Ametek ASR900, Installation And Maintenance Manual

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4-20 | Heated Acid Gas Sample Probe (Large Diameter)
7. Remove the o-ring using an o-ring removal tool to avoid damaging
the groove or the Heater Block joining surface.
Every time the Heater Assembly cover is removed, the internal o-ring
must also be replaced.
DO NOT INSTALL THE NEW O-RING AT
THIS TIME. Instructions on when to install the o-ring are described
later in this procedure.
Continue with Step 8 (Over-Temperature Switch), Step 9 (Heater
Cartridge), and/or Step 10 (RTD) as necessary for the removal and
replacement of these parts.
If replacing only one of these items, follow only the procedure for the
appropriate step. If you are replacing two or more items, follow the
procedure for each of the steps.
Some steps for the different part
replacement procedures may be the same and certain procedures,
such as routing wires, can be done at the same time.
8. Replace the Over-Temperature Switch:
a. Loosen and remove the (2) M3 x 6 screws and (2) 3 mm Internal
Toothlock Washers that secure the Over-Temperature Switch and
its mounting bracket in place.
b. Using a soldering iron, remove the solder from the wires on the
Over-Temperature Switch and remove the two wires.
Remove any excess solder from the bottom of the Heater Block.
c. Assemble the new Over-Temperature Switch (P/N 300-8637) and
install it in the Heater Block.
Do not fully tighten the (2) M3 x 6 screws that are used to secure the
Over-Temperature Switch at this time. The Over-Temperature Switch
and Heater Cartridge wires must be soldered before securing the
Over-Temperature Switch in place.
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