Thermo2000 DoubleMax™ 80-5 Instantaneous Indirect Double-Wall Water Heater
Deliver continuous, on-demand domestic hot water with absolute safety—even when using closed-loop or potentially toxic heat-transfer fluids. The DoubleMax™ 80-5 combines an advanced double-wall copper heat exchanger with an 80-gallon buffer tank to ensure high flow rates, minimal standby loss, and total protection against cross-contamination.
Key Features
- Double-Wall Copper Heat Exchanger
30.9 sq ft of surface area for rapid, efficient heat transfer without any risk of mixing boiler fluid and potable water. - Instantaneous Hot Water Delivery
Up to 15 gpm at a 70 °F rise—eliminating storage-tank limitations and meeting peak demands. - Robust 80 US‐Gallon Buffer Tank
Smooths temperature fluctuations and supports intermittent draw patterns in commercial or multi-dwelling installations. - High Working Pressure
Rated for 150 psi maximum, compatible with a wide range of hydronic systems. - Standard Connections
1½″ copper sweat female domestic ports and 1½″ NPT male heating-loop ports for straightforward integration. - Exceptional Efficiency & Low Standby Loss
< 0.5 °F heat loss per hour with 99 % heat-transfer efficiency.
Technical Specifications
| Specification | Value |
|---|---|
| Model | DoubleMax™ 80‑5 |
| Heat Exchanger Area | 30.9 sq ft |
| Buffer Tank Volume | 80 US gallons |
| Maximum Working Pressure | 150 psi |
| Domestic Water Connections | 1½″ Copper Sweat Female |
| Heating Water Connections | 1½″ NPT Male |
| Height × Diameter | 73‑3/4″ × 24″ |
| Equipment Weight | 355 lbs |
| Shipping Weight | 440 lbs |
| Standby Loss | < 0.5 °F/hr |
| Heat-Transfer Efficiency | 99 % |
Performance (at 40 °F inlet, 180 °F supply)
| Power (BTU/h) | kW | 110 °F 1st Hour | 110 °F Continuous | 140 °F 1st Hour | 140 °F Continuous | 160 °F 1st Hour | 160 °F Continuous |
| 50,000 | 15 | 166 | 86 | 92 | 60 | 74 | 60 |
| 100,000 | 29 | 252 | 172 | 152 | 120 | 134 | 120 |
| 150,000 | 44 | 338 | 258 | 213 | 181 | 194 | 181 |
| 200,000 | 59 | 424 | 344 | 273 | 241 | 254 | 241 |
| 250,000 | 73 | 510 | 430 | 333 | 301 | — | — |
| 300,000 | 88 | 596 | 516 | 393 | 361 | — | — |
| 350,000 | 103 | 682 | 602 | 454 | 422 | — | — |
| 400,000 | 117 | 768 | 688 | — | — | — | — |
| 450,000 | 132 | 855 | 775 | — | — | — | — |
| 500,000 | 147 | 941 | 861 | — | — | — | — |
| Values based on 40 °F domestic inlet and 180 °F boiler supply temperatures. |
Applications & Benefits
- Commercial & Multi-Unit Housing: Ideal for hotels, apartments, and institutional facilities requiring uninterrupted high-volume hot water.
- Hydronic System Integration: Safely pairs with glycol or closed-loop primary systems without cross-contamination risk.
- Energy Savings: Instantaneous operation plus minimal standby loss reduces fuel consumption and operating costs.
- Long-Term Reliability: Durable double-wall exchanger and robust construction ensure decades of maintenance-free service.