NOTICE
Impairment from contamination and damage
Touching the devices or components with bare hands increases the desorption rate and leads to in-
correct measurements. Dirt (e.g. dust, fingerprints, etc.) and damage impair the function.
► When working on high or ultra high vacuum systems, always wear clean, lint-free and powder-
free laboratory gloves.
► Only use clean tools.
► Make sure that the connection flanges are free of grease.
► Remove protective caps and protective covers from flanges and connections only when necessa-
ry.
► Carry out all work in a well lit area.
NOTICE
Electric flashover from helium
Helium can cause electric flashovers in the unit’s electronics which will destroy the electronics.
► Switch off the unit before carrying out a leak test.
► Remove the electronic unit before carrying out a leak test.
Required tools
● Allen key,
WAF 1.5
● Allen key,
WAF 3
● Open-end wrench,
WAF 7
● Pincers for circlip
● Mounting tool for the ignition aid
● Tweezers
Spare parts required
● Repair kit BN 846 238 -T
Required consumables
● Dry nitrogen for blowing out
1
2
3
Fig. 14:
Mounting tool for the ignition aid
1 Anode
3
Mounting tool
2 Ignition aid
Replacing the ignition aid
1. Insert the new ignition aid in the mounting tool.
2. Carefully push the anode (either new or cleaned) into the ignition aid, in the center, and parallel to
the tool axis.
3. Insert the anode approx. 15 mm.
You can find the individual parts here:
(see chapter “Disassembling gauge”, page 31)
Gauge assembling
1. Ensure that sealing surfaces, seals and the ceramic (anode) are clean.
2. Insert the FPM seal (anode bushing) with the inner ring so that it is centric in the measurement
chamber.
3. Carefully insert the anode together with the ignition aid into the measurement chamber.
4. Fit the FPM seal onto the Pirani measuring element in the groove provided.
5. Then insert the Pirani measuring element with the fitted FPM seal into the borehole provided.
Maintenance
34/50
