Ametek ASR900, Installation And Maintenance Manual

Page: 69 / 92

Maintenance | 4-17
Follow this procedure in the order listed to ensure a complete and proper
job is done while changing out the Heater Assembly’s internal parts.
Before working on the HAG Probe and its Heater Assembly, perform
a manual backpurge on the analyzer to remove any residual gas in the
sample system. Then, close the Double Block valves (optional – if in-
stalled) and then the Sample and Vent line valves on the HAG Probe.
To replace parts in the Heater Assembly (Figure 4-4):
This procedure assumes that all safety precautions have been met to
safely power down the analyzer and HAG Probe and its temperature
zone circuitry and to prepare the analyzer for maintenance, as de-
scribed earlier in this chapter.
This procedure also assumes that the Insulating Jacket has been
removed from the HAG Probe, the Probe Heater Assembly has cooled
down enough to ensure safe handling, and the Heater Assembly has
been disconnected and pulled back from the HAG Probe, as described
earlier in this chapter.
Do not proceed until these conditions have been met.
1. Loosen the set screw on the Junction Box Cover enough to allow the
cover to be removed. Use a suitable tool to turn the threaded cover
counter-clockwise and remove it from the Junction Box Body. Take
care to avoid damaging the o-ring and the threads.
Remove the ground screw and washer from the Junction Box Body
and pull back the ground wire out of the way.
2. Record the tag locations of the field wires on the Terminal Blocks to
use later when installing the new parts. These terminations can also be
found in Figure 4-5.
Loosen the screws securing all of the field wires and the wires that
make up the RTD cable on the Terminal Blocks in the Junction Box.
Remove and pull back the wires from the Terminal Blocks.
!
WARNING
!
WARNING