moyno Version 3, Service Manual

Page 4 
 
Moyno 2000 pumps have been designed for minimum 

stuffing box leakage when properly maintained. If leakage 
cannot be tolerated, then a mechanical seal should be used. 

3-5. G3 DRIVE ASSEMBLY ADJUSTMENT 

 
Ensure that the chain on the drive assembly has no bows. 

The chain tension can be adjusted by loosening or tightening 
the idler adjusting screw (E, F,fig. 4-10). 

 
The chain tension should be checked again and read-

justed after the first 20 hours of operation. 

 
The assembled torque limiter (3) and sprocket (4) on the 

bridge breaker assemblies are set at the factory to a reading 
of 540 lbs on a spring scale. (See fig. 3-1.)

If during opera-

tion the torque limiter slips, the torque should be checked 
and if necessary, reset. To check the torque limiter setting, 
use a spring scale as shown in the diagram with a properly 
sized chain to fit the sprocket (4). Attach the scale to the 
chain and pull, noting the value on the scale dial when the 
torque limiter slips. To adjust the torque, loosen the three 
capscrews on the torque limiter collar. Turn the collar clock-
wise to increase torque, or counter-clockwise to decrease it. 
Tighten capscrews until heads bottom and again check the 
torque setting. Repeat this process until the slipping point is 
within 5 lbs of the 540 lb value. When the correct torque is 
achieved, tighten setscrew to lock collar in position. 

Figure 3-1. Torque Setting Diagram 

4-1. MAINTENANCE 

Note: In this section, the first reference to each pump part 

will be followed by a number or a letter in parentheses 

( ). 

These numbers and letters are those used to iden-

tify the pump parts and hardware items in the foldout 
Exploded Views (fig. 4-7 or 4-10 as indicated). 

4-2. GENERAL 

 
The Moyno 2000 pump has been designed for a minimum 

of maintenance, the extent of which is routine adjustment 
and lubrication of packing. The pump is one of the easiest to 
work on, in that the main elements are very accessible and 
require few tools to disassemble. 

4-3. PACKING ADJUSTMENT 

Pumps.

 Packing gland nuts should be evenly adjusted so 

they are little more than finger tight. (See fig. 4-1.) Over-
tightening of the packing gland may result in premature 
packing failure and possible damage to the shaft and gland. 

 
When packing is new, frequent minor adjustments during 

the first few hours of operation are recommended in order to 
compress and seat the packing. 

 
 
1.  Upon initial start-up of the pump, adjust the gland nuts 

for a leakage rate of 1-2 drops per second until the packing 
has seated and adjusted to the operating temperature (ap-
proximately 10-15 minutes). 

 
2.  If leakage is excessive after 15 minutes of operation, 

tighten the gland nuts until a desired leakage rate is ob-
tained. 

CAUTION:  Do not tighten until zero leakage is obtained. 

Over-tightening of the packing gland may 
result in accelerated wear on the packing 
and damage to the shaft. In those situations 
where no packing leakage can be tolerated, 
consult your Moyno Authorized Service 

Representative. 

Figure 4-1. Cross Section of Stuffing Box 

 
Bridge Breaker.

 Packing for the bridge breaker is ad-

justed by means of cylindrical packing glands (25, fig. 4-10) 
which are threaded into the bearing retainers (28). Holes in 
the packing gland allow the use of a punch to rotate the 
gland. The packing is compressed by rotating the gland in a 
clockwise direction when viewed from the shaft end. 

4-4. PACKING 

REPLACEMENT 

 
When leakage can no longer be regulated by tightening 

the gland nuts, remove and replace the packing. The entire 
pump need not be disassembled to replace the packing. 
Briefly, replace as follows: 

 
1. Remove packing gland nuts (E, fig. 4-7), and slide 

gland (12) and slinger ring (11) back along drive shaft (4). 

 
2. Use a pair of packing extractors (fig. 4-2) to remove 

three packing rings (10), lantern ring halves (13) and three 
additional packing rings (10). 

 
3. Inspect surface of drive shaft for excessive wear or 

grooves due to packing rub. If shaft is worn, or is badly 
scored or grooved, it should be replaced.