D Series Centrifugal Pumps

MTH Pumps D Series Centrifugal Pumps

D Options

  • Capacities to 240 GPM

  • Heads to 360 Feet

  • Horizontal Close Coupled

MTH D Series

Close-coupled centrifugal pumps represent the most economical, high performance alternative for high flow applications involving low to moderate pressures (heads to 360 feet).
By combining the latest concepts in centrifugal pump design with precision computer controlled manufacturing, the D Series pumps deliver high efficiency operation even at low NPSH. Costs are controlled by efficient manufacturing processes and highly optimized pump designs. Maintenance costs are kept to a minimum by combining an easily serviceable design with the use of high quality components to provide long life.


Standard casing construction of all units is ASTM A48 Class 30 cast iron. All bronze casings are currently available in the D71 and D91 Series only. In all models, the discharge can be rotated to any 90° position and NPT suction and discharge ports are standard. Back pull out design allows the pump to be serviced without disturbing the piping. The volute was designed to maximize hydraulic efficiency.

Mechanical Seal

Type 21 Buna-N seal is rated to 225°F and pressures to 175PSI and is used on the D51, D61, D71, and D91 Series. The carbon seal face mates with a ceramic seat providing years of trouble-free service. The seal cooling jacket high temperature version of the D51 unit uses a Type 21 Viton seal that is rated to 400°F with pressures to 175PSI. Alternate seals available upon request.


The hydraulic design of the enclosed impellers maximizes pressure and capacity while minimizing horsepower. All standard D Series models feature a cast bronze impeller, while the high temp jacketed version of the D51 utilizes a vacuum cast enclosed impeller made of CDA87500 silicon bronze for high temperature resistance. This high temp D51 also features a pressed-on throttle bushing which fits snugly into the motor bracket to restrict hot fluid circulation into the cooled seal cavity.

Motor Bracket

Standard construction for motor backets is ASTM A48 Class 30 cast iron, while the D71 and D91 Series are also available in bronze. Precise machining of the D Series motor brackets allows easy assembly of the pumps. A 1/8" NPT hole is provided in the motor bracket for a seal flush line if desired. The D51 also comes in a high temp version that has a motor bracket with a cast-in seal cooling jacket which allows fluids up to 500°F to be pumped without damage to the mechanical seal or the motor. The seal chamber is specially machined to allow minimal hot liquid circulation, which keeps the area cool. The water jacket has 1/2" NPT ports every 90° for easy water line connections.


The NEMA JM frame motor found on the D71 and D91 Series utilizes a high carbon steel shaft. The NEMA 56J frame motors used on the D51 and D61 Series utilize a 416 stainless steel shaft. The motor's heavy duty ball bearings withstand heavy axial and radial thrust loads. Standard enclosure type is open drip-proof with alternatives available on request.

D-Series Self-Priming Pump Engineering Specifications

For a copy of the D Series Manual and D Series Parts List, go to the Product Support Page.

Download a printable version of the D Series Product Bulletin in .pdf format.

Download the complete D Series Series Section (curves and dimensions) from the Standard Products Catalog.

If you do not have the Adobe Acrobat Reader, click here Click here to go to Adobe and download Acrobat to download the most recent version from Adobe.

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