Superior Boiler Economizers
On-Line Pricing, Performance, and Proposal Generator
Featuring the Specification Assistant

Boiler Make
Boiler Capacity

Inlet Water Temp Deg F
Firing Rate Load Condition 1
100 % Firing
Load Condition 2
% Firing
Load Condition 3
% Firing
Load Condition 4
% Firing
Inlet Flue Gas Temp Load 1 Required
Flue Gas Temp @ 100% Load is Only Required Entry - Part Load Temperatures are Automatically Calculated if Left Blank
Annual Hours @ Firing Rate
Excess Air % % % %
Flue Gas Recirculation Rate % FGR Taken Before Economizer
FGR Taken After Economizer
Unit Selection ECONOMY - Coiled Unit - Ideal to 300 HP
BASE - Base Model
MIDRANGE - Mid-Range Recovery
LARGE - High Recovery Unit
INDUSTRIAL - For Largest Boilers

BYPASS ECONOMY COILED: Disables Bruce from consideration of coiled units

Fuels Fired High-Performance Aluminum Fins - No Price Increase - Overrides Automatic Tube Material Seclection
5 Fins per Inch - Gas Firing With Standby #2 Oil - 316 Stainless Steel Tube
5 Fins per Inch - Gas Firing With Standby #2 Oil - SA-178-A Carbon Steel Tube * SA-178-A tube suitable for deaerated water applications only.

5 Fins per Inch - Gas Firing With Standby #2 Oil
4 Fins per Inch - Gas and/or Consistent #2 Oil Firing
3 Fins per Inch - Heavy Fuel Oil Firing

Current Boiler Efficiency %
Blowdown Rate % - For boiler feedwater applications only
Stack Diameter in Leave 0 if diameter unknown
Fuel Price dollars per million btu
Maximum Water Side Pressure Drop PSI

Optional Selections Below

Custom Water Flow Rate


Check to allow flow rate to track firing rate.

Enter the water flow rate ONLY if the flow rate will differ from the boiler capacity flow rate. This feature is for economizers used in a non-traditional installation such as process water heating. If your application is a typical boiler economizer arrangement then leave this cell blank and leave units on PPH.

Two-Stage Economizers


Check to Select Two-Stage Economizer Unit
Enter Second Stage Water Inlet Temperature
Enter Second Stage Water Flow
Second Stage maximum Water Side Pressure Drop: PSI
Check to allow flow rate to track firing rate.
Click for Split-Titan - Lowest Cost Two-Stage for boilers over 400 HP
Bruce chooses the optimum configuration (recommended)
Force a Stacked Two-Stage
Force a Side-By-Side Two-Stage

Stacked Economizers


Do Not Stack Units
Double-Stack Units
Triple-Stack Units
Stacking economizers is a way of increasing heat recovery by placing two identical units inside of a common casing.

Targeted Flue Gas Exit Temperature


Enter Target Gas Exit Temperature deg F
Stay with Model Selected
Increase Model Size
If you need a unit to meet a specific flue gas exit temperature enter the value in the above data field and Bruce will manipulate various designs to come as close as possible.

Stainless Tube Override


Override ON - All tubing will be stainless steel
Override OFF - Bruce will select optimum tube material

Water Specific Heat


for glycol systems

Specification Assistant

Bruce can assist with selections for projects with industry standard specifications. If you are bidding to one of the specifications below simply click the appropriate spec and Bruce will adapt the proposal to address.
No Specification


Default. Standard HeatSponge supply. No specifications involved.
Veterans Administration Hospital Specification


Standard VA Hospital specifications are riddled with conflicts and mistakes such as the the supply of stainless tubes to Section 1 construction; stainless is not permitted per Section 1 of the ASME Boiler Code. Words in orange require you to conform to the specific spec.

Select Compliance & Clarifications to Standard VA Specification:

  • A. Heat exchangers to transfer heat from boiler flue gases to boiler feedwater.
  • B. Type: Rectangular configuration, replaceable finned tubes, up flow flue gas, parallel flow water, insulated casing with removable panels allowing access to all tubes for cleaning and replacement. Arrange tubes to permit lane type soot blowing.
    Flue gas bypass damper
    Flue gas bypass damper IS NOT required
    Flue gas bypass damper IS required
  • C. Performance: Refer to schedules on drawings. Coordinate input flue gas temperatures with data from boiler manufacturer.
  • D. Construction:
    1. Comply with ASME Boiler and Pressure Vessel Code, Section 1. Design unit to permit operation with no water in the tubes at the temperature listed below.
    2. Design Pressure:
      • a. Water Tubes, 2050 kPa (300 psi) minimum.
      • b. Inner Casings, 2.5 kPa (10 inches water column) minimum.
    3. Design Temperature, 370 C (700 F).
    4. Tubes and Headers: ASTM A254, Type 316 Stainless steel. Helically wound non serrated stainless steel fins continuously welded to tubes. 2050 kPa (300 psi) flanged piping connections. Drainable by gravity. Return bend areas shall be exposed to the bulk temperature of the flue gas. Headers shall be external to the casing. Fin density shall not exceed Maximum fin height, 13 mm (0.5 inches).
    5. Casing: Double wall, removable panels, with insulation between walls. 80 mm (3 inch) angle flanges on flue gas inlet and outlet for attachment of breeching and stack.
      • a. Inner Casing, stainless steel, all welded. Steel angles for breeching attachment to casing. Entire casing systems must be gas tight.
      • b. Insulation: Mineral fiber, ASTM C612, 50 mm (2 inches) thick.
      • c. Outer Casing: Galvanized or painted steel, 0.4 mm (0.016 inches) thick.
  • E. Accessories:
    1. Safety Relief Valve: Valve designed for steam and water service, ASME National Board certified, selected by economizer manufacturer in accordance with ASME Code requirements.
    2. Soot Blowers: Provide sufficient number of blowers to clean all tube areas. Location, arrangement and quantity based on recommendations of soot blower manufacturer for type and size of economizer furnished. Soot blowing shall be lane type.
      Sootblowers ARE NOT specified
      Rotating valve-in-head sootblower IS specified
      Oscillating ring assembly sootblower with timer in remote control panel IS specified
    3. Inlet and Outlet Transitions: Designed and furnished by economizer manufacturer.
    4. Instrument package
      Instrumentation package IS NOT required
      Instrumentation package IS required
    5. Stack corrosion control system: Automatically modulate an internal stack gas damper to control the temperature of stack gases leaving economizer as measured by stack temperature sensor.
      Corrosion control system IS NOT specified
      Corrosion control system IS specified
  • F. Factory Test and Inspections: Inspect the completed economizer assembly in accordance with the ASME Boiler and Pressure Vessel Code, Section I. Certify the inspection and submit four copies of completed ASME Form P 3 for each economizer.
Two Inch Diameter Tube All Welded Economizers


These specifications are rooted in 1950's era design practices and are generally considered to be obsolete for all boilers under 100,000 pph capacity. These relics from a bygone boiler era do not offer the ability to utilize anything other than carbon steel greatly limiting their flexibility and options for applications. The all welded tube and casing design offers no practical ease of repair throughout its life.

Select Compliance & Clarifications to typical Two Inch Tube Wedled Construction specification:

    Boiler Economizer Specification Typical Rectangular Welded Design"

    • The economizer shall be a rectangular box type, completely packaged unit, utilizing extended surface finned tubes.
    • All pressure parts shall conform to Section 1 of the ASME Power Boiler Code.
    • Tubes shall of the welded type, 2 O.D. with a minimum wall thickness of .120.
    • Return bends shall be cold bent or hot forged.
    • Terminal connections shall be RFWN flanged. Headers shall be SA 106 B material, Sch. 80 minimum.
    • The method of tube-to-header attachment shall be welded.
    • All coils shall be completely drainable by gravity.
    • Method of tube supports shall allow for free flow of hot gases around the welds, return bends and manifolds.
    • Sootblowers shall be installed transverse to the tubes.
      Sootblowers ARE NOT specified
      Rotating valve-in-head sootblower IS specified
    • A gas tight inner seal welded 10 Ga. steel shall be insulated and covered with corrugated, galvanized, carbon steel metal lagging.
    • The tube pitch shall be square to ensure ease in cleaning.
    • The fin attachment shall be by high frequency welding process. Tension wrapped, embedded, or brazed finned tubes are not acceptable. 2
    • The fin material shall be carbon steel.
    • All exterior surfaces not galvanized shall be painted with high temperature paint.

Only experienced boiler professionals should adjust the data below.

Manual Unit Selection / Bypass Bruce - For Experienced Boiler Technicians Only:
AutoPick ON
AutoPick OFF - Manual Selection below
Experienced boiler professionals may bypass Bruce's AutoPick software and manually select a maximum gas side pressure drop from the selection chart below. Just because a data page will be printed out means HeatSponge confirms that a manually selected unit will work on a given boiler. Excessive backpressure will seriously impact boiler operation.

This feature is also a very good way to compare the performance of a competitive unit to a HeatSponge. If you are comparing units and the competitive unit has a higher gas side pressure drop than our AutoPick selects use this feature to see how a HeatSponge would compare to the competitive selection. Some competitors will try to sell a smaller unit with an excessively high backpressure simply to offer a lower price.
Select Maximum Allowable Backpressure:

Flue Gas Mass Flow Calculation Override - For Experienced Boiler Technicians Only:
Experienced boiler professionals may custom select the flue gas mass or volumetric flow rate. You must both enter the flow rate and units to use as well as check the override checkbox.
Bypass checkbox required

Final unit selection could be affected by other operational constraints. Superior reviews all selections for accuracy prior to placement of any purchase order.