Dearator Level

Have all the relevant instruments recently been calibrated?

Even if so, a first step would be to check the calibration.

instruments are not calibrated since 2 months.. what may be the reason of low dearator water level..even make up water pump and dearator level controller are working normally...

DAR ....so are you saying that by opening A valve (which one?) you get a false reading? one would speculate that it is related to the pressure, that it is sensing, at that point. Is there a sight glass attached? suppose you are holding the water under pressure(in this semi sealed tank ) and if you reduce the pressure what will happen? ... perhaps .... Flash Gas, or a condition of bouncy Betty (water level). one important thing to understand with water level controls.... at or near Steaming pressure... doNOT do anything fast, slow and steady works best. I'm assuming that your controls have worked in the past and you are just having difficulty in operating / learning the limits. Regards, Ray

1 -(when we partially open the steam valve to Dearator. dearator level controller works properly. n by opening little more steam valve, it does not work)

steam feeding line for Deaerator are almost permanently opened and automatically controlled according to feed water temperature and feed water source ( fresh or condensate water) . so you need to check and rectify steam feeding control system.Manual opening for steam valve is not recommended.

2 - (there is a huge difference in control room reading and Deaerator level indicator reading.)

Sigh glass level indicator is the more accurate one . only check water valves located at top and bottom of sight glass to assure that they are not stuck up.

then drain water in sight glass and refill again , you will get the accurate water level.

if there is still reading difference , you have to check and calibrate water level electrodes which gives wrong signal for control room.

3 - no pressure builds up inside deaerators tank . it's vented to atmosphere

thanks aish... as u said..drain water in sight glass and refill again, after doing that we get the accurate water level. right.. but i want to know why this problem happens..means what may cause the low level of dearator? perhaps make up water pump is in normal operation and dearator level controller working normally as well. /

(what may cause the low level of dearator?)

According to your explanation ,I think that there is a certain mistake in last calibration process . it may need a qualified person who aware wiring diagram for auto controller and its components .

you may have one of the following mistakes

1- level electrodes might be changed with improper length for the new one .

2- changing wiring connection for electrodes terminal.

3 - changing electrode's location.

4 - disconnected high level electrode (the shorter one)

I hope it may solve your problem

Sounds as though when your last calibration was done, the valve was either closed or only partially open. The person doing the calibration didn't know about the valve state, and just changed the calibration on control room instruments.