Heatcraft® Modular Auxiliary Removable Coil Unit (M.A.R.C. Unit)

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The Heatcraft® M.A.R.C. Unit (Modular Auxiliary Removable Coil Unit) is a versatile, factory-built cased coil system designed to provide flexibility, easy maintenance, and long-term performance. Unlike standard cased coil units, the M.A.R.C. Unit is engineered with a removable access panel, allowing the enclosed coil to be serviced or replaced without compromising the integrity of the case.

This innovative design reduces downtime, extends equipment life, and prevents costly replacements by enabling coil-only swaps instead of requiring an entirely new unit. All seams are sealed with silicone and weather-stripping, ensuring a durable, leak-free case suitable for demanding HVAC environments.

Key Applications of Heatcraft® M.A.R.C. Units:

  • Replacing coil sections in existing air handling units
  • Fitting tight-space applications or small door access situations (such as cruise ships or confined facilities)
  • Adding heating or cooling capacity to make-up air units
  • Providing auxiliary or supplemental heating/cooling in specialized environments

Every M.A.R.C. Unit is custom-built to specification, ensuring the right fit and performance for your project’s unique requirements.

Coil Section ConstructionAmericas
Tubing3/8”, 1/2” O.D. Cu & 5/8” O.D. Cu, CuNi, St Stl, Carbon Stl, AD Brass
Circuit TypeQuarter, Half, Three Quarter, Single, One and one half, Double, Triple or Custom
Rows1, 2, 3, 4, 5, 6, 8, 10, 12
Fin SurfaceSine Wave (corrugated), New Ripple (peak and valley) or Flat
Tube PatternsVarious
Casing / Mounting16 Gauge Galvanized or 304 Stainless Steel
ConnectionsCarbon Steel, Stainless Steel, Red Brass, Copper (Braze, MPT, FPT, Victaulic, Welded)
Vents & DrainsStandard
Fin MaterialAluminum, Copper all tube sizes
Stainless Steel, Carbon Steel – 5/8″ Only
OptionsDouble Wall, Filter Rack/Hinged Access, Removable Coil, Extended V & D, 3/4″ Insul.
LinksCertified Drawing: MarcUnit
Field Specification Drawing