Sizing Deaerator (2-Chamber Atmospheric)

Step 1 : Pump Flow Rate Sizing (Boiler Feed)
Enter Load of Boilers expressed as any of the following units in the drop-down list.	On/Off running pumps	Continuously running pumps
Boiler HP Sq. Feet EDR Lbs./Hour BTUs/Hour MBH Kilowatts (kW)	pump GPM	pump GPM
#1	#2
One or both of the results is LESS than 0.5 pump GPM. We advise you contact your Shipco representative. One or both of the results is GREATER than 500 pump GPM. We advise you contact your Shipco representative.
Step 2 : Pump Flow Rate Sizing (Transfer)
Enter Load of Total System expressed as any of the following units in the drop-down list.	For Continuously running pumps
Boiler HP Sq. Feet EDR Lbs./Hour BTUs/Hour MBH Kilowatts (kW)	pump GPM
	#3
Step 3 : Two Compartment Deaerator Receiver Sizing
Calculated automatically from results in Step 2.	net gallons
	#9
Step 4 : Pump Discharge Pressure Sizing (Boiler Feed)
Discharge Pressure of pumps based on the larger amount. This amount is either the Safety Relief Valve setting on boiler + 3% OR Boiler Operating Pressure + Valve Pressure Drops + Safety Margin.
1. Enter Vertical Lift.	Pumps running On/Off
feet of head	pump discharge psig
#4	#2, #7, #10
2. Enter Boiler Operating Pressure.	Pumps running Continuously (with stack economizer)
psi	pump discharge psig
	#5, #6, #7, #8, #10
3. Enter Safety Relief Valve Setting on Boiler. (optional)	Pumps running Continuously (no stack economizer)
psi	pump discharge psig
#11	#5, #7, #8, #10
Step 5 : Pump Discharge Pressure Sizing (Transfer)
Calculated automatically as "25".	For Continuously running pumps
	pump discharge psig
Step 6 : Stand Height
On all deaerators, the available NPSH is 0 ft. of head unless the deaerator tank is elevated above the pumps. To calculate elevation of stand, determine required NPSH of both the boiler feed and transfer pumps from each pump curve. Take the maximum value obtained of the two pumps and add 2 ft. of head as a safety factor. The result is the MINIMUM required stand height.
Press "Reset All" to CLEAR ALL calculations and enter new values.

Notes

1. Each boiler feed pump on a deaerator is sized based on the total load of boilers fed by the specific pump.
2. For boiler feed pumps running ON/OFF, the pumps are controlled by a boiler level controller.
3. Each transfer pump on surge chamber is sized based on total load of deaerator plus additional water to feed vent condensor that is included on atmospheric design.
4. If boiler and deaerator are on the same floor, enter a value of "0" for feet of head. If boiler is located on a floor above the deaerator, enter vertical height (in feet) from the pump discharge on the deaerator up to the inlet piping on the boiler.
5. Assumes pressure drop through modulating valve of 10 psig or less.
6. Assumes pressure drop through stack economizer of 20 psig or less.
7. Assumes proper discharge pipe size of a velocity of 10 ft/sec or less.
8. Pump discharge pressure must be able to overcome the relief valve setting of the boiler. Relief valve setting on the boiler should be adjusted or replaced so the setting of the relief valve is close to the actual operating pressure of the boiler.
9. The receiver size on 2-chamber deaerators is typically based on the total system load (i.e. sum of all boilers fed by deaerator) with 20 minutes NET storage—10 minutes for deaerator chamber and 10 minutes for surge chamber.
10. Pump discharge pressure MUST BE ABLE to overcome the boiler safety relief valve setting plus three percent of valve setting AND meet all state and local codes.
11. If the pressure differential between the boiler operating pressure and the setting of the safety relief valve on the boiler is greater than 20 psig, consider replacing the safety valve with one rated closer to the boiler operating pressure. Otherwise the motor horsepower of the boiler feed pumps will need to be oversized to provide a discharge pressure sufficient to overcome the rating of the safety relief valve on the boiler. The higher motor HP typically would require a more expensive pump and increases ongoing operating costs.

Shipco® MathWizard™ • Go to Top