Hydrotech Classic Series Stenner Basic Service Manual - Manual (Page 19)

18 Maintenance Basics – Tube
Frozen rollers in roller assembly (wear part)
Chemical intrusion.
A cracked pump head housing
Wear, chemical exposure, or incompatibility.
Corrective Action
1. Pump head housing and roller assembly must be cleaned
and wiped free of chemical residue or replaced if corroded
or cracked. Rollers need to turn freely but without
rocking/tilting from side to side.
2. Replace roller assembly and/or cracked housing.
NOTE
Additional information
Normal roller wear can cause a lack of output as a
result of the rollers’ inability to fully squeeze the
tube. The wear is generally in the bore of the roller. To
check for roller bore wear, hold each roller (at the top
and bottom) between your thumb and index finger. If it
rocks back and forth, replace the roller assembly.