Deaerator Water

Much too high of level?

Can you be more specific? What do you mean by "coming with gas vent"? Is gas being vented out of the water or what?

Undercapacity Deaerator.

Was it locally made by the Boiler Supplier? I doubt if you have the technical broucher of it.

Normally they have a one size assuming it fits all sizes of Boiler capacity/feed tanks.very common in India/Pakistan.

Probably oversized vent. Provide vent of smaller hole and check

Good answers already given.

Plus the vent valve may be dirty or corroded or simply not sealing quick enough......

Is there a "Non Return Valve" ?

In the ones I have seen (small domestic ones only), there is a float that is heavy enough to drop and open the valve when only in steam or air, but floats up and seals the valve when immersed in water.....

In the ones I have seen, there was no "Non return" valve, but I am not widely experienced in such things.....I cannot imagine that there is a need for one, but fully prepared to be wrong on that point. No argument!

The ones I had trouble with had got too much calcium carbonate(?) deposits from hard water, to work and seal correctly, or the float had got blocked from hard water deposits.

A good clean with coffee machine descaler fixed my (and several neighbours over the years) problems....

Are you operating at about 5 psi (1/3 bar)? If you are too high it will spurt.

Also, check and see if everything is in its proper place inside. Often there is a baffle or deflector plate that isolates the vent from the spray action of the steam injectors.

What is the flow rate of water and steam. What is the source of steam, what type of extraction (controlled/uncontrolled). When does, the problem that you've mentioned, happens (full load/partial load). I need answers for these before i can come up with some thing.

.We are using 1.3kg/sq-cm pr.of steam from our back pr.turbine.uncontrolled extraction.it happens at full load.

This may be an indication of the baffle failures since the water is not atomised or too high steam pressure into the deaerator.

At full load the steam regulator valve to the DA is likely wide open. If everything is not in place or DA is undersized this will happen.