MOYNO® 500 Pumps - Service Manual - 300 Series Motorized - 35650, 35651, 35652, 36750, 36751, and 36752 Models

Oct 25, 2026

Service manual content for MOYNO® 500 pumps (300 Series motorized) covering design features, installation requirements, and operating constraints for models 35650/35651/35652 and 36750/36751/36752. Specifications include materials for housing rotor, stator, seal, and motor shaft, along with electrical ratings, self-priming behavior, and limits for suction lift, discharge pressure, and temperature based on elastomer. Troubleshooting and disassembly steps emphasize safety precautions, correct wiring/rotation, pressure bleeding, and seal or component replacement guidance.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages5

Reading Time13 min

AccessFree to download

Design Features

Housing and Pump Components

Installation

Mounting Position and Pre-Wetting

Piping and Electrical Connections

Operation

Self-Priming and Lubrication

Pressure and Temperature Limits

Storage

Tables

Pump Data

Temperature Limits

Troubleshooting

Failure to Pump and Pump Overloads

Noisy Operation and Seal Leakage

Pump Will Not Prime

Pump Disassembly

Safety Precautions and Component Removal

Section: MOYNO® 500 PUMPS Page: 1 of 4 Date: March 1, 1998 SERVICE MANUAL MOYNO® 500 PUMPS 300 Series Motorized 35650, 35651, 35652, 36750, 36751, and 36752 Model DESIGN FEATURES Housing: Cast iron/316 SS Pump Rotor: AISI 416 stainless steel/ANSI 316 SS Pump Stator: NBR Seal: NBR (Nitrile) Motor Shaft: Mechanical (carbon/ceramic) Motor: 3 phase; 1-1/2 HP, 208/230/460V for Models 35650 and 35651; 2 HP, 230/460V for Models 36751 and 36750; 1 phase; 1-1/2 HP, 115/230V for Model 35652; 1 phase; 2 HP, 115/230V for Model 36752.60 Hertz, 1725 rpm, totally enclosed Note: Alternate elastomers available. Refer to Repair/ Conversion Kit Numbers, page 4. INSTALLATION Mounting Position. Pump may be mounted in any position. When mounting vertically, it is necessary to keep bearings above seals to prevent possible seal leakage into bearings. Pre-Wetting. Prior to connecting pump, wet pump elements and mechanical seal by adding fluid to be pumped into suction and discharge ports. Turn pump over several times in a clockwise direction to work fluid into pump elements. Piping. Piping to pump should be self-supporting to avoid excessive strain on pump housings. See Table 1 for suction and discharge port sizes of each pump model. Use pipe “dope” or tape to facilitate disassembly and to provide seal on pipe connections. Electrical. Follow the wiring diagram on the motor nameplate or inside the terminal box for the proper connections. The wiring should be direct and conform to local electrical codes. Check power connections for proper voltage. Voltage variations must not exceed + 10% of nameplate voltage. Motors do not have overload protection. To prevent damage to pump, pump rotation must be clockwise when facing pump from motor end. OPERATION Self-Priming. With wetted pumping elements, the pump is capable of 25 ft. suction lift with pipe size equal to port size. Be sure suction lines are air tight or pump will not self-prime. DO NOT RUN DRY. Unit depends on liquid pumped for lubrication. For proper lubrication, flow rate should be at least 10% of rated capacity. Pressure and Temperature Limits. See Table 1 for maximum discharge pressure of each model. Unit is suitable for service at temperatures shown in Table 2. Storage. Always drain pump for extended storage periods by removing bottom drain plug. To drain Model 36750, 36751 and 36752 remove suction housing bolts and loosen suction housing. Caution: Suction pressure should never be greater than discharge pressure. Table 1. Pump Data | Pump Model | 356 | 367 | | --- | --- | --- | | Suction Port (NPT) | 1-1/2 | 2 | | Discharge Port (NPT) | 1-1/4 | 1-1/4 | | Voltage Rating (VAC) | See Motor Name Plate
For Voltage Ratings | See Motor Name Plate
For Voltage Ratings | | Discharge Pressure (psig) (maximum) | 50 | 50 | NOTE: SSU = 5 x CP (approximate) specific gravity Table 2. Temperature Limits | Elastomer | Temperature Limits | | --- | --- | | *NBR | 10°-160°F | | *EPDM | 10°-210°F | | *FPM | 10°-240°F | *NBR = Nitrile EPDM = Ethylene-Propylene-Diene Terpolymer FPM = Fluoroelastomer Page 2 TROUBLE SHOOTING WARNING: Before making adjustments, disconnect power source and thoroughly bleed pressure from system. Failure to do so could result in electric shock or serious bodily harm. Failure To Pump. 1. Motor will not start: Check power supply. Voltage must be ± 10% of nameplate rating when motor isin locked rotor condition. 2. Motor runs and thermally kicks out: Check for excessive pressure. Increase ventilation to motor. Do not use less than \#14 wire size. 3. Stator torn; possible excessive pressure: Replace stator, check pressure at discharge port. 4. Flexible joint broken; possible excessive pressure: Replace joint, check pressure at discharge port. 5. Wrong rotation: Rotation must be clockwise when facing pump from motor end. Reverse the connections of any two line leads to the motor. 6. Excessive suction lift

FAQs

What materials are specified for the MOYNO® 500 pump housing, rotor, stator, and seals?

The manual specifies a cast iron/316 SS housing, an AISI 416 stainless steel/ANSI 316 SS rotor, an NBR stator, and an NBR (nitrile) seal. It also notes alternate elastomers may be available.

What key installation and electrical rules must be followed?

Mount the pump in any position while keeping bearings above seals when mounted vertically. Wire the motor per the wiring diagram on the motor nameplate or inside the terminal box, ensure voltage stays within ±10% of nameplate rating, and note that motors do not have overload protection.

How should troubleshooting address failure-to-pump, wrong rotation, or excessive pressure?

For a motor that will not start, check the power supply and locked rotor voltage at ±10% of nameplate. For wrong rotation, ensure clockwise rotation when facing the pump from the motor end and reverse any two line leads. For excessive pressure, check discharge pressure against the table maximum and inspect components such as stator or flexible joint as needed.

Oct 25, 2026

Upload by RizkyPratama_92