Cashco DA2 - Positive Differential User Manual
Page 13
IOM-DA2
13
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
conditions.
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.
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.
D. Unstable loading pressure.
D1. Stabilize loading pressure; i.e. pump, control valve, etc.
D2. Air in loading piping. Vent spring chamber.
1. Erratic regulation, instability or hunting.
Possible Causes
Remedies
A. Supply pressure is down (conformation pressure gauge).
A. Increase supply pressure.
B. Undersized regulator.
B. Check actual fl ow conditions; resize regulator for minimum
and maximum fl ow; if necessary, replace with larger
regulator.
3. Downstream pressure will not reach desired setting.
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.)
2. Erratic regulation, instability or hunting (liquid service).