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Turning in lowers indicated reading. 5. Check adjustment by allowing temperature to stabilize and comparing readings. Repeat above steps if necessary. 6. Replace instrument cover and knob. Adjusting Single Switch Types (BCT-800 and 820E) 1. Remove knob and instrument cover, 2. Move the adjustment pointer up scale beyond the indicating pointer. This permits checking the set point by moving the lever arm upward with a finger or tool simulating thermal assembly movement. 3. Connect test lights to indicate switch operation or listen for the switch “click". 4. Loosen adjustment “A” (Figure 17) until the adjustment pointer agrees with the indicating pointer (when the switch “clicks”). 5. Replace instrument cover and knob. NOTE: Indicating pointer deflection — The indicating pointer will read slightly low at bulb temperatures above the controller setting. This deflection is normal and repeatable (approximately .5% of scale range for single switch models) and is due to the transference of the switching mechanism load to the thermal system. It can be measured by moving the setting pointer from the high to the low end of the scale and observing the resultant indicating pointer deflection. NOTE: DUAL SWITCH VERSION IS SHOWN. IN SINGLE SWITCH VERSION, ONLY ONE SNAP-ACTING SWITCH IS USED. SCALE ■ INDICATING POINTER- ADJUSTMENT KNOB SHAFT- SCALE MOUNTING-SCREWS (3) WIRE CLAMP ■ IGTY-2) SWITCH BANK ASSEMBLY EXTENSION SPRING THERMAL ASSEMBLY MOUNTING SCREWS (QTY-2) CAPILLARY ■ ADJUSTMENT "B" 'A HEX (DUAL SWITCH MODELS ONLY) SWITCH MOUNTING SCREW ADJUSTMENT POINTER ADJUSTMENT POINTER MOUNTING SCREW - ADJUSTMENT ''A” ■ PIVOT BRACKET LEVEH ARM ZERO ADJUSTMENT C - HEX -COMPENSATOR WRENCH FLATS ■ INDEX (SEE VIEW B B] ■ THERMAL ASSEMBLY HOUSING CALIBRATIONS INDEX GENERAL LAYOUT (LEADWIRES OMITTED FOR CLARITY) VIEW B B Figure 17 6 CALIBRATION (continued) Adjusting Dual Switch Type BCT-802 1. Connect test lights to indicate switch operation or listen for the individual switch “clicks”. 2. The separation between switches is the difference between the high and low set points. The set points are determined by setting individual adjustment pointers and may be separated up to 100% of the scale range apart. 3. To align either switch to the adjustment pointer the corresponding adjustment “A” must be loosened and set the adjustment pointer to the indicator pointer. NOTE: Switch #1 cannot be set to operate at a higher setting than switch 81 Adjusting Dual Switch Explosion-Proof Type BCT-822E 1. Remove the explosion-proof die-cast cover to permit access to the switches. 2. Move the adjustment pointer up scale beyond the desired difference between the switch settings. This permits checking the settings by moving the actuating lever upward with a finger or tool simulating thermal assembly movement. 3. Connect test lights to indicate switch operation or listen for the individual switch “clicks”. 4. The set point of switch ffl is determihea by the red adjustment pointer. The set point of switch #2*may be adjusted by up to 50% of the range span below the switch #1 set point by turning adjustment “D” in (right hand thread). See Figure 18. The set point of switch tfl should not be above that of switch K\. 5. To align switch #1 to the adjustment pointer, loosen adjustment “A" and set the adjustment pointer to the scale. Correction for Capillary Immersion If the length of capillary immersed in the process differs from the amount immersed in the factory calibration bath, a calibration shift will occur. The error may be corrected as follows: 1. Move set pointer to highest temperature setting. 2. Note indicating scale reading with the head and sensor at room temperature. 3. Loosen the two thermal assembly mounting screws. 4. Reposition the housing index against the calibration on the instrument case (or skeleton casting) at a rate of 1 division line per capillary length listed in table. Move to the left if capillary is to be added to the process, or to the right if capillary is removed from the process. 5. Tighten the two thermal assembly mounting screws. 6. Note change in indicated scale reading (if any). 7. Turn zero adjustment “C" to bring indicating pointer reading back to the original reading noted in RE-ZEROING. Turning in lowers indicated reading. NOTE: Thermal assembly can be returned to its original position by aligning its flange with the line scribed on the instrument case. Model No. Range Capillary Length/Division^ 4 -40 to 1 20 ÛF 4 Ft. 6 0 to 250°F 2 Yi Ft. 7 0 lo 400°F 2 Ft 8 50 to 650°F 2 Ft. 9 50 to 1000°F 2Vt Ft. OPERATION CAUTION: Do not exceed maximum temperature indicated oil the scale as physical damage to the control mechanism may result. PRE-START-UP The control should be checked against a test thermometer of known accuracy before being put into service. As with any precision instrument, minor adjustments may be necessary after shipment and installation. See Calibra...

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