Replacing Pwa - Honeywell ST 3000 User Manual

9.4

Replacing PWA

About the PWA
Electronics Board
Procedure
6/05 ST 3000 Release 300 and SFC Model STS103 User's Manual
The circuitry in the ST 3000 Release 300 transmitters is of the single
PWA design. The PWA contains connectors for the flex-tape conductor
from the sensor, the loop power wires and a connector for the optional
smart meter cable.
The procedure in Table 55 outlines the steps for replacing the PWA.
Table 55 Replacing PWA.
Step
1 Turn OFF transmitter power.
ATTENTION We recommend that you remove the transmitter
from service and move it to a clean area before taking it apart.
Loosen end cap lock and unscrew end cap from electronics side of
2
transmitter housing.
We recommend that you use a ground strap or ionizer when handling
the PWA, since electrostatic discharges can damage certain circuit
components.
•
3
If equipped with a Local Smart Meter, carefully turn Smart Meter
counterclockwise to remove it from PWA mounting bracket and
unplug cable from connector on back of meter assembly.
•
Loosen two retaining screws and carefully pull mounting bracket
and PWA from housing.
•
Using the retaining clip, unplug flex tape connector and 2-wire
power connector from PWA, and remove PWA.
Transmitter
End Caps
Local Smart
Meter
Action
PWA and
Flex-Tape Connector
Mounting Bracket
Meter
Cable
Power
Connector
Continued on next page
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