Hello!
Background information
I am a novice "stationary operating engineer/power engineer" depending on where you live. Our steam chart reader we use is the eurytherm 392 since I've been at this facility I've noticed this chart reader has never seemed to be accurate on recording steam flow/flue gas. I've tried blowing down this Anderson greenwood instrument manifold which seems to run to the steam chart. There's two copper lines I open both ball valves simultaneously slowly and there's a ton of condensate that comes out and eventually steam comes out. When I do this steam chart reads 0 KLBS and than returns to reading normal this usually fixes the other steam chart reader on the other boiler. Since blowing down the steam chart reader didn't work I've taken a step further for better or worse and have attempted to calibrate the pens. It seems like the blue pen which is steam flow is stuck in the reading the same flow and the red pen is positioned too low after doing the calibration. I did not manually move any of pens just let the calibration key do its thing for both pens. Can anyone possibly lead me in the right direction on how to fix thank you! Also sorry if this post is formatted poorly first post on this forum.


Pens position when not in use

Pens position when in use

 

Happy New Year !

1. Impulse tubing condensate leg.

The manifold doesn't "go to the recorder", it connects to a differential pressure transmitter that senses the high and low pressures across a primary flow element and reports either the differential pressure, (DP) or the square-root extracted flow rate over a 0-100% range via 4-20ma or a voltage signal output.

Typically on steam, the impulse tubes from the primary flow element to the 3 valve manifold/transmitter are supposed to fill up and remain filled with condensate (water) in order to isolate the transmitter sensing electronics from the heat of the steam. A well designed loop will have provision for re-filling the impulse tubes with water before applying steam to impulse tubing that has been drained. Direct steam heat on the sensor elements can kill the transmitter electronics.

2. Calibrations
The recorder has an "input calibration" function that calibrates the electrical analog input using a known good, signal source, typically a traceable calibrator.

There is a separate "chart calibration" function that adjusts each channel pen so that the pen tracce is at the correct position with respect to the chart's zero and span locations.

3. Possible problems

a. The transmitter is malfunctioning so there's not a good input signal to the recorder analog input
b. scale/dirt/crud has clogged the 3 valve manifold so it's not functioning properly and not allowing the DP transmitter to 'see' the correct steam pressures
c. the recorder analog input is malfunctioning or is way out of calibration. That recorder has a means of restoring factory calibration constants, that can be used to get the channel close to where it should be. A signal source or calibrator can be used to drive the input directly and the chart pen should follow, proving the operation of that channel.
d. the chart calibration is way off
e. The mechanical mechanisms that drive the pen arm are malfunctioning, which a "chart calibration" exercise should reveal.
f. Somebody messed with the configuration so that the recorder is not correctly configured to show the flow rate or flue gas whatever (units?) so you're seeing whatever the incorrect configuration is configured for.

392 Circular chart recorder, Installation and Operation Manual:
https://www.eurotherm.com/?wpdmdl=28222

100mm CONTINUOUS TRACE CIRCULAR CHART RECORDER INSTALLATION AND OPERATION MANUAL:
https://www.eurotherm.com/?wpdmdl=28223