moyno Version 3, Service Manual

 
For maximum rigidity and lower noise levels the base 

plate should be grouted to the foundation after the anchor 
bolts have been evenly tightened. A good grade of non-
shrink grout is recommended. The spaces between the base 
plate and the foundation around the shims should also be 
filled with grout. Allow the grout to dry according to manufac-
turer’s instructions, then fully tighten the anchor bolts. 

2-7. SHAFT ALIGNMENT 

 
Although the base-mounted units supplied by Robbins & 

Myers are leveled with respect to the base before shipping, 
most of the larger pump and driver units are shipped with the 
flexible coupling disconnected. 

 
After the base has been bolted down to the foundation, 

check the following conditions: 

2-8. On coupling connected units, 

be sure that the pump 

and driver shafts are realigned before the coupling is con-
nected. Care should be exercised to ensure that all compo-
nents are level and mounted in a direct line. 

 
Check gap between coupling halves (refer to coupling 

manufacturers recommendations). Adjustment can usually 
be accomplished by loosening the mounting bolts on either 
the pump or driver and moving the loosened component into 
alignment with the fixed component. On couplings with equal 
diameter hubs, it may be helpful to lay a straight edge axially 
across the coupling halves to check alignment. 

2-9. On belt drive units,

 check to ensure that sheaves or 

sprockets are in alignment. Check belts for proper tension. 
Tension requirements will vary with type of belt, center dis-
tances, and belt speeds. Consult belt manufacturer for spe-
cific recommendation. 

2-10. WATER FLUSH OF PACKING 

 
The packing may be either grease lubricated through a 

grease fitting in the stuffing box or have plumbing connected 
to the housing to allow a water flush. Packing is not grease 
lubricated at the factory prior to shipping. 

 
When the material being pumped is abrasive, water flush-

ing the packing is recommended to extend shaft life. 

 
Clean water can be injected through a 1/8” NPT tapped 

hole that normally houses the grease fitting for lubricating the 
packing. The water can be permitted to leak axially along the 
shaft in either direction or can be removed from the second 
tapped hole in the stuffing box. In both cases, the discharge 
from the stuffing box should be throttled slightly to maintain 
10-15 PSI higher pressure in the stuffing box than is present 
in the suction housing. (See fig. 2-2.) Flow rate should be 
approximately 1/2-2 gpm. 

 
If mechanical seals are to be used on the unit, consult the 

seal manufacturers’ instructions for seal flush requirements. 

3-1. OPERATION 
 
3-2. INITIAL CHECK 

 
Before putting the pump into operation, the following items 

should be checked to ensure that each piece of equipment is 
installed correctly: 

—

  Pump, driver, coupling or sheave alignment. 

Page 3 

Figure 2-2. Typical water flush arrangement for units 
with packing includes strainer valve (1), sight flow meter 
(2), pressure regulating valve (3), solenoid valve (4), 
pressure gauge (5), and needle valve (6). 
 

 — 

Electrical 

connections 

—  Gauges and other instruments. 

—  Water flush connection to the stuffing box. 

 — 

Pump 

rotation. 

Normal rotation is indicated on the 

nameplate on the bearing housing. 

—  All valves should be open on both suction and 

discharge sides of pump. 

CAUTION:  This is a positive displacement pump. Do not 

operate it

against a closed valve. 

 
3-3. START-UP 

CAUTION: DRY OPERATION IS HARMFUL TO THE PUMP! 
 

Never allow the pump to operate without liquid, 
as dry operation will cause premature wear of 
the stator and possible damage. The stator is  
lubricated by the liquid which is pumped.

 
1.  Before operating the pump for the first time, fill it with 

liquid (the pipe plug tap on the suction housing may be used 
for filling). If the liquid to be pumped is highly viscous, dilute 
it before filling the pump. The liquid fill-up will lubricate the 
stator for the initial start-up. 

Note:  If the pump is shut down temporarily, enough liquid 

will remain in the system to provide lubrication upon 
restarting. It is advisable to maintain the suction pip-
ing at a higher elevation than the centerline of the 
pump in order to contain some liquid in the pump at 
time of shutdown. 

 
2.  Once the pump has been filled with liquid, check for di-

rection of pump rotation by momentarily starting and stop-
ping the drive. Check rotation arrow on pump nameplate for 
correct rotation. 

 
3.  If applicable, turn on the seal water to packing. 
 
4. Start pump. 

3-4. PACKING LEAKAGE 

 
A packed stuffing box is designed to control leakage, not 

stop it completely. Leakage is generally necessary to reduce 
friction and dissipate heat. The amount of leakage necessary 
will depend on the fluid pumped, the installation, and pump 
speed and type. Refer to Section 4-3 for packing adjustment.