33
172-65185A-08 (MC-COSR Multi-control Valve) 20 Nov 2014
Troubleshooting Chart (continued)
Problem Symptom
Cause
Remedy
The bypass valve is leaking Check; clean; replace
with a new valve if
necessary
The pilot valve seat or main
valve seat is damaged
Replace damaged parts
with new
Secondary
pressure
cannot be
adjusted or
increases
abnormally
(continued)
Upon closing
secondary side
valves, secondary
pressure abruptly
rises as high as
primary pressure
There is a build-up of dirt on
the pilot valve seat or main
valve seat
Clean; align; replace if
necessary
Occurs at low
steam demand
It is being operated below
the lower flow rate limit
Check the volume of
steam supply, replace
with a smaller diameter valve
There is too high a reduction
ratio (operated at below 10%
of the primary pressure)
Use a two-stage
reduction arrangement
Hunting never
stops
The selected model is
inappropriate for the service
conditions (specifications)
Check the model
selection, replace the
MC-COSR if necessary
Condensate is contained
check the piping
Hunting or
chattering
occurs
Chattering never
stops
The selected model is
inappropriate for the service
conditions (specifications)
Check the model
selection, replace the
MC-COSR if necessary
Abnormal
noises
Makes a high-
pitched noise
There is too high a
reduction ratio, the flow is
too great, or there is a high-
speed open / close valve
nearby
Use two-stage reduction
Check the flow rate, use
a larger size valve
Install the valve as far
away as possible
