HeatSpongeby Boilerroom Equipment, Inc.

Bruce / Rainmaker proposal generator

Keep the boiler.
Recover more heat.

Compare a Rainmaker retrofit with a condensing boiler at your actual water temperatures, or select a unit for a specific exhaust-temperature target.

Start selection Explore Rainmaker
Rainmaker external economizer installed above a hydronic boiler
Have these readyExisting boiler and capacityReturn-water temperatureFlue-gas temperatureOperating hours

Rainmaker hydronic economizer

Build your proposal.

Start with the existing boiler and the outcome you want. Specialized installation and engineering inputs are below.

01

Existing boiler

Select the boiler that Rainmaker will serve. If the make is unavailable, use the closest listed type or “To be Advised.”

Economizer arrangement
02

Performance goal

Efficiency-Match compares the proposed retrofit to a selected condensing boiler using the system water temperatures. For a custom target, switch it off and enter the desired flue-gas exit temperature.

Selection method
03

Water circuit

Use the actual entering-water temperature at the proposed Rainmaker. For comfort-heating systems, this is normally the return-water temperature.

Reset-water-temperature schedule
Use a reset schedule?
04

Operating profile

Enter gas temperature at 100% firing. Part-load temperatures can remain blank for Bruce to estimate. Adjust the hours and excess air to reflect the actual duty cycle.

Firing loadGas inlet tempHours/yearExcess air %
Firing load100%
Firing load
Firing load
Firing load
FGR takeoff location
05

Installation and economics

Draft inducer

Rainmaker construction is selected automatically. For standby oil firing, confirm the fuel, bypass strategy and gas-side materials with an engineer.

Bruce estimates the configuration and performance. Confirm application details with HeatSponge before ordering.

When the application needs more control

Additional options

These options use the same proposal engine and retain their default values until you change them.

01 / Fluid and efficiencyGlycol properties and current-boiler override
Override Bruce's boiler efficiency calculation?
02 / Maximum overall lengthLeave unrestricted unless space limits the design
Length limit, excluding piping connections
03 / Professional overridesBackpressure and custom exhaust flow

Use these only when the boiler's allowable backpressure and exhaust flow have been verified. Excess gas-side pressure drop can affect boiler operation.

Automatic selection

Bruce estimates the configuration and performance. Confirm application details with HeatSponge before ordering.