Direct Drive Pumps
Direct drive pumps have been the driving force and the contractors #1 choice for pond installations for many years. These powerful direct drive submersible pumps are capable of high working head heights and have been the workhorse of the pond industry. A direct drive pump can usually be identified by the following characteristics:
- The pump impeller is attached to the motor with a drive shaft with only the impeller emerging from the pump motor body;
- Pump will typically have a high working dynamic head (although low head direct drive pumps are available);
- Pump allows passage of larger solid objects;
- Pump impeller has curved vanes allowing for maximum flow and power;
- Pricing varies pending quality of pump but is generally higher than the magnetic drive pumps.
Direct dive pumps are available from flow ranges of about 100 GPH to well over 12,000 GPH. Direct drive pumps contain inner seals that keep water from entering through the drive shaft inside the pump motor. The curved blades of the impeller maximize the flow of the water passing through and electrical consumption varies by pump according to size and manufacturer design. Direct drive pond pumps are most often used when a large volume of water is needed or flow is needed at greater heights than a magnetic drive can handle.
High flow capacity and capabilities of reaching higher waterfalls or features make the direct drive pump the continued choice by many professional installers. Better designs have created more energy efficient direct drive pumps although this varies by manufacturer. With typical pumps ranging from 1/5 HP (Horse Power) to 2 HP a wide variety of water features can be covered effectively. The direct drive nature of these pumps coupled with the impeller design allow for many solids to easily pass through without damaging the pump. Some direct drive pumps advertise the ability to pass up to 2˝ solids while 1 to 1.25˝ are the norm. Many manufacturers use double mechanical seals as this helps keep the water out and extends the life of the pump. On the higher end of these pumps they will often contain automatic shutoff switches to prevent overheating in the event of a low water situation.
Mechanical seals are the weak point of direct drive pumps. If the seals leak water enters the electrical motor and the pump will short out and be ruined. Quality varies widely among the many direct drive pumps on the market and due diligence is required on the part of the pond professional in order to determine which will best meet the required application and the budget available. Some direct drive pump models have only single seals to protect the pump motor but most manufacturers have moved to at least double seals. Direct drive pumps are filled with a non-toxic oil that if it leaks into the pond is not a safety concern but is disturbing to consumers. Many so-called “oil free” pumps still contain some amounts of oil.
Electrical consumption on direct drive pumps also varies widely by size and even by manufacturer. Energy consumed can be as low as around 300 watts for a 1/2 HP pump to over 2000 watts for a 2 HP motor.
Direct Drive Pump Trends in the Pond Industry
Costs of materials continue to climb for manufacturers resulting in increased wholesale and retail prices. Direct drive pumps are thought by many to have lost market share to the newer Hybrid pumps, which will be discussed next. However the manufacturers interviewed for this article contend that direct drive pump sales remain strong and given the limitations on alternative pumps the market is expected to be stable for many more years. Some manufacturers are reporting a strong year over last sales increase for direct drive pumps. Future advances to the direct drive pumps include the possibility of adding variable speed controls to further increase energy efficiency.
The advantage to using a direct drive pond pump is that they are more powerful and push high head (head= height where the pump is located to the top of the water feature) heights with ease compared to mag drive pond pumps. If your water feature has a tall waterfall or long stream in the design a direct drive pond and waterfall pump should be considered.
To Determine the Size of the Pond Pump Needed:
First, Identify the purpose(s) of the pond pump. For example, is the pond pump responsible for powering a pond filter, a fountain in or around the pond, and/or