← Boilers
Multi Pass Series
Triple-Pass Heat Exchanger. Turbo Draft Secondary Burn. Traditional outdoor furnace built for a cleaner burn.
409 Titanium Enhanced Stainless Steel • American Made in International Falls, MN • 20-Year Warranty
Triple-Pass Heat Exchanger. Turbo Draft Secondary Burn. Traditional outdoor furnace built for a cleaner burn.
409 Titanium Enhanced Stainless Steel • American Made in International Falls, MN • 20-Year Warranty
A proven triple-pass design paired with airflow and ash-handling features that keep the fire hot and maintenance simple.
Three water-filled passes pull more heat before reaching the chimney.
Shaker grates drop ash into a removable pan, no tools needed.
Industrial fans and actuator ensure consistent operation for years to come.
Secondary air above the flame burns off gases before they escape.
Insulated, roller-latch door seals tight at a comfortable loading height.
Illuminated digital display is easy to read and a dial to fine-tune the burn.
The Turbo Draft System blows fresh air in above the flame, pushing secondary gases back down into the fire, where they ignite before the exhaust enters the triple-pass heat exchanger. That second burn raises fire temperatures and recovers more heat, and it reduces the gases that lead to creosote buildup.
Water-Filled Heat Exchanger
Exhaust Temperature
Largest Model (7500MP)
More usable heat recovered from every load of fuel helps keep heating costs down.
Secondary gases burn above the flame for hotter fires and less of the exhaust that leads to creosote.
Made in the USA from 409 Titanium Enhanced Stainless Steel and covered by a 20-year limited warranty.
Shaker grates, an extra-large ash pan, and accessible cleanout doors make routine cleaning quick.
Adjustable air, digital controls, a water level indicator, and a big firebox keep day-to-day operation straightforward.
Cast iron grates and thick stainless steel built to withstand coal temperatures while still burning wood beautifully.
A look inside the Multi Pass firebox, grates, and heat exchanger.
Extra-large, insulated loading door with a double safety-latch handle.
Easy access to the ash pan, also secured with a double safety latch.
Opens up the heat exchanger for clearing fly ash.
Support a complete burn and help sift ash out of the fire.
Extra-large and removable for easy emptying.
Pushes air above the flame so secondary gases burn before they reach the chimney.
Three passes for better heat transfer than a conventional single-pass unit.
Supplies air under the shaker grates for a hotter, cleaner burn.
Class A insulated chimney.
Centralized outdoor heat for your home, with fuel, ash, and smoke kept outside.
Heat pools and hot tubs as part of a properly designed hydronic system.
Supplies domestic hot water when installed with the right heat exchanger.
Steady hydronic heat through radiant floors in homes, shops, and garages.
A properly sized unit can heat medium to large commercial buildings.
Helps hold the consistent temperatures plants need.
Keeps detached shops and garages comfortable all winter.
Heat for barns, livestock buildings, and other farm structures.
Compare the five Multi Pass models.
Spec
7200MP
7300MP
7350MP
7400MP
7500MP
Estimated Weight
1,450 lbs
1,800 lbs
2,050 lbs
2,500 lbs
4,000 lbs
Width
49″
53″
55″
61″
89″
Length
61″
70″
77″
81″
102″
Height
87″
90″
96″
100″
110″
Firebox Length
30″
38″
44″
48″
60″
Chimney Size
6″
6″
6″
8″
10″
Door Size
20″ × 20″
20″ × 20″
20″ × 24″
24″ × 24″
42″ × 30″
Supply Size
1 – 1¼″
2 – 1¼″
2 – 1¼″
2 – 1¼″
4 – 1¼″
Return Size
1 – 1¼″
2 – 1¼″
2 – 1¼″
2 – 1¼″
4 – 1¼″
Water Capacity
140 gal
180 gal
260 gal
320 gal
600 gal
Approximate Coverage (sq ft)
2,000–3,000
4,000–6,000
6,000–8,000
8,000–10,000
18,000–20,000
BTUs
165,000
275,000
350,000
400,000
750,000
Exhaust gases make three passes through the water-filled heat exchanger before leaving the chimney, so more of their heat ends up in the water jacket instead of going up the flue.
Multipass series boiler is designed for burning a wide range of fuels including coal, wood, and other biomass. It is not designed to burn garbage, rubber, plastics or other non-approved fuels. Check the owners manual for additional details.
Multi Pass is a traditional triple-pass furnace designed for coal and wood. Pristine is a gasification boiler built to burn seasoned cordwood at the highest efficiency and lowest emissions.
See the Pristine Series →Both the Multi Pass and Pristine are designed for about 12-hour burn times when the unit is sized correctly for your heating load.
Plan on emptying the ash pan weekly and cleaning the heat exchanger every two to three weeks. Once a coal bed is established, shake the grates about once a week.
Yes. Power runs the blowers, circulating pumps, and controls.
Every Multi Pass Series furnace is covered by Crown Royal's 20-year limited warranty.
Full warranty details →It depends on square footage, insulation, and everything else you want to heat, like hot water or a second building. Contact us and we'll help you size it right, with a site visit if needed.