Ashcroft T7 series Manuale di installazione e manutenzione - Pagina 13
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When the switch is exposed to process media that may harden and/or build up in the pressure port, the switch
should be removed and cleaned as needed.
However, to ensure reliable operation and a long lifetime for the device, we recommend that it is checked regularly.
9.1 Safety
When undertaking servicing work on the device, the pressure lines must be depressurized, the electrical connections
isolated from the mains supply, and the plant secured against being switched on again.
9.2 Check on function, and recalibration
The check on function and recalibration is carried out at regular intervals, depending on the application. The precise
testing cycles should be adjusted in line with the operating conditions and ambient conditions. In the event of various
device components interacting, the operating instructions for all other devices should also be taken into account.
Check on function, in conjunction with downstream components.
Check of pressurized connection pipes for seal condition.
Check of electrical connections.
9.3 Cleaning and maintenance
Never use aggressive solvents.
Do not use high-pressure water to clean the switch.
10 Faults
10.1 Safety
Defective or faulty switches put the operational safety and process safety of the plant at risk, and can lead to a risk or
injury to persons, the environment or the plant.
10.2 Conduct in the event of faults
All defective of faulty devices must be taken out of service. If a repair is required, the device must be sent directly to
our Repairs Department. We request that all returns of devices are agreed with our Service Department.
10.3 Fault table
Possible situations indicating a fault:
Setpoint shift or deadband out of range
Random switch function
Corrosion at process connection and diaphragm
Leakage of process media
Bended stem or bulb
Sharp edged bended capillary line
Damage to housing or wiring
In these instances, replacement of the switch is always required.
10.4 Conduct following fault rectification
See Chapter 8.3 Mounting/Installation
11 Removal, disposal
11.1 Safety
Residues of measuring media in and on removed switches can constitute a risk to people, the environment
and equipment. Adequate precautionary measures must be adopted. If necessary, the devices must be
cleaned thoroughly (see advice in safety data sheets).
11.2 Removal
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