
BT- 434 Rev.A
23
Trouble-Remedy Guide
MAINTENANCE
Trouble
Possible Cause
Remedy
1. Low operating pressure.
a. Safety valve leaking or frozen
open.
a. Thaw out valve or replace if
necessary.
b. Safety disc ruptured.
b. Replace disc.
c. Piping leaks to atmosphere.
c. Leak test and repair piping.
d.
Pressure building / economizer
regulator malfunction.
d. Adjust regulators. Replace if
necessary.
e. Excessive product withdrawal. e. Check for leaks downstream.
Reduce product use.
f. Pressure building valve closed. f. Open pressure building valve.
g. Malfunctioning pressure
gauge.
g. Replace pressure gauge.
h. Excessive frost on pressure-
building coils.
h. Thaw pressure building coils.
2. Excessive system pressure.
a. Extensive shutdown time.
a. No remedy.
b. Low withdrawal rate.
b. No remedy.
c. Malfunction of pressure build-
ing circuit.
c. Adjust pressure building regu-
lators. Replace if necessary.
d. Malfunction of pressure gauge. d. Replace gauge.
e. Bad vessel vacuum.
e. Perform NER test. Have vessel
repaired and re-evacuated if
necessary.
3. Leaking relief valve.
a.
Dirt or ice in valve.
a. Thaw out valve. Replace if nec-
essary.
b.
Damaged valve seat.
b. Replace valve.
4. Ruptured pressure vessel rup-
ture disc.
a. Excessive vessel pressure.
a. Refer to Step 2, this section.
Replace rupture disc.
b.
Defective rupture disc.
b. Replace rupture disc.
c.
Atmosphere corrosion and/or
disc fatigue.
c. Replace rupture disc.
d. Interior disc corrosion.
d. Blow out safety device line. Re-
place rupture disc.
e. Relief device failed.
e. Replace relief device and rup-
ture disc.