where a guy modified the filter screen on his Savio skimmer/filter. He got rid of the nylon mesh pad (which is a royal pain to clean) and instead riveted two sheets of stainless steel mesh over each face. It looked like it worked really well for mechanical filtration.I'll know it's time to die when I'm not looking forward to building my next pond....-t
"I'll know it's time to die when I'm not looking forward to building my next pond...."
Me, too! I'm already planning my next one. Learned a lot of lessons with this one. I'll learn a lot from next one I'm sure.
http://www.creativewatergardens.biz/ponds.html
I went here last week. great for ideas...
If it's built as a sewage pump I would think that it's intended to run for a few minutes and then be cycled off. Perhaps your application is not what this unit was designed for?
Scott.
The pump is intended for continuous operation as a "waterfall" pump. Was part of a pond kit. 200 gpm at 20' is how it operates, continuosly and did so for 9 of the last 12 months. This is not a sewage pump used in a pond. Just a little cheap. Got a replacement for $775. But I still want to rebuild this one and keep it as a spare/back-up.
You probably have the wrong pump for the job. A sump pump is not designed for continuous operation.
It's not really a sump pump, per sae. It is that style, i.e. vertical, cetrifugal, submersible with a vertical discharge.