Instruction manual

SM425 INSTRUCTION MANUAL 11.0 INSPECTION and MAINTENANCE
180 42500001 REV A
11.1.3.2
11.1.3.3
11.1.3.4
11.1.3.5
Remove the Terminal Box
1. Open the terminal box and remove the three terminal connections (CELL+, TC+, and TC-).
2. Remove terminal block SCREWs (28) before disconnecting the two HTR wires from the terminal
block. The other terminal connections remain connected.
3. Remove the two SCREWs (15) that fasten the COVER (12) and slide the cover to the flange side.
4. Remove the four Bolts (10) and the terminal box (16) with care so the heater strut assembly wires
will not get caught in the terminal box.
5. For pressure compensation type detectors, remove the SCREW (36) and PLATE (37) on the
ADAPTER (35). Remove the adapter, drawing the wires of the heater strut assembly through it.
Replace Heater Strut assembly
1. Remove CONNECTOR (13) by loosening SCREW (19) until the connector can be removed from
the heater strut assembly. There’s no need to remove retaining O-ring (18).
2. Remove the SCREW (8) at the tip of the probe with a special tool (part no. 9470BX or equivalent)
and then remove the HEATER STRUT ASSY (23) from the detector PROBE (24).
3. Insert the new HEATER STRUT ASSY (23) into the detector PROBE (24), while guiding the
probe calibration pipe through the heater section and into the bracket hole of the heater strut
assembly.
4. Coat SCREW (8) with grease (NEVER-SEEZ: G7067ZA); the replacement screw shipped with
the heater strut assembly is already coated. Fasten the HEATER STRUT ASSY (23) to the
PROBE (24) with SCREW (8) and tighten with special tool (part no. K9470BX or equivalent) to a
torque of 12N.m ±10%.
Install the CONNECTOR
1. Remove remaining O-rings (22) from back of CONNECTOR (13) Install O-rings (22) over the
calibration and reference pipes. Use new O-rings if they are damaged.
2. NOTE: If you attempt to insert the calibration-gas and reference-gas tubes into the connector
without disassembling it, the O-rings may be damaged. Remove SCREW (25), PLATE (17), and
the two CAPs (20) from CONNECTOR (13).
3. On pressure compensation type detectors, install O-ring (14) between connector and probe.
4. Pass the heater and thermocouple lead-wire through the CONNECTOR (13). Insert the
calibration-gas and reference-gas tubes through the holes of the CONNECTOR (13).
5. Install O-rings (21) over the calibration-gas and reference-gas tube ends. Use new O-rings if they
are damaged.
6. Push the two CAPs (20) into the associated opening of the CONNECTOR (13). Insert the PLATE
(17), aligning it with the groove of the CAP (20), and tighten it with the SCREW (25). Tighten the
SCREW (19) until there is no movement between the CONNECTOR (13) and the HEATER
STRUT ASSY (23).
7. For pressure compensation type detectors, insert O-ring (14) between the CONNECTOR (13)
and ADAPTER (35). Pass the heater and thermocouple lead-wires through the holes in the
adapter. Attach the adapter to the connector using PLATE (37) and SCREW (36).
Install the Terminal Box and Wiring
Install in reverse order of the above terminal box removal procedure. If there are no markers on the wiring
from the heater strut assembly, identify the wires as follows; the two wires coming from the ceramic