Automatic blowback option (/av) – Yokogawa Single Channel Oxygen Analyzer System ZR22/ZR402 User Manual

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IM 11M12A01-01E-A

7. Automatic Blowback Option (/AV)


Principle of Operation

This option should be chosen when there is a probability of process particles clogging the sampling
system. The design consists of an automatic blowback valve and solenoid that is activated by the
ZR402G Single Channel Oxygen Analyzer or the AV550G Multi-Channel Oxygen Averaging Unit.

The actuator uses a 4-way, 2 position single solenoid valve with a double acting air actuator.
The automated valve closes when blowback is initiated, thereby isolating the detector during
blowback operations. The actuator is electrically controlled by a solenoid, which is pre-wired
from the factory.

NOTE: This option requires a ZR22P-S split design flange.
NOTE: The /AV option is NOT suitable for Hazardous Area Classification.


Piping to the split adapter

7.2.1 Block Valve with Actuator

The actuator requires 80 psi (60psi minimum) of clean dry instrument air. Attach ¼” stainless
steel tubing to the ¼” FNPT fitting of the blowback solenoid. The tubing between the solenoid
and actuator is prefabricated at the factory. The block valve is controlled by a single solenoid,
where the valve closes when the solenoid is energized and opens when deenergized


7.2.2 Blowback Air

The blowback air solenoid uses between 60 psi and 80 psi of clean dry instrument air. Attach
¼” stainless steel tubing to the ¼” FNPT fitting of the blowback solenoid, which is mounted at
the ZR22P adapter.


Wiring to the ZR402G for blowback

NOTE: Run separate conduit for heater and signal wiring.
NOTE: For additional information regarding set up procedures for the ZR40G and blowback
sequence refer to the ZR402G Instruction Manual IM11M12A01-02E, Chap10.2

Heater output: 14AWG, 1 twisted pair (2 conductor) with shield terminated at the converter

Signal output: 16 AWG, 3 twisted pair (6 conductors) with the shield terminated at the converter.

Less that 10 ohms total loop resistance


For additional wiring details, refer to the wiring diagrams in Appendix .

7.3.1 Adapter Tee Blowback Control

The user provides power supply input to the ZR22P. The Cable should meet all NEC codes for 115
VAC, 10A supply. The user also provides a 14 AWG, 2 conductor cable from the ZR402G to the