Owner's manual

TW-407 Rev.-
22
Trouble Possible Cause Remedy
Low operating pres-
sure.
a. Safety valve leaking or frozen open.
b. Safety disc ruptured.
c. Piping leaks to atmosphere.
d.-
lator malfunction.
e. Excessive product withdrawal.
f. Pressure building valve closed.
g. Malfunctioning pressure gauge.
h. Excessive frost on pressure building
coils.
a. Thaw out valve or replace if neces-
sary.
b. Replace disc.
c. Leak test and repair piping.
d. Adjust regulators. Replace if nec-
essary.
e. Check for leaks downstream. Re-
duce product use.
f. Open pressure building valve.
g. Replace pressure gauge.
h. Thaw pressure-building coils.
Excessive system
pressure.
a. Extensive shutdown time.
b. Low withdrawal rate.
c. Malfunction of pressure-building cir-
cuit.
d. Malfunction of pressure gauge.
e. Bad vessel vacuum.
a. No remedy.
b. No remedy.
c. Adjust pressure-building regula-
tors. Replace if necessary.
d. Replace gauge.
e. Perform NER test. Have vessel re-
paired and re-evacuated if necessary.
Leaking relief valve. a. Dirt or ice in valve.
b. Damaged valve seat.
a. Thaw out valve. Replace if neces-
sary.
b. Replace valve.
Ruptured pressure
vessel rupture disc.
a. Excessive vessel pressure.
b. Defective rupture disc.
c. 
fatigue.
d. Interior disc corrosion.
e. Relief device failed.
a. Excessive system pressure trouble
section. Replace rupture disc.
b. Replace rupture disc.
c. Replace rupture disc.
d. Blow out safety device line. Re-
place rupture disc.
e. Replace relief device and rupture
disc.
