In almost all cases, choosing a non-submersible over a submersible one is the best choice for several reasons
Power wise, non-submersibles consume far less energy so running costs are lower. The motor also has a much longer life span so replacement costs are also lower
Non-submersible pumps do however cost more initially and require more effort to setup
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Above or Below Pond Level ?
First you need to decide whether the pump will be installed above or below pond level - below pond level is likely in the ground. There are advantages and disadvantages for each setup, unless you can install above ground and below pond level which is the ideal
In an above pond level scenario, the pump box will be easier to install. As many in-line pumps do not have the ability to self prime, the downside is getting the pump "primed". Prime simply means getting the pump intake line and some of the outake line filled with water which is required for it to run. Priming pots do work to a certain extent with non-priming pumps but I have yet to find a model which I like. The pot lids are difficult to remove and they require frequent cleaning in most setups because of their small size. If you do not clean them regularly your pump flow will decrease and can eventually stop. Priming pots were really designed for swimming pool applications although some larger, pond specific units are now on the market
The major advantage of above ground setup is protection from flooding . If the pump somehow develops a leak, the water will likely run away from the pump. In a below ground setup however, the pump box cavity the leaking pump is housed in will eventually fill with water and submerse the pump, likely ruining it in the process
In a below grade setup, the pump is under the level of the water so the intake and outake lines will automatically fill via gravity. This eliminates the hassles of pump priming. From an aesthetics viewpoint, the pump boxes are also well hidden when they are below ground
The grade of the land also has to be taken in to consideration in order to avoid potential flooding problems from rain and runoff etc. The reality is I have only seen a couple of cases where a pump was flooded and ruined in a below grade installation so that is often the route we take |
Flex Pipe and Rubber Couplers
If you are not well experienced, dry fitting is highly recommended before you commit to gluing. Make sure you leave provision so that you can easily remove the pump at the later date for servicing and/or replacement. If you are below grade, this means incorporating gate valves or you will have a flooded pump box. Flex hose and rubber couplers make this process simple - forget the anti-kink and poly fittings which are a nightmare to work with
I set up most pumps by gluing a small piece of pipe in each of the in and out pump fittings. Then, I use a rubber coupler and flex hose. Although more expensive than pipe, flex is a joy to work with. No elbows are required, it is flexible and easy to lay out and it can take freezing much better than rigid ABS or PVC - it is simply the superior choice. Make sure to purchase the rubber couplers that come with stainless steel clamps/bolts |
There a few things to consider here. First, you never want to restrict the intake of a pump. If you require less flow, restrict the outake with a ball valve - this simply creates a greater head loss and subsequent reduction in flow
It's important to match the diameter of the pumps in and out with the same piping size. If the pump has intake and outake diameter's of 1.5 inches then use pipe of the same size. 1.5" is a typical bore for pumps up to 3,000 g.p.h.
Head loss calculation charts are worth looking at so you have a rough idea of the basics of how your piping will reduce the flow rate of your setup
Perplexingly, most larger submersible pumps that purport a 3,4 or 5k flow rate, all come with the same small elbowed connector. This
obviously effects the throughput of the pump |
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It is certainly worth the minimal expense and effort to mount your pumps on anti vibration pads. The pads increase the longevity of the motors by absorbing vibrations thereby reducing engine wear
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Pump boxes can get complicated and space always seems to be tight. Here we have 2 pumps (one with 3 jet return controls valves) and an aerator. Expect to spend
several hours putting together a box like this one
 About as incorrect
as you can get
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Many people think that running their pump on 240 volts will cost less in hydro. Sure, it sounds correct, at double the voltage, the amperage is 50% so that's better right? I even repeated this as fact to people, having heard it so much myself. After just completing an interesting Electrical Fundamentals course (winter 2004) I now know better
When you examine the power (watts) calculation, the amount of KWHr's (kilowatt hours) ends up being the same whether your pumped is connected to a 120 or 240 volt supply
P (power in watts) = I (Amperage in amps) x V (Voltage in volts)
So if you have a massive 9 amp pump on 120V you have P = 9A x 120V P = 1080 W
If you decide to get efficient and run this pump on 240V P = 4.5A x 240V P = 1080 Watts
So in the end, regardless of voltage, the pump ends up costing the same money to operate per kilowatt hour |
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