Support

Water system

WATER LEVEL LOW light remains on even after the pump starts.

Check that valves on water supply line are open & there is sufficient water in the tank. Check strainer on water suction side. Clean if found choked. Close the main steam valve, open auxiliary steam valve. Put the FILL switch on and see if water is coming out. Close the auxiliary valve slowly till pressure builds up above 6 kg/cm². If water flow reduces sharply, it indicates problem inside pump. If water flow is less even without pressure, the problem may be with the pump or the suction line. (Accurate measurement of water flow is preferable, but the flow may also be estimated visually.)Remove piping near pump suction. If water does not come out freely, choking of piping of optimizer/economizer is indicated. If the problem is not with suction piping, check the pump.

STEAM TEMP HIGH alarm with boiler trip.

Check setting of steam temperature controller. (2000C for the 10.5 kg/cm2,2100 C for 15 kg/cm² pressure). Check fuel pressure. Fuel consumption may change with fuel properties also, hence ensure that consumption is correct. Observe the steam by opening the auxiliary valve. Spray of wet steam should be visible. Superheated steam is practically invisible. If steam is indeed superheated & fuel consumption is also correct then carry out all the steps explained in (1) to ensure that water flow is not less than normal.

Water Characteristics
For pressures up to 25 bar :-
Total Hardness in Feed water Mg/lit. in terms of CaCO3 max. 2
Feed Water Pump
PH value 8.5 to 9.5
Oxygen Not Detectable
Total solids, alkalinity and silica Not Detectable
Organic matter Not Detectable
Boiler Water
Total hardness, mg/lit In terms of CaCO3 max. ND
Sodium phosphate,mg/lit Na3PO 50-100

Caustic alkalinity, mg/lit In terms of CaCO3 min.

350

Sodium sulphite mg/lit As Na2SO3 or

30-70
Hydrazine,mg/lit as N2H4 0.1-1
Suspended solids,mg/lit max 50
Dissolved solids,mg/lit max. 3500
Numerical Values Depend Upon Circumstances

Total alkalinity, mg/lit In terms of CaCO3max.

1200
Silica, mg/lit as SiO2 max. 0.4 of caustic alkalinity