WIKA TCA - Manual (Page 5)

INSTRUCTION MANUAL
NI-491E
Rev. 5 11/02
11 - STOPPING AND DISMOUNTING
Before proceeding with these operations ensure that the plant or
machines have been put into the conditions foreseen to allow
these operations.
With reference to figures 6 and 7
Remove the power supply (signal) from the electrical line.
Loosen and remove the seal press being careful not to bend the
capillary and protective sheath (Fig. 5).
Loosen and remove the fitting then extract the bulb from the
thermowell holding it by the capillary tube, without bending it.
Unscrew the three piece joint (8).
CAUTION: do not open the cover of explosionproof temperature
switches (Series TCA) when energized, in explosive atmos-
pheres.
Unscrew the three piece joint (10) (electrical cable tubing).
Remove the instrument cover and disconnect the electrical ca-
bles from the terminal block and earth screws.
Remove the screws fixing the case to the panel (or pipe) and
remove the instrument, taking care to slide the electrical conduc-
tors out from the case.
Mount instrument cover. Insulate and protect cables around, if
any. Temporarily plug the thermowell. In case of explosionproof
instruments (Series TCA) it is recommended to follow - at least –
the standard EN-60079-17 for the withdrawal from service of
electrical apparatus.
12 - DEMOLITION
The instruments are mainly made of stainless steel and alumin-
ium and therefore, once the electrical parts have been dis-
mounted and the parts coming into contact with fluids which could
be harmful to people or the environment have been properly dealt
with, they can be scrapped.
13 - INSTALLATION NOTE
13.1 TEMPERATURE SWITCHES CLASS SAMA II A
Difference in height of more than two meters between bulb and
instrument enclosure causes a systematic error of set point cali-
brated value (“bulb elevation error”).
This error can be corrected during calibration by either increasing
or decreasing the set point value by a constant depending on the
difference in height foreseen for the installation. The “bulb eleva-
tion error” can be corrected using the table attached to our tech-
nical instruction IS-TC.401E, available on request.
13.2 TEMPERATURE SWITCHES CLASS SAMA II C
Difference in height between bulb and instrument enclosure when
installed must not exceed two meters.
With a difference of approximately two meters the set point value
fixed during calibration may be affected by an error depending on
the normal reference temperature, the working temperature and
the set point temperature. In the worst operating conditions the
set point temperature value fixed during calibration may be af-
fected by a maximum error of 1.5°C. For further clarification
request IS-TC.401E.