Thermo2000 DoubleMax™ 50-4
Instantaneous Indirect Double-Wall Water Heater
Deliver continuous, on-demand domestic hot water with unmatched safety and efficiency. The DoubleMax™ 50-4 combines a durable 50-gallon buffer tank with a patented double-wall copper heat exchanger for reliable performance in commercial and multi-residential applications. Ideal for installations requiring compact design, low maintenance, and maximum protection against cross-contamination.
Key Benefits
-
Double-Wall Copper Heat Exchanger
24.7 sq ft of high-conductivity surface ensures rapid, safe heat transfer between boiler fluid and potable water. -
Instantaneous Hot Water Production
Up to 12 GPM at a 70 °F rise—perfect for peak demand periods without large storage requirements. -
Efficient 50-Gallon Thermal Buffer
Reduces temperature swings and supports intermittent draw profiles in smaller systems. -
Compact, High-Pressure Design
Operates up to 150 psi with a space-saving vertical form factor. -
Low Standby Loss
< 0.5 °F/hour standby loss and 99% heat transfer efficiency maximize energy savings. -
No Scale or Corrosion
Copper coil design minimizes maintenance and eliminates the need for sacrificial anodes or tank lining inspections. -
Multi-Energy Compatibility
Works with gas, electric, wood, oil, and solar thermal sources.
Technical Specifications
| Specification | Value |
|---|---|
| Model | DoubleMax™ 50-4 |
| Buffer Tank Volume | 50 US gallons |
| Heat Exchanger Area | 24.7 sq ft |
| Max Domestic Flow Rate | 12 GPM |
| Maximum Working Pressure | 150 psi |
| Domestic Water Connections | 1½″ Copper Sweat (Female) |
| Heating Water Connections | 1¼″ NPT (Male) |
| Height × Diameter | 59¼″ × 22″ |
| Unit Weight | 260 lbs |
| Standby Heat Loss | < 0.5 °F/hr |
| Heat Transfer Efficiency | 99% |
| Max Output Temp | Up to 200 °F |
Performance Data
Based on 40 °F inlet and 180 °F boiler supply
| BTU/h | kW | 110 °F First Hour | 110 °F Continuous | 140 °F First Hour | 140 °F Continuous | 160 °F First Hour | 160 °F Continuous |
|---|---|---|---|---|---|---|---|
| 50,000 | 15 | 136 gal | 86 gal | 80 gal | 60 gal | 69 gal | 60 gal |
| 100,000 | 29 | 222 gal | 172 gal | 140 gal | 120 gal | 129 gal | 120 gal |
| 150,000 | 44 | 308 gal | 258 gal | 201 gal | 181 gal | 189 gal | 181 gal |
| 200,000 | 59 | 394 gal | 344 gal | 261 gal | 241 gal | — | — |
| 250,000 | 73 | 480 gal | 430 gal | 321 gal | 301 gal | — | — |
| 300,000 | 88 | 566 gal | 516 gal | 381 gal | 361 gal | — | — |
| 350,000 | 103 | 652 gal | 602 gal | — | — | — | — |
| 400,000 | 117 | 738 gal | 688 gal | — | — | — | — |
Applications
- Multi-unit residential buildings
- Small commercial facilities
- Institutional installations
- Hydronic systems with closed-loop or glycol heating
- Retrofit systems seeking bacteria-resistant hot water production
Warranty
- 15-Year Residential Warranty (Tank + Copper Coils)
- 10-Year Commercial Warranty (Tank + Copper Coils)
- 2-Year Warranty on Mechanical Components