REMOTE INTELLIGENT SENSOR - AREA MONITOR
entered. These practices, if regularly carried out, will build up an informative system history. This will show trends and prove a useful diagnostic aid should this be required. The time taken to check and record parameters for each cassette change is normally only a few minutes.
4.14 MECHANICAL TIGHTNESS
It is good practice to carry out an annual check of mechanical security. The check should include:
4.14.1CABLE GLANDS. Check that cable glands are tight.
4.14.2DOOR SWITCH. Make sure that the door switch is correctly adjusted. The procedure for checking and adjustment is in Section 4.7.
4.14.3DOOR SEALS. Ensure the door seals are effective. Also check that the door securing screws are in sound condition and not strained to the point that replacement is required. The door seals are reliable and seldom need attention. Door securing screws can be strained by over tightening and it is recommended that spares are carried. The catalog number is shown in Section 5.
4.14.4SAMPLE INLET. It is ESSENTIAL that the input tubes is properly engaged in the block. Otherwise a suitable, undiluted, sample will not be conveyed to the point of measurement.
There is no reason for the tube to become displaced on its own, however the functional importance of this element fully justifies a careful check. Correct assembly of the input tubes is shown in Figures
4.14.5INTERFACE TERMINAL SCREWS. Check the screw in each used terminals for tightness.
4.15 INPUT PATH CLEANING
Occasionally, check for excessive paper dust in the open tape gate. A check every 2 or 3 months is usually adequate. If it is required, blow the tape path and block clean with a hand bellows or can of pressurized air. The use of a factory air line is not recommended unless the air supply is known to be filtered and dry and it is used carefully.
More extensive cleaning is not normally re- quired unless sampling conditions are very dirty, dusty, or otherwise adverse. If additional cleaning proves necessary, see Section 4.10.
4.16 PUMP CHECK
Annually check the sampling pump for excessive current and noise (see Section 4.8). These checks do not require physical pump access but any further examination, or pump replacement, will require removal of the mechanical chassis in which the pump is mounted.
Indicators of excess current and noise, referred to above, may result from wear in motor bearings, or the eccentric. Misalignment or looseness of the motor relative to pump body is another possible cause. If wear is the problem, replace the complete motor/pump assembly. Misalignment, if not accom- panied by wear, can be adjusted. For pump replace- ment catalog numbers see Section 5.
4.17 CHARCOAL FILTER & TUBING CHECK
Annually, or biannually, access the pneumatic module (under the mechanical chassis), change the filter and clean the tubing as necessary.
4.18 TROUBLESHOOTING GENERAL
The following sections assume the reader has appropriate competence and skill. In case of any doubt or difficulty refer to one of our Service Centers for expert assistance.
4.19 EXCESSIVE INPUT CURRENT
Any increase in the input current should be investigated and accounted for. The most likely reasons for high input current are:
4.18.1HIGH CHARGING CURRENT. This may be due to normal recharging after an extended period of power interruption and the system running on battery support. If this is the case the charging current will reduce to normal after a period of some hours. Other reasons for an increase in charging current include a badly adjusted input voltage (see Section 2.8.2.1), and a deteriorating battery.
4.18.2HIGH PUMP CURRENT. The pump running current can be checked as described in Section 4.8. If it has increased significantly it is generally an indication that the pump is worn and needs replacing (Section 4.11).
4.20 LOW PUMP FLOW
If the flow, when checked at cassette change, is found to have reduced significantly, check for the cause. These could be:
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