Hot Water Heating


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P-K MACH CM Series Condensing Boilers

Models: CM300 (300 MBTU), CM399 (399 MBTU), CM500 (500 MBTU)

Strapped for space? Look no further than our redesigned line of smaller P-K MACH® CM Series boilers, ranging from 300 to 500 MBTU/hr.

P-K MACH® CM Series boilers are CSA-certified at >90% efficiency to lower operating costs and low NOx to promote sustainability. They are the ideal condensing boilers for a multitude of commercial, industrial, and institutional applications.

Harsco Industrial Patterson-Kelley does it again!   We have managed to make the smallest condensing boiler even smaller.   Our new and improved P-K MACH®  CM Series boilers require 40% less space than their predecessor.

Versatile piping connections, zero clearance and a wall hanging option make these boilers the perfect solution for any retrofit project.  Do you have a small mechanical room, height restrictions or difficult entry? P-K MACH®  CM Series boilers fit into the tightest of spaces.

The right size for any requirement.

Wall Mount or Floor Standing

When compared to previous models, the redesigned P-K MACH® CM300 to CM500 MBTU/hr boilers feature a 40% smaller footprint, improved serviceability, and NEW wall hung option. The top and front panels of the boilers are fully removable to allow for easy access to key components. Multiple connection orientations located on the bottom of the unit allow plumbing and electrical to come in from any direction, while zero clearance to combustibles reduce the space required when multiple boilers are installed.


Better Access

Any way you look at it, it’s easier to maintain

cmseries-bodyA wider cabinet allows for better access to serviceable parts, while a shorter cabinet depth helps create a safer wall mount profile.

The P-K EVNI® control does it all.

The integrated P-K ENVI® control, standard on all P-K MACH® boilers, monitors and modulates the combustion and ignition of the boiler to maintain the desired outlet temperature. When multiple boilers are installed together, the lead-lag setup and boiler start rotation ensures run times are equally distributed across each unit in the system, extending the life of the boilers. The P-K ENVI® control can connect with most building management systems via the optional protocol converter.


  • Runs on natural gas or liquid propane
  • Versatile piping arrangements
  • >90% CSA certified efficiency
  • Wall mounting bracket (optional)
  • Low NOxemissions on standard boiler
  • 12″(standard) or 18″ floor stand (optional)
  • Small footprint
  • ENVI control
  • Removable front panel and top service access panel
  • Protocol converter (optional) for LONWORKS, BACNET or METASYS N2
  • Zero clearance


  • Average energy savings of 25-30%
  • Arrange multiple boilers side by side on the wall or back to back on the floor to maximize the available space in small mechanical rooms
  • Low emissions at no extra cost
  • Standard12″ floor stand fits under most existing piping or height restricted areas in retrofit projects
  • 40% smaller footprint than its predecessor, the P-K MACH C300-C450 which are no longer in production
  • Directly integrates with building management systems (MODBUS) using on-board control; no additional equipment required
  • Ease of service reduces maintenance time and cost



For more information about this or any of our other products, please contact us or click here to find your authorized Harsco Industrial Patterson-Kelley representative.

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