ABB SensyMaster FMT430 Operating Instructions Manual page 137

SensyMaster FMT430, FMT450 THERMAL MASS FLOWMETER | OI/FMT430/450-EN REV. B
1 Sensor
2 Special screws
3 Protection cap
Figure 75: Gaskets on the hot tap fitting
O-ring seals
Pos. Quantity Design
A
2 O-ring Ø 36 × 3 mm (1.42 × 0.12 in), Viton
B
1 O-ring Ø 26 × 3 mm (1.02 × 0.12 in), Viton
1. Disassemble the sensor (see Installation / Disassembly in
connection with the hot tap fitting on page 44).
2. Loosen the fixing screws of the union nut and pull the guide
tube out of the changing device. Clean the guide tube if
necessary.
3. Replace both inside O-rings on the changing device and the
O-ring of the guide tube. Lightly lubricate the O-rings as well
as the threads of the union nut and slip ring of the guide
tube.
4. Insert the guide tube in the changing device and tighten the
fixing screws of the union nut as far as the limit stop in
exactly the same position as during disassembly.
5. Verify correct installation by rotating the lock nut into
measuring and disassembly positions.
6. Install the sensor (see chapter Installation / Disassembly in
connection with the hot tap fitting on page 44).
4 Fixing screws for union nuts (4×)
5 Union nut
6 Flow direction
137