MOYNO 500 PUMPS - 200 SERIES - SERVICE MANUAL - 20302, 20402, 20501, 20502, 22001, 22002, 23201, AND 23203 MODELS

Oct 25, 2026

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Service manual for MOYNO 500 pumps, 200 series, covering models 20302, 20402, 20501, 20502, 22001, 22002, 23201, and 23203. Provides design features (materials and seals), installation guidance (mounting orientation, pre-wetting, piping, drive alignment and rotation), and operation limits including maximum speed 1750 rpm, suction lift behavior, dry-run prohibition, and pressure/temperature boundaries by elastomer. Includes troubleshooting for failure to pump, overloads, noisy operation, and seal leakage, plus pump disassembly and assembly warnings and steps.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

DESIGN FEATURES

INSTALLATION

OPERATION

TROUBLE SHOOTING

PUMP DISASSEMBLY

PUMP ASSEMBLY

Section: MOYNO® 500 PUMPS Page: 1 of 4 Date: December 1, 1999 SERVICE MANUAL MOYNO® 500 PUMPS 200 SERIES 20302, 20402, 20501, 20502, 22001, 22002, 23201, AND 23203 MODELS DESIGN FEATURES Housing: Stainless steel or aluminum Pump Rotor: Phenolic & AISI 316 stainless steel Pump Stator: NBR (Nitrile) Shaft: AISI 316 stainless steel Bearings: Prelubricated, fully sealed ball bearings Seal: Mechanical (carbon/ceramic) Note: Alternate elastomers available. Refer to Repair/Conversion kit numbers, page 3. 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 shaft over several times in a clockwise direction to work fluid into elements. Piping. Piping to pump should be self-supporting to avoid excessive strain on pump housings; 3/8” NPT pipe used on 203, 204, 205 and 220 Models, and 1/2”NPT pipe used on 232 Models. Use pipe “dope” or tape to facilitate disassembly and to provide seal. Drive. On belt driven units, adjust belt tension to point of non-slip. Do not overtighten. On direct drive units, coupling components should be aligned and spaced at least 1/16” apart. Pump rotation must be clockwise when facing shaft to prevent rotor unscrewing from shaft. Check direction of rotation before startup. Maximum speed is 1750 rpm. OPERATION SeIf-Priming. With wetted pumping elements, the pump is capable of 25 feet of suction lift when operating at 1750 rpm with pipe size equal to port size. Be sure suction lines are air tight or pump will not selfprime. Note: Self-priming capabilities will vary depending on fluid viscosity. DO NOT RUN DRY. Unit depends on liquid pumped for lubrication. For proper lubrication, flow rate should be at least 10% of rated capacity at a given rpm. Pressure and Temperature Limits. Maximum discharge pressure is 40 psig. Unit is suitable for service at temperatures shown in Table 1. Storage. Always drain pump for extended storage periods using pipe plug in pump body. Table 1. 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 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. Replace belt or coupling guards before reconnecting power. Failure To Pump. 1. Belt or coupling slip: Adjust belt tension or tighten setscrew on coupling. 2. Stator torn; possibly excessive pressure: Replace stator. Check pressure at discharge port. 3. Wrong rotation: Rotation must be clockwise when facing shaft. 4. Threads in rotor or on shaft stripped: Replace part. Check for proper rotation. 5. Excessive suction lift or vacuum. Pump Overloads. 1. Excessive discharge pressure: Check discharge pressure for 40 psig maximum or obstruction in discharge line. 2. Fluid viscosity too high: Limit fluid viscosity to 20,000 CP or 100,000 SSU. 3. Suction pressure should never be greater than discharge pressure. Page 2 | Viscosity CP | Limit RPM | | --- | --- | | 1-300 | 1750 | | 300-1,000 | 1200 | | 1,000-2,000 | 700 | | 2,000-5,000 | 350 | | 5,000-10,000 | 180 | | 10,000-20,000 | 100 | 4. Insufficient motor HP: Check HP requirement. Noisy Operation. 1. Starved suction: Check fluid level, size of piping, and obstructions in pipe. 2. Bearings worn: Replace parts. 3. Insufficient mounting: Mount securely. Reduce vibration induced noise by using a short section of hose on discharge piping. Seal Leakage. 1. Leakage at startup: If leakage is slight, allow pump to run several hours to let

FAQs

What are the key design features and materials for MOYNO 500 pumps (200 series)?

The housing is stainless steel or aluminum; the pump rotor uses phenolic & AISI 316 stainless steel. The pump stator is NBR (nitrile), the shaft is AISI 316 stainless steel, bearings are prelubricated fully sealed ball bearings, and the seal is a mechanical carbon/ceramic type.

How should the pump be installed and started to ensure proper operation?

The pump may be mounted in any position, but when mounted vertically bearings must remain above seals to prevent seal leakage. Pre-wet pump elements and the mechanical seal before connecting, ensure self-priming by keeping suction lines air-tight, align drive components for direct drive units, and confirm clockwise rotation when facing the shaft.

What should be checked when the pump fails to pump or primes incorrectly?

For failure to pump, check belt/coupling slip, stator damage and discharge pressure, wrong rotation, and stripped rotor/shaft threads, and verify proper rotation direction. For not priming, inspect for air leaks on the suction side and check pipe connections.

Oct 25, 2026

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