172-65174MA-11 (COSR Pressure Reducing Valve) 16 Feb 2022
24
Troubleshooting
When disassembling or removing the product, wait until the internal
pressure equals atmospheric pressure and the surface of the product
has cooled to room temperature. Disassembling or removing the
product when it is hot or under pressure may lead to discharge of fluids,
causing burns, other injuries or damage.
CAUTION
This product is shipped after stringent checks and inspection and should perform its
intended function for a long period of time without failure. However, should there be
any problem encountered in the operation of the COSR, consult the troubleshooting
guide below.
Problems are classified as follows:
1. The secondary pressure does not increase.
2. The secondary pressure cannot be adjusted or increases abnormally.
3. Hunting (fluctuation of the secondary pressure) occurs.
4. Chattering (a heavy mechanical noise) occurs.
5. Abnormal noises.
Major causes for the above problems are usage under non-specified conditions (out
of specification), insufficient pressure or flow rate, and clogs by dirt and scale.
To ensure performance for a long period of time, it is recommended that the
“Acceptable Operating Range”, “Correct Usage of the COSR Pressure Reducing
Valve” and “Adjustment” sections be reviewed
.
Problem
Symptom
Cause
Remedy
The secondary
pressure does
not rise
The body is not
warm
No steam is being
supplied or the inlet
valve is closed
Check the valves and
piping
The body is warm,
but the pressure
does not increase
The entrance to the
screens or strainer is
clogged
Clean or blow down
The secondary
pressure
cannot be
adjusted or
increases
abnormally
Adjustment is
difficult, and set
pressure varies
The pilot screen is
clogged
Clean
There is insufficient
steam flow
Check the flow, replace
the COSR if necessary
The piston is clogged
with dirt
Clean
Check the piston ring
The piston ring is worn
Replace with a new piston
ring
There is a build-up of
dirt on the sliding
surfaces of the piston,
pilot or main valve
Clean
Flow rate exceeds rated
flow rate
Check the flow rate,
replace with a larger size
The adjustment screw
has seized
Replace with a new
adjustment screw
Continued on next page
