Fluke Calibration P3031, Руководство пользователя

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6-1
Chapter 6
Fault Finding
Poor PCU Spin/Sensitivity
General
If the piston is not free, do not rotate, as damage may occur — dismantle and clean the
assembly as described in Chapter 5, PCU Assembly.
To check the freedom of the PCU, open the Exhaust valve and hold the weight carrier.
Lift the piston vertically, gently up and down. It should slide freely within the cylinder, if
any resistance is detected, it must be cleaned immediately.
If the spin/sensitivity of a recently cleaned PCU deteriorates quickly, then it is likely that
the lubricating fluid within the PCU housing has become contaminated. This must be
drained out, and the PCU housing thoroughly cleaned and re-primed with clean fluid
before further calibration is carried out.
System Will Not Pressurize
1. Ensure that Inlet and Exhaust valves are closed
2. Ensure for missing or dirty seal in test port.
3. Ensure that the sealing face of the DUT is not dented or scratched, and is correctly
contacting the seal in the test port.
4. Ensure that the external supply is correctly connected and functioning correctly.
5. Ensure that the DUT is not leaking.
6. Check for correct fluid level in the PCU housing.
High Piston Fall-Rate
The piston will always fall slowly due to the small leak between piston and cylinder. This
fall rate will never be so fast that a stable reading cannot be made. If the fall rate is large:
1.
Perform all checks in the System Will Not Pressurize section.
2. If the fluid has recently been topped-up, or the PCU has been removed, trapped air
may be bleeding past the piston. Continue to pressurize and the fall-rate will stabilize
when the trapped air has bled away.