5
MAINTENANCE
WARNING
Disconnect the pump from the EXC300M Controller before you remove the pump from
your vacuum system for maintenance or fault-finding procedures.
5.1
Introduction
The maintenance operations for the EXT250M are described in the following sections. The ISX
inlet-screen, the WCX water-cooler and inlet-flange seals are available as spares (refer to
Section 7). Fit the ISX inlet-screen as described in Section 3.3.1; fit the WCX water-cooler as
described in Section 3.7.1.
5.2
Bearing life
The EXT250M requires no routine maintenance.
The safety bearings will need to be replaced when they reach the end of their service life. This is
typically more than five full speed touchdowns, but may be less; this depends on the type and the
severity of the accidents which have occurred.
The bearings are not user-serviceable. When the bearings need replacement, we recommend that
you exchange your pump for a factory reconditioned replacement. Alternatively, you can send
your pump to a BOC Edwards Service Centre to have the bearings replaced.
When you return an EXT250M pump to a BOC Edwards Service Centre, please use the
procedure included at the end of this manual. However, the instruction to drain all fluids does
not apply.
5.3
Rotor life
The life of the EXT pump rotor is typically 40,000 to 50,000 cycles (of acceleration to full speed,
and then deceleration to a stop). The pump rotor is not user-serviceable.
We therefore recommend that you exchange your pump for a factory reconditioned replacement
every 20,000 cycles, or 10 years of use, whichever occurs first. Alternatively, you can send your
pump to a BOC Edwards Service Centre for a major service (which will include rotor
replacement).
When you return EXT pumps to BOC Edwards Service Centres please obey the procedure
included at the end of this manual. However, the instruction to drain all fluids does not apply to
the lubricant in the EXT pump oil-reservoirs.
26
EXT250M Turbomolecular Pump
