Edwards APGX-H, Instruction Manual, Page: 22 / 32

D023-92-880 Issue F
Page 16 © Edwards Limited 2018. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Maintenance
If the APGX-H is connected to an Edwards AGC, TIC or AGD, the display will indicate the corresponding pressure.
5.1.4 Reset factory calibration values
Note: Performing a factory values reset will overwrite any existing calibration data stored in the tube.
The use of factory calibration reset will not correct a filament that has drifted with time or due to
contamination.
Perform the following procedure in order to restore the calibration values when the gauge was initially
manufactured:
1. Disconnect the power supply to the gauge.
2. With the power disconnected, press and hold the ' CAL ' switch.
3. Switch on the power to the gauge with the '
CAL
' switch still depressed and hold the switch down until the status
LED flashes red. This takes approximately six seconds. The factory calibration values will now be restored.
5.2 Clean the filter
CAUTION
You must remove the filter to clean it. Do not clean the filter in position in the body tube as permanent damage
to the filament can occur.
Refer to Figure 1 and use the following procedure to clean the filter. The filter can only be replaced on NW flange
versions of the gauge.
1. Switch off the electrical supply, ensure that the vacuum system is at atmospheric pressure and remove the
APGX-H from the vacuum system.
2. Use circlip pliers to remove the filter-retaining circlip (3); ensure that you do not damage sealing surface on the
flange or the inside of the body tube. Remove the filter (5).
3. Inspect the filter. If the filter is damaged or cannot be cleaned, replace the filter; a filter replacement kit is
available as a spare (refer to Section 7 ).
4. Use a suitable cleaning solution to degrease the filter, then wash the filter repeatedly in clean water.
5. Wash the filter with a suitable solvent to remove all traces of water and then thoroughly dry the filter.
6. Refit the filter into the body tube and refit the circlip.
5.3 Replacing the tube
Loosen the two screws and detach the tube from the electronics housing. Plug the replacement tube into the podule
and secure the tube retaining screws (item 1 in
Figure 6 ). To ensure a good electrical connection between the tube
and electronics housing, the securing screws should be tightened. The new tube contains calibration information
preset in the factory however for optimum performance and accuracy it is recommended that the vacuum and
atmosphere adjustment described in
Section 5.1 is carried out before use.