Cashco DA1 - Manual (Page 12)

IOM-DA1 12
SECTION VIII
VIII. TROUBLE SHOOTING GUIDE
When trouble shooting this regulator there are many possibilities as to what may be causing problems. Many
times, the regulator 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 fl ow rate
Range of inlet pressure
Range of outlet pressure
Range of fl uid temperature
Range of ambient temperature
Pressure readings should be taken at every location that 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.
Below are some of the more common complaints along with possible causes and remedies.
1. Erratic regulation, instability or hunting.
2. Erratic regulation, instability or hunting (liquid service).
b. Pressurize inlet to 30 psig (2.1 Barg) with
air, GN
2
.
c. Tube outlet to a beaker of water to ob serve
number of escaping gas bubbles.
3. Pressure Containment Test.
a. Pressurize inlet and outlet to 1.0 x Upper
Value of Range Spring or 30 psig (2.1
Barg) with air or GN
2
, whichever is higher.
b. Soap solution test all external leak points;
plugged connections, diaphragm fl ange,
di a phragm bolting and spring chamber
vent open ing.
4. Excessive leakage will require disassembly,
examination of sealing elements, correction of
problem, reassembly and retesting. Leakage
path may be via plug/seat or dynamic side
seal.
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 minimum and
maximum fl ow; if necessary, replace with smaller regulator.
Possible Causes Remedies
A. Air trapped under diaphragm.
A. Install valve on external sensing port and bleed off air. (Install regu-
lator upside down to help prevent reoccurrence.)