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AERCO (Watts) · Series
The AERCO Modulex EXT is a condensing, fully modulating multi-module boiler (independent thermal modules) available in eight MLX EXT sizes from 450 to 3000 MBH, with low NOx (under 20 ppm), an outdoor-ready standard enclosure, whisper-quiet operation and the Ufly colour-touchscreen control.
Series facts
The TDS states efficiency up to 98.6% can be achieved at the lowest firing rate (46,000 BTU/hr input on the 450–1100 range); the ratings table prints an 87%–99% efficiency range for each model.
AERCO sells the Modulex EXT as a condensing, fully modulating boiler built from independent thermal modules. The published TDS ratings tables print eight sizes: MLX EXT 450, 600, 800 and 1100 (each combining 160,500 BTU/hr thermal modules, 46,000–1,123,500 BTU/hr operating range) and MLX EXT 1500, 2300, 2600 and 3000 (383 MBTU/hr thermal modules, 83,000–3,060,000 BTU/hr operating range).
The TDS headlines low NOx (under 20 ppm), sound levels under 50 dBa, an outdoor-ready standard powder-coated enclosure, turndown from 10.5:1 up to 39:1 depending on unit, and efficiency up to 98.6% at the lowest firing rate (87%–99% range per model). The control is the Ufly colour touchscreen, and the TDS documents PVC, CPVC, polypropylene or AL29-4C venting, sealed or room-air combustion and Modbus integration to a BAS.
The 450–1100 and 1500–3000 TDS and the OMM-0158/0159/0160 Ufly manuals are linked from the live official document system (verified 2026-09-09). No official Canadian statement was found, so canadianStatus is recorded as unknown.
Highlights
Models
One canonical page per model with input, output and efficiency kept separate.
AERCO (Watts)
The AERCO Modulex EXT MLX 450 is a condensing multi-module commercial boiler rated 481.5 MBH maximum input and a 422,000–457,000 BTU/hr output range in AERCO's published ratings table, with 10.5:1 turndown across 3 independent thermal modules and a 454 lb wet weight.
AERCO (Watts)
The AERCO Modulex EXT MLX 600 is a condensing multi-module commercial boiler rated 642 MBH maximum input and a 564,000–609,000 BTU/hr output range in AERCO's published ratings table, with 14:1 turndown across 4 independent thermal modules and a 568 lb wet weight.
AERCO (Watts)
The AERCO Modulex EXT MLX 800 is a condensing multi-module commercial boiler rated 802.5 MBH maximum input and a 707,000–762,000 BTU/hr output range in AERCO's published ratings table, with 17.5:1 turndown across 5 independent thermal modules and a 634 lb wet weight.
AERCO (Watts)
The AERCO Modulex EXT MLX 1100 is a condensing multi-module commercial boiler rated 1123.5 MBH maximum input and a 993,000–1,067,000 BTU/hr output range in AERCO's published ratings table, with 24.5:1 turndown across 7 independent thermal modules and a 826 lb wet weight.
AERCO (Watts)
The AERCO Modulex EXT MLX 1500 is a condensing multi-module commercial boiler rated 1530 MBH maximum input and a 1,334,000–1,476,000 BTU/hr output range in AERCO's published ratings table, with 19.6:1 turndown across 4 independent thermal modules and a 1137 lb wet weight.
AERCO (Watts)
The AERCO Modulex EXT MLX 2300 is a condensing multi-module commercial boiler rated 2295 MBH maximum input and a 2,001,000–2,215,000 BTU/hr output range in AERCO's published ratings table, with 29:1 turndown across 6 independent thermal modules and a 1384 lb wet weight.
AERCO (Watts)
The AERCO Modulex EXT MLX 2600 is a condensing multi-module commercial boiler rated 2677 MBH maximum input and a 2,334,000–2,583,000 BTU/hr output range in AERCO's published ratings table, with 34:1 turndown across 7 independent thermal modules and a 1549 lb wet weight.
AERCO (Watts)
The AERCO Modulex EXT MLX 3000 is a condensing multi-module commercial boiler rated 3060 MBH maximum input and a 2,668,000–2,951,000 BTU/hr output range in AERCO's published ratings table, with 39:1 turndown across 8 independent thermal modules and a 1664 lb wet weight.
| Specification | AERCO Modulex EXT MLX 450 | AERCO Modulex EXT MLX 600 | AERCO Modulex EXT MLX 800 | AERCO Modulex EXT MLX 1100 | AERCO Modulex EXT MLX 1500 | AERCO Modulex EXT MLX 2300 | AERCO Modulex EXT MLX 2600 | AERCO Modulex EXT MLX 3000 |
|---|---|---|---|---|---|---|---|---|
| Min. input | 46 MBH | 46 MBH | 46 MBH | 46 MBH | 83 MBH | 83 MBH | 83 MBH | 83 MBH |
| Max. input | 481.5 MBH | 642 MBH | 802.5 MBH | 1,123.5 MBH | 1,530 MBH | 2,295 MBH | 2,677 MBH | 3,060 MBH |
| Max. output | 457 MBH | 609 MBH | 762 MBH | 1,067 MBH | 1,476 MBH | 2,215 MBH | 2,583 MBH | 2,951 MBH |
| afue | — | — | — | — | — | — | — | — |
| Turndown or operating range | 10.5:1 | 14:1 | 17.5:1 | 24.5:1 | 19.6:1 | 29:1 | 34:1 | 39:1 |
| vent-max-3 | — | — | — | — | — | — | — | — |
| vent-max-2 | — | — | — | — | — | — | — | — |
| Weight, wet | 454 lb | 568 lb | 634 lb | 826 lb | 1,137 lb | 1,384 lb | 1,549 lb | 1,664 lb |
Read the full comparison: AERCO Modulex EXT 450 vs Modulex EXT 600 →
Read the full comparison: AERCO Modulex EXT 800 vs Modulex EXT 1100 →
Read the full comparison: AERCO Modulex EXT 1500 vs Modulex EXT 2300 →
Read the full comparison: AERCO Modulex EXT 2600 vs Modulex EXT 3000 →
Error codes and alerts
No alerts documented for this series yet.
Manuals
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Services for AERCO (Watts) boilers
The TDS says the Modulex EXT comes standard with a coated enclosure allowing outdoor installations.
AERCO's TDS prints MLX EXT 450, 600, 800, 1100, 1500, 2300, 2600 and 3000.
The TDS prints natural gas or propane. Fuel conversion is a gas-fitting task for a licensed contractor.
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.