User Guide
Landcal Blackbody Source
Type P1600B2
Page 23
Inserting the new insulation cassette
1) Lift the new insulation cassette into the case and slide it to the front. Refit
the retainer at the rear of the body.
2) Reconnect the element supply wiring to the terminal blocks on the rear of
the new insulation cassette in the positions noted previously.
3) Slide the control thermocouples into position and reconnect them in the
sequence noted previously.
4) Insert the cavity into the furnace by locating the narrowest part of the
cavity (rear) into the brick ‘U’ shape support in the back of the furnace.
Full details are given in section 5.2 of the operating instructions.
5) Carefully fit the elements into the new insulation cassette, ensuring that
the elements are correctly located in the front support holes. To avoid
overheating of the element braid connection, each element is supplied
fitted with 2 off insulation rings at the cold ends of the elements. This ring
should fit closely to the rear of the insulation cassette.
6) Reconnect the element braids in the positions previously noted. The split
line in the cold end of the element must be positioned vertically. Take
care to ensure that the braids do not touch each other or any part of the
insulation cassette. Ensure that the braids will be clear of the back panel
when fitted.
7) Replace the front plug / sighting tube.
8) Replace the front disc.
9) Replace the rear panels, reconnecting the earth tag to the inner panel.
10) Insert the measuring thermocouple sheath until it stops in the groove on
top of the target. To be sure that it is in the recess, gently push up on the
end of the sheath, lift the alignment tab and tighten the 2 screws.
9.6 Replacing the Control Thermocouple
1) Remove the rear panel from the furnace, as described in Section 9.5.1.
2) Disconnect the thermocouple from its terminal block. This may be easier
if the terminal block is first unscrewed from the furnace body. Note if the
terminal block is held away from the furnace body by porcelain spacers.
3) Release the screw which secures the thermocouple sheath.
4) Withdraw the sheath and shake out any fragments of broken thermocouple.
5) Replace any porcelain spacers which were removed from behind the
terminal block.
6) Connect the negative side of the thermocouple to the blue (or blue striped)
wire of the compensating cable. (Some furnaces may be fitted with an
earlier type of compensating cable. In this case the positive side of the
thermocouple must be connected to the red wire).
9.7 Replacing Current Fuses
To access the internal fuses, remove the back panel.
