Cashco BQ User Manual
Page 5
IOM-BQ
5
VII. TROUBLE SHOOTING GUIDE
7. Bench test unit for suitable operation. NOTE:
Reg u la tors are not tight shutoff devices. Even if
pressure falls below setpoint, regulator may or may
not develop bubble tight shutoff. In general, tighter
shutoff can be expected with a composition seat.
8. Soap solution test around body (1) fl ange for leak-
age. Test pressure should be the maximum al lowed
by the range spring at the inlet.
SECTION VII
Possible Causes
Remedies
A.
Oversized regulator; inadequate rangeability.
A1.
A2.
A3.
A4.
A5.
Check actual fl ow conditions, resize regulator for mini-
mum and maximum fl ow.
Tighten fl ange bolting.
Increase fl ow rate.case and washer. Install new thread
Decrease regulator pressure drop; decrease inlet pres-
sure by placing a throttling orifi ce in inlet piping union.
Install next step higher range spring.
Before replacing regulator, contact factory.
B.
Worn piston/cylinder; inadequate guiding.
B1.
Replace trim.
1. Erratic Operation; chattering
2. Regulator inlet (upstream) pressure too high:
Possible Causes
Remedies
A.
Regulator undersized.
A1.
A2.
Confi rm by opening bypass valve together with regulator.
Check actual fl ow conditions, resize regulator; if regulator
has inadequate capacity, replace with larger unit.
B.
Plugged trim.
B.
Remove trim and check for plugged holes in cylinder.
C. Incorrect range spring (screwing out CCW of adjusting
screw does not allow bringing pressure level to a stable
and proper level).
C.
Replace range spring with proper lower range.
D. Too much build (rise).
D1.
D2.
D3.
Review rise (build) expected.
Contact factory.
If -1+6 differential, ensure that pressure reversal has not
permanently deformed the metal diaphragm.
E.
Restricted diaphragm movement.
E.
Ensure no moisture in spring chamber at temperatures
below freeze point. Ensure no dust or debris entering
vent opening. If rainwater or debris can enter, reorient
spring chamber.
Possible Causes
Remedies
A.
Normal-life diaphragm failure.
A.
Replace diaphragm.
B.
Abnormal short-life diaphragm failure.
B1.
B2.
B3.
Can be caused by excessive chattering. See No. 1 to
remedy chatter.
Can be caused by corrosive action. Consider alternate
diaphragm material.
Upstream (inlet) pressure buildup occurring that over-
stresses diaphragms. Relocate regulator or protect with
safety relief valve.
3. Leakage through the spring chamber vent hole.
Possible Causes
Remedies
A.
Plugged spring chamber vent.
A.
Clean vent opening.
B.
Fluid too viscous.
B.
Heat fl uid. Contact factory.
4. Sluggish
operation.