Cla-Val 90-21 Technical Manual - Manual (Page 8)

Hytrol Valve
Description
The Model 100-01 Hytrol Valve is the main valve for the
CIa-VaI Model 90-21 Pressure Reducing Control Valve.
It is a hydraulically operated, diaphragm-actuated, globe
or angle pattern valve.
This valve consists of three major components; body, di-
aphragm assembly, and cover. The diaphragm assembly
is the only moving part. The diaphragm assembly
uses a diaphragm of nylon fabric bonded with synthetic
rubber. A synthetic rubber disc, contained on three and
one half sides by a disc retainer and disc guide, forms a
seal with the valve seat when pressure is applied above
the diaphragm. The diaphragm assembly forms a sealed
chamber in the upper portion of the valve, separating op-
erating pressure from line pressure.
INSTALLATION/OPERATION/MAINTENANCE
MODEL
100-01 UL
Troubleshooting
The following trouble shooting information deals strictly with
the “Hytrol Valve.” This assumes that everything but the
main valve itself has been completely isolated, i.e., each
part of the control system is hydraulically blocked from the
Hydro valve. All troubleshooting is possible without remov-
ing the valve from the line or removing the cover.
The Hydro valve has only one moving part (the diaphragm
and disc assembly). So, there are only three major types of
problems to be considered:
First: Valve is stuck - that is the diaphragm assembly is not
free to move through a full stroke either from open to close
or vice versa.
Second: Valve is free to move and can’t close because of
a worn out diaphragm.
Third: Valve leaks even though it is free to move, and the
diaphragm isn’t leaking.
SERVICE SUGGESTIONS
SYMPTOM PROBABLE CAUSE REMEDY
Fails to Lack of cover chamber Check upstream
close pressure pressure, X46 or
tubing for obstruction.
Diaphragm damaged. Replace diaphragm
(See Diaphragm Check,
Steps 1-3)
Corrosion or excessive Clean and polish stem
scale build up on valve Inspect and replace
stem. (See Freedom of any damaged or badly
Movement Check, eroded part.
Step 4.)
Mechanical obstruction. Remove obstruction.
Object lodged in valve.
(See Freedom of Move-
ment Check, Step 4.)
Worn Disc Replace disc.
(See Tight Seating
Check, Step 4.)
Fails to Closed upstream and/ Open Valves
open or downstream isolation
valves in main line.
Insufficient line pressure. Check pressure.
Corrosion or excessive Clean and polish stem
scale build up on valve Inspect and replace
stem. (See Freedom of damaged or badly
Movement Check Step 4) eroded part.
For Model 90-21 UL Listed Pressure
Reducing Valve