Thermo Scientific 42iQHL, Instruction Manual

Page: 226 / 322

Servicing
Vacuum Pump Diaphragm and Valve Replacement
7-20 42iQHL Instruction Manual Thermo Scientific
Use the following procedures to replace the diaphragm and valve for the
vacuum pumps.
Equipment Required:
Allen wrench, 4 mm
Nut driver, 7/32-inch or 5.5 mm
Allen wrench, 3 mm
Spanner wrench, 3.8 mm diameter by 4.5 mm long inserts
Small flat-blade screwdriver
Large flat-blade screwdriver
Cleaning agent (alcohol)
Fine-grade steel wool
“LOC-TITE” blue breakable thread adhesive
Use the following procedure to replace the diaphragm (Figure 7–5).
1. Undo the four socket head cap screws and washers (“C”) for each head
and lift off the heads with tubing from the pump body. Keep the heads
connected if at all possible: disconnecting and then reconnecting the
PTFE tube can cause leaks.
2. Check for smooth opening and closing of the reed valves (“Q”): a
number of sets of diaphragms can be replaced before there is a need to
replace the valves. Follow the instructions for “valve replacement” if
changing of the valves is required.
3. Use the spanner wrench to loosen and remove the one-piece clamping
disc/screw (“E”). Remove the old diaphragms from both heads (“G”).
4. Remove the four pan head screws with M5 washers (“J”) and remove
the housing cover (“K”) from the front of the pump body. If necessary,
Vacuum Pump
Diaphragm and
Valve
Replacement
Diaphragm
Replacement