14
TROUBLESHOOTING
TROUBLE
The pump does not reach “blank-off” pressure
or takes too long to evacuate the system.
Possible cause
: Contaminated oil is the most
common cause of not reaching ultimate pressure.
Remedy
: Shut off the pump, after the operating
temperature has been reached, drain the warm oil
from the pump. Flush and fill the pump with new oil
and take a new “blank off” measurement after oper-
ating temperature is reached (20-30 minutes).
Possible cause
: Solenoid valve not opening
properly or inoperative..
Remedy:
Check and clean valve or replace coil.
Possible cause
: Loose intake flange or head bolts
Remedy
: Tighten bolts
Possible cause
: No oil or not enough oil in the oil
reservoir.
Remedy
: Shut off the pump, add the necessary oil,
or if oil seems contaminated, drain the balance of
the oil from the pump, exchange oil filter and refill
with fresh oil. Flush if necessary.
Possible cause
: Oil line connection leaking
Remedy
: Tighten if necessary
Possible cause
: Exhaust valve not sealing.
Remedy
: Disassemble and clean if necessary.
Possible cause
: Threaded connections leaking
Remedy
: Paint with vacuum sealant
Possible cause
: Shaft seal leaking
Remedy
: Inspect and replace if necessary
Possible cause
: The internal parts are worn or
damaged.
Remedy
: Contact U.S. Vacuum for instructions.
TROUBLE
The pump is excessively noisy
Possible cause
: Typical noise at high vacuum
Remedy
: Open gas ballast valve
Possible cause
: Poor or no oil lubrication
Remedy
: Check solenoid valve/coil, replace if
required. Check oil lines for blockage, clean or
replace.
TROUBLE
The pump will not start
Possible cause
: Motor overloads tripping out
Remedy
: Check overload settings Vs motor
nameplate value. If necessary use 1 size larger
thermal overload
Possible cause
: Possible internal seizure
Remedy
: Disassemble and correct
TROUBLE
The pump will not turn over when motor
starts
Possible cause
: Belts too loose
Remedy
: Tighten V-belts
Before attempting to locate the cause of the of poor ultimate pressure,
check the accuracy of the vacuum gauges on the system.
