2
Flow Direction
The flow through the 100-01 Hytrol Valve can be in one of two
directions. When flow is “up-and-over the seat,” it is in “normal”
flow and the valve will fail in the open position. When flow is “over-
the seat-and down,” it is in “reverse” flow and the valve will fail in
the closed position. There are no permanent flow arrow markings.
The valve must be installed according to nameplate data.
BRIDGEWALL INDlCATOR
Normal Flow Reverse Flow
Troubleshooting
The following troubleshooting information deals strictly with the
Model 100-01 Hytrol Valve. This assumes that all other compo-
nents of the pilot control system have been checked out and are
in proper working condition. (See appropriate sections in
Technical Manual for complete valve).
Three Checks
The 100-01 Hytrol Valve has only one moving part (the diaphragm
and disc assembly). So, there are only three major types of prob-
lems 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.
Closed isolation valves in control system, or in main line.
Lack of cover chamber pressure.
Diaphragm damaged. (See Diaphragm Check.)
Diaphragm assembly inoperative.
Corrosion or excessive scale build up on valve stem.
(See Freedom of Movement Check)
Mechanical obstruction. Object lodged in valve.
(See Freedom of Movement Check)
Worn disc. (See Tight Sealing Check)
Badly scored seat. (See Tight Sealing Check)
Closed upstream and/or downstream isolation
valves in main line.
Insufficient line pressure.
Diaphragm assembly inoperative. Corrosion or excessive
buildup on valve stem. (See Freedom of Movement Check)
Diaphragm damaged. (For valves in "reverse flow" only)
After checking out probable causes and remedies, the following three checks can be used to diagnose the nature of the
problem before maintenance is started. They must be done in the order shown.
Open Isolation valves.
Check upstream pressure, pilot system, strainer, tubing, valves, or needle
valves for obstruction.
Replace diaphragm.
Clean and polish stem. Inspect and replace any damaged or badly eroded
part.
Remove obstruction.
Replace disc.
Replace seat.
Open isolation valves.
Check upstream pressure. (Minimum 5 psi flowing line pressure differential.)
Clean and polish stem. Inspect and replace any
damaged or badly eroded part.
Replace diaphragm.
Fails to Close
Fails to Open
CAUTION:
Care should be taken when doing the troubleshooting checks on
the 100-01 Hytrol Valve. These checks do require the valve to
open fully. This will either allow a high flow rate through the
valve, or the downstream pressure will quickly increase to the
inlet pressure. In some cases, this can be very harmful. Where
this is the case, and there are no block valves in the system to
protect the downstream piping, it should be realized that the
valve cannot be serviced under pressure. Steps should be
taken to remedy this situation before proceeding any further.
(cast into side of valve body)
SYMPTOM PROBABLE CAUSE REMEDY
Recommended Tools
1. Three pressure gauges with ranges suitable to the instal-
lation to be put at Hytrol inlet, outlet and cover connections.
2. Cla-Val Model X101 Valve Position Indicator. This pro-
vides visual indication of valve position without disassembly
of valve.
3. Other items are: suitable hand tools such as screw-
drivers, wrenches, etc. soft jawed (brass or aluminum) vise,
400 grit wet or dry sandpaper and water for cleaning.
All trouble shooting is possible without removing the valve from the
line or removing the cover. It is highly recommended to permanently
install a Model X101 Valve Position Indicator and three gauges in
unused Hytrol inlet, outlet and cover connections.
