Cashco DA4 User Manual
Page 13
IOM-DA4
13
SECTION IX
IX. TROUBLE SHOOTING GUIDE
When trouble shooting this regulator there are many possibilities as to what may be causing problems. Many times, the regu-
lator itself is not defective, but one or more of the accessories may be. Sometimes the pro cess may be causing diffi culties.
The key to effi cient trouble shooting is information and communication. The customer should try to be as precise as possible
in their explanation of the problem, as well as their understanding of the application and operating con di tions.
It is imperative the following information be provided by the customer:
•
Fluid
(with
fl uid properties)
• Range of outlet pressure
•
Range
of
fl ow rate
• Range of fl uid temperature
• Range of inlet pressure
• Range of ambient temperature
Pressure readings should be taken at every location where pressure plays a role - i.e., regulator inlet (as close as possible to
inlet port), regulator outlet (as close as possible to outlet port), etc.
Following are some of the more common complaints along with possible causes and remedies.
1. Erratic regulation, instability or hunting.
Possible Causes
Remedies
A.
Sticking of internal parts.
A.
Remove internals, clean, and if necessary, replace.
B.
Load changes are too quick for system.
B.
Convert to external sensing (if necessary) and install an orifi ce or
needle valve in external sensing line.
C. Oversized
regulator.
C. Check
actual
fl ow conditions; resize regulator for min i mum and maxi-
mum fl ow; if necessary, replace with smaller regulator.
D.
Too much variation in Inlet Pressure - P1.
D.
Consider use of a pilot for closer Outlet Pressure – P2
2. Erratic regulation, instability or hunting (liquid service).
Possible Causes
Remedies
A.
Air trapped under diaphragm.
A.
Install valve on external sensing port and bleed off air. (Install
regulator upside down to help prevent reoccurrence.
3. Downstream pressure will not reach desired setting.
Possible Causes
Remedies
A.
Supply pressure is down (confi rm on pressure
gauge.
A.
Increase supply pressure.
B. Undersized
regulator.
B. Check
actual
fl ow conditions; resize regulator for min i mum and maxi-
mum fl ow; if necessary, replace with larger regulator.
C.
Pressure loading system pressure restricted.
C1. Clean restriction or bleed orifi ces.
C2. Clean
fi lter(s).
C3. Clean loading pressure control device.
D.
Faulty loading pressure control device.
D.
Replace/repair loading pressure control device.
4. Diaphragm continually breaks (steam service regulators).
Possible Causes
Remedies
A.
Stem seals (14) which protect fl uorocarbon
elastomer in diaphragm assembly may have
deteriorated.
A.
Replace with new stem seals (14).
B.
Diaphragm nut (7) may not be torqued to
correct value.
B. Confi rm torque value in accordance with Section VII, F-7-i.
C.
Diaphragm too stiff causing it to crack.
C.
Follow proper preforming and air evacuation techniques during
diaphragm installation in accordance with Section VII, F-10.