Installation Of Temperature Sensors - nVent Raychem NGC-20-C-E Installations-, Betriebs- Und Wartungsanleitung

2.3.2 Installation of temperature sensors

The temperature sensors must be installed in such a way that the sensor(s) measure(s) the surface temperature as reliable as possible.
Therefore the guidelines as described in section 2.3.2.1 need to be followed.
2.3.2.1 Temperature sensor of the temperature controller
Important guidelines on sensor positioning and installation:
• The correct position is on top of the pipe. (Figure 2)
• The sensor needs to be attached with sufficient glass tape (GT-66 or GS-54).
• Use two bands of glass tape to ensure its position. (Figure 1)
• The lead wire need to leave the insulation so that no moisture can enter the cladding-insulation system. (Figure 2)
• Fix the sensor lead wire to prevent accidental strain on the sensor tip, which could alter its position.
WARNING:
• Do not install sensor at ambient temperatures below –20°C. Do not bend sensor (last 50 mm), keep it straight under all
circumstances. Minimum bending radius for extension cable: 5 mm.
• No metal straps may be used for fastening, because they could damage the sensor when tightened. For this reason the use of fibre-
glass self-sticking tapes is recommended.
Figure 5: Mounting temperature sensing on pipe
Sensor
Pipe
No
Lead entrace
Figure 6: Sensor and lead entrance
2.3.2.2 Installation of the temperature sensor of the safety temperature Limiter
The NGC-20-CL-E knows two methods of limiting the surface temperature of the heating cable.
2.3.2.2.1 On the pipe surface
The first method consists of using the surface temperature of the pipe as reference and preventing powering the heating cable when the
pipe temperature is above a calculated value. This value is depended on the make of the cable and the design of the heating circuit. Use
TraceCalc Pro to determine this value and document the calculation in your filing.
The sensor is installed identical to the normal temperature sensor, at the top of the pipe, firmly attached to the surface by means of
glass tape. Special attention needs to be taken that the sensor lead does not cool the pipe/sensor; nor that moisture could enter the
insulation, cooling the sensor tip or reducing the insulation capacity in this area.
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