AERCO Modulex EXT MLX 600
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.
Key figures
- Max input
- 642 MBH
- Max CSA output
- 609 MBH
- AFUE
- —
- Min input
- 46 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
AERCO Modulex EXT MLX 600 in practice
AERCO's Modulex EXT TDS prints the MLX EXT 600 at 46 MBH minimum input and 642 MBH maximum input with a 564,000–609,000 BTU/hr output range (Max Output varies with supply and return water temperatures). The ratings table lists an 87%–99% efficiency range; the TDS text states efficiency up to 98.6% can be achieved at the lowest firing rate.
The specifications table lists 14:1 turndown across 4 independent thermal modules, 2" NPT gas and 2 1/2" NPT water connections, 3.6 FLA at 120 V, a 4" air intake / 6" exhaust vent and air inlet, a 92 psi maximum allowed working pressure and 50°–180°F supply temperature control (35°F minimum inlet water). Dimensions are 40.6" × 30.3" × 45.3" with a 568 lb wet weight and 650 lb shipping weight.
The Modulex EXT is AERCO's outdoor-ready condensing line with a coated enclosure standard, sealed or room-air combustion, the Ufly touchscreen controller, Modbus integration and 10.5:1 to 39:1 operating range depending on the unit. It runs on natural gas or propane. No official Canadian-sales statement was found, so canadianStatus stays unknown.
Best suited to
- Commercial plants documenting an installed Modulex EXT MLX 600 against AERCO's TDS
- Hydronic systems in the 642 MBH input class
- Outdoor or space-constrained installations that need modular redundancy
Applicability and support
- Model number
- MLX EXT 600
- Canadian availability
- unknown
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
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.
Specifications
Published specifications
Values as published by AERCO (Watts). Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Min. input | 46 MBH | Min Input per the Modulex EXT TDS ratings table. |
| Max. input | 642 MBH | Max Input per the Modulex EXT TDS ratings table. |
| Output | ||
| Max. output | 609 MBH | TDS prints Max Output as 564,000–609,000 BTU/hr depending on supply and return temperatures; the upper figure is recorded here. |
| Efficiency | ||
| Efficiency (up to) | 98.6 % | The TDS states efficiency up to 98.6% can be achieved at the lowest firing rate; the ratings table prints an 87%–99% efficiency range for each model. |
| Efficiency range | 87–99 % | Efficiency Range per the Modulex EXT TDS ratings table. |
| Venting and air | ||
| Vent and air inlet size | 4" air intake / 6" exhaust | Per the Modulex EXT TDS specifications table; supports PVC, CPVC, polypropylene or AL29-4C venting. |
| Physical and connections | ||
| Gas connection | 2" NPT | Gas Connections per the Modulex EXT TDS specifications table. |
| Water connection | 2 1/2" NPT | Water Connections per the Modulex EXT TDS specifications table. |
| Width | 40.6 in | Per the Modulex EXT TDS dimensions table. |
| Depth | 30.3 in | Per the Modulex EXT TDS dimensions table. |
| Height | 45.3 in | Per the Modulex EXT TDS dimensions table. |
| Weight, wet | 568 lb | Weight (wet) per the Modulex EXT TDS dimensions table. |
| Weight, shipping | 650 lb | Weight (shipping) per the Modulex EXT TDS dimensions table. |
| Electrical | ||
| Electrical requirement (120 V) | 3.6 FLA | Electrical Req: 120V per the Modulex EXT TDS specifications table. |
| Operating limits and other | ||
| Turndown or operating range | 14:1 | Per the Modulex EXT TDS specifications table. |
| Thermal modules | 4 | Per the Modulex EXT TDS specifications table. |
Manuals
Alerts documented for this model
None documented yet.
Frequently asked questions
What are the Modulex EXT MLX 600 ratings?
AERCO's TDS prints 46 MBH minimum input, 642 MBH maximum input, a 564,000–609,000 BTU/hr output range and 14:1 turndown across 4 thermal modules.
Is the Modulex EXT MLX 600 outdoor-rated?
AERCO's TDS states the Modulex EXT comes standard with a coated enclosure allowing outdoor installations.
What fuel does the Modulex EXT MLX 600 use?
Natural gas or propane, per the Modulex EXT TDS specifications table.
Questions about the AERCO Modulex EXT MLX 600?
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.
Compare and explore
- AERCO Modulex EXT 450 vs Modulex EXT 600Comparison
- AERCO Modulex EXT MLX 450Same series
- AERCO Modulex EXT MLX 800Same series
- AERCO Modulex EXT MLX 1100Same series
- AERCO Modulex EXT MLX 1500Same series
- AERCO Modulex EXT MLX 2300Same series
- AERCO Modulex EXT MLX 2600Same series
- AERCO Modulex EXT MLX 3000Same series
- Modulex EXT series hub
- Buying guide
Sources and verification
- AERCO Modulex EXT 450–1100 Boilers Technical Data Sheet (PDF) · accessed September 9, 2026
- AERCO Modulex EXT Ufly Controller Manual, OMM-0159 (PDF) · OMM-0159 · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.