A breakthrough in high-efficiency design, this line of condensing and fully modulating boilers supports 300,000 to 1 million Btu/hr. hydronic heating systems while delivering a greater degree of operating reliability for customer peace-of-mind.

To achieve the greatest possible fuel savings, each boiler combines independent, 151,500 BTU/hr. thermal modules that operate to deliver superior turndown and a range of non-cycling operation not readily achieved by competitive equipment or controls. Six units are available:

In addition to minimizing the redundant capacity needed for any project, these quiet and lightweight boilers can support low NOX and low gas pressure applications as well as PVC venting materials. Each unit enclosure offers multiple supply/return piping and venting locations for installation flexibility and allows for multiple units to be easily co-located for greater than 1 million Btu/hr. applications. Combustion view ports and easy access to all operating components further simplify minimal maintenance requirements.

Unmatched Operating Efficiency
Operating efficiency is influenced by the firing rate and return water temperature delivered to each Modulex boiler. The following chart outlines efficiency at 100% fire under BTS-2000 test conditions.

Revolutionary Design
Depending on unit size, each AERCO Modulex boiler contains between two and seven, pre-assembled thermal modules housed within a common enclosure. Each standalone, 151,500 BTU/hr. thermal module features:

• a controller with built-in combustion safeguard;
• a variable speed fan;
• a modulating gas valve;
• an electronic iginition with flame detector;
• radiating, pre-mix, >3:1 modulating burner;
• flow temperature sensor;
• overtemperature limiting thermostat;
• cast aluminum heat exchanger.

The operation of each 151,500 BTU/hr. thermal module is regulated by its own dedicated controller located internally along the front panel of the unit. Equipped with a combustion safeguard, each of these controllers drives the fan speed, gas delivery, burner turndown, etc. for its corresponding thermal module. All the individual thermal controllers are linked in a slave-to-master relationship with the boiler’s master controller. It is the master controller which drives or bypasses one or more thermal modules based on the total system load and in response to operating feedback received from each thermal module controller.

Enhanced Efficiency & Reliabilty
The independent operation of two or more thermal modules increases each boiler’s turndown range while also increasing its overall reliability. And since thermal efficiency increases as firing rates drop, the simultaneous low-fire operation of multiple modules also ensures that Modulex boilers continuously maximize operating efficiency.

For example, the MLX-1060 combines the power of seven thermal modules – each operating with greater than 3:1 turndown to deliver a 23:1 range of operations. From the low fire input of a single module (45,500 BTU/hr.) to the unit’s full fire capacity (1,060,000 BTU/hr.), the boiler precisely matches load without cycling or temperature overshoot. Importantly, it does so by always employing as many modules as possible – each firing at its lowest possible firing rate. Less energy is required for the group of thermal modules, each firing at part load, to heat a building than if only some modules, each operating at full fire, carried the entire load. Consequently, this controls approach results in greater fuel savings than if each thermal module reached its full 151,500 BTU/hr. capacity before the next module came on line.

In the event that one module is not working correctly, the remaining modules – hence the boiler unit – will continue to operate. Independently operating thermal modules deliver built-in redundancy to the boiler through the availability of multiple combustion safeguards, burners, gas valves, blowers, etc. Such a design approach is unique in the industry and can significantly reduce the need for redundant system capacity.

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