Crown Mega-Flex
Model Number: MFX
Versatile cast iron boiler for budget-conscious installations.
Technical Specifications
Prices depend on sizing, venting and piping in your home, so we quote every installation.
Sizing: the right size comes from a room-by-room heat-loss calculation, not the size of the old boiler or a rule of thumb. Oversized boilers short-cycle and waste fuel; steam systems are sized to the connected radiation instead. See how we approach boiler installation.
Home-Specific Operating Cost Review
No guaranteed annual savings or payback period
Historical Use
Fuel consumption and weather
Current Rates
Utility and delivered-fuel prices
System Design
Load, piping, controls, and temperatures
Full Specifications
- Model Number
- MFX
- Efficiency (AFUE)
- 85%
- Boiler Type
- Hot Water Boiler
- BTU Input Range
- 42k - 175k BTU
- In Production
- Yes
- Parts Warranty
- 2 years
- Heat Exchanger Warranty
- 20 years
Specification source not yet linked — figures are being verified against manufacturer data.
Ideal For
Rental properties and investment homes
Expert Review: Crown Mega-Flex
The Crown Mega-Flex offers versatile installation options at budget-friendly pricing. This cast iron hot water boiler adapts to tight basement configurations common in older Nassau County homes. Direct vent or power vent options provide flexibility when chimney access is limited.
At 85% AFUE, the Mega-Flex won't qualify for efficiency rebates, but the lower upfront cost appeals to budget-conscious homeowners and landlords. Parts are universally available at every local supply house.
The compact footprint fits basement utility areas where space is at a premium. Multi-fuel capability provides flexibility for homes in areas with limited natural gas service.
The 20-year heat exchanger warranty covers the cast iron construction for long-term peace of mind.
Our recommendation: The Mega-Flex is best suited for budget-conscious installations where space is tight and chimney access is limited. The versatile venting options solve installation challenges that might otherwise require expensive modifications.
Key Features & Technology
Flexible installation options
Cast iron durability
Direct or power vent
Multi-fuel capable
Compact footprint
Advantages
- Versatile installation options
- Budget-friendly cast iron
- Good for tight spaces
- Landlord approved reliability
Considerations
- 85% AFUE lower efficiency
- Basic technology
- No advanced controls
Sizing & Installation Notes
Hot water boilers like the Mega-Flex are sized from a room-by-room heat-loss calculation. We never match the old boiler's size — oversized units short-cycle, waste fuel and wear out years early.
Every Crown Boiler installation starts with a free in-home assessment covering the heat-loss calculation, venting and chimney condition, and gas or oil supply sizing. Learn more about our boiler installation process, or see current rebate and incentive programs that may apply.
Warranty & Protection
Parts Warranty
2 years
Heat Exchanger
20 years
Our Guarantee
100% Satisfaction
All Crown Boiler boiler installations by Home+ Air & Heat include our 1-year workmanship warranty, covering labor and any installation-related issues.
Compare the Crown Boiler Lineup
| Model | Efficiency | BTU Range | Fuel | Heat Exchanger Warranty |
|---|---|---|---|---|
| Mega-Flex (this model) | 85% AFUE | 42k - 175k BTU | — | 20 years |
| Bermuda BWC | 87% AFUE | 42k - 252k BTU | — | 20 years |
| Aruba | 82% AFUE | 70k - 196k BTU | — | 20 years |
| Velocity Phantom-X | 95% AFUE | 8k - 210k BTU | natural gas/propane | 12 years |
| Aruba 5 | 84% AFUE | 70k - 295k BTU | natural gas/propane | 12 years |
| Bimini BWC | 95% AFUE | 30k - 300k BTU | natural gas/propane | 15-year limited |
| Freeport 2 | 86% AFUE | 91k - 158k BTU | oil | 12 years |
| Freeport CT | 85% AFUE | 105k - 196k BTU | oil | limited lifetime |
| Tobago | 86% AFUE | 91k - 158k BTU | oil | 12 years |
| Tobago (TWZ) | 86.1% AFUE | 70k - 210k BTU | oil | 12-yr limited |
| Cayman | 83.5% AFUE | 103k - 379k BTU | natural gas | limited lifetime; verify current Cayman terms |
| Phantom II | 95% AFUE | 8k - 180k BTU | natural gas/propane | 12-year limited |
| Phantom II Combi | 95% AFUE | 14k - 200k BTU | natural gas/propane | 12-year limited |
| Velocity Phantom Combi | 95% AFUE | 16k - 199k BTU | natural gas/propane | 12-year limited |
| Bali | 84% AFUE | 61k - 229k BTU | natural gas | 12 years |
| Bermuda | 82% AFUE | 103k - 276k BTU | natural gas | 12 years |
| Bermuda (BSI) | 82.5% AFUE | 69k - 380k BTU | natural gas/propane | 12-yr limited |
| Freeport 2 (FSZ) | 83.3% AFUE | 80k - 160k BTU | natural gas/propane | 12-yr limited |
| Kingston (KSZ) | 85.4% AFUE | 59k - 176k BTU | oil | 12-yr limited |
| Cabo 2 | 84% AFUE | 83k - 245k BTU | natural gas/propane | 12 years |
| Aruba | 83.3% AFUE | 38k - 280k BTU | natural gas/propane | limited lifetime |
See the full Crown Boiler brand page for lineup context, or browse the Best Hot Water Boilers 2027 guide to compare across brands.
Frequently Asked Questions
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