moyno 35650, 35651, 35652, 36751, 36752 Service Manual

SERVICE MANUAL

MOYNO® 500 PUMPS

300 Series Motorized

35650, 35651, 35652, 36750, 36751, and 36752 Model

DESIGN FEATURES

Housing:
Pump Rotor:
Pump Stator:

Seal:
Motor Shaft:

Motor:

Note: Alternate elastomers available. Refer to Repair/ Conversion
Kit Numbers, page 4.

Cast iron/316 SS

AISI 416 stainless steel/ANSI 316 SS

NBR

NBR (Nitrile)

Mechanical (carbon/ceramic)

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

Section:

MOYNO

®

500 PUMPS

Page: 1 of 4
Date: March 1, 1998

INSTALLATION

Mounting Position.

position. When mounting vertically, it is necessary to
keep bearings above seals to prevent possible seal
leakage into bearings.

Pre-Wetting.

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.

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.

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.

Piping to pump should be self-supporting to

Follow the wiring diagram on the motor

Pump may be mounted in any

Prior to connecting pump, wet pump

OPERATION

Self-Priming

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.

for lubrication. For proper lubrication, flow rate should
be at least 10% of rated capacity.

Pressure and Temperature Limits.

maximum discharge pressure of each model. Unit is
suitable for service at temperatures shown in Table 2.

. With wetted pumping elements, the

Unit depends on liquid pumped

See Table 1 for

Storage.

periods by removing bottom drain plug. To drain
Model 36750, 36751 and 36752 remove suction
housing bolts and loosen suction housing.

Always drain pump for extended storage

Caution: Suction pressure should never be

greater than discharge pressure.

Table 1. Pump Data

Pump Model

Suction Port
(NPT)
Discharge Port
(NPT)
Voltage Rating
(VAC)

Discharge Pressure
(psig) (maximum)

NOTE: SSU = 5 x CP (approximate)

specific gravity

356 367

1-1/2 2
1-1/4 1-1/4

See Motor Name Plate

For Voltage Ratings

50 50

See Motor Name Plate

For Voltage Ratings

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.

Motor will not start: Check power supply. Voltage

1.

must be ± 10% of nameplate rating when motor is
in locked rotor condition.

Motor runs and thermally kicks out: Check for

2.

excessive pressure. Increase ventilation to motor.
Do not use less than #14 wire size.

Stator torn; possible excessive pressure: Replace

3.

stator, check pressure at discharge port.

4. Flexible joint broken; possible excessive
Replace joint, check pressure at discharge port.
Wrong rotation: Rotation must be clockwise when

5.

facing pump from motor end. Reverse the
connections of any two line leads to the motor.

Excessive suction lift or vacuum.

6.

Pump Overloads.

Excessive discharge pressure: Check pressure at

1.

discharge port for maximum ratings given in Table
Fluid viscosity too high: Limit fluid viscosity to 100

2.

CP or 500 SSU.

Noisy Operation.

Excessive suction lift or vacuum: Maximum suction

1.

lift is 25 feet for water.
Suction line too small: Check pipe size. Be sure

2.

lines are free from obstructions.
Pump cavitates: Pump speed is 1725 rpm.

3.

Viscosity of fluid should not exceed 100 CP or 500
SSU.

Flexible joint worn: Replace joint. Check pressure

4.

at discharge port.
Insufficient mounting: Mount to be secure to a firm

5.

base. Vibration induced noise can be reduced by
using mount pads and short sections of hose on
suction and discharge ports.

Seal Leakage.

Leakage at startup: If leakage is slight, allow pump

1.

to run several hours to let faces run in.
Persistent seal leakage: Faces may be cracked

2.

from freezing or thermal shock. Replace seal.

Pump Will Not Prime.

Air leak on suction side: Check pipe connections.

1.

pressure:

PUMP DISASSEMBLY

WARNING: Before disassembling pump,

disconnect power source and
thoroughly bleed pressure from
system. Failure to do so could result
in electric shock or serious bodily
harm.

Disconnect power source.

1.

Remove suction and discharge pip ing.

2.

Remove screws (112) holding suction housing (2)

3.

to discharge housing (1). Remove suction housing
(2) and stator (21).

Rotor (22) can be detached from flexible joint (24)

4.

by using a punch to remove rotor pin (45). Support
joint when removing pin.

Flexible joint (24) can be removed from motor

5.

shaft by using a punch through the discharge port
to remove shaft pin (46).

Carefully slide mechanical seal (69) off motor

6.

shaft.
Remove discharge housing (1) from motor (70) by

7.

removing screws (112A and 112C) and washers
(215).

Carefully pry seal seat out of discharge housing

8.

(1). If any part of mechanical seal (69) is worn or
broken, the complete assembly should be
replaced. Seal components are matched parts and
not interchangeable.

Remove slinger ring (77).

9.

PUMP ASSEMBLY

Replace slinger ring (77).

1.

Attach discharge housing (1) to motor (70)

2.

lock washers (215) and body screws (112A).
Install mechanical seal (69) using the following

3.

procedures:

Clean and oil sealing faces using light oil (not

a.

grease).

Caution: Do not use oil on EPDM parts.

Substitute glycerin or soap and water.

Oil the outer surface of seal seat, and push

b.

assembly over motor shaft into the bore of the
discharge housing (1) seating it firmly and
squarely.

After cleaning and oiling the shaft, slide the

c.

seal body along the shaft until it meets the seal
seat.

Install seal spring and spring retainer on shaft.

d.

On Model 367, position seal spacer (69A) on

4.

motor shaft with slots away from seal (69).
Pin flexible joint (24) to motor shaft with shaft pin

5.

(46) using a punch through the discharge port.
Pin rotor (22) to flexible joint using rotor pin (45).

6.

Support joint while installing pin.
Slide stator (21) on rotor (22) carefully

7.

stator flange in housing groove
Secure stator (21) and suction housing (2) to

8.

discharge housing (1) using screws (112).

9.

Proceed as in installation instructions.

.

using

locating