MVB® Vertical Hydronic Boilers, 2503 - 4003

Time-honored technologies unite with cutting-edge advancements in Raypak’s MVB modulating vertical boiler.  Small space is no longer a problem, and our compact design fits through a 32” door opening to make it the perfect choice for those hard-to-reach retrofit projects.  The MVB is built to last, from the structural steel base to the stainless steel flue wrapper.  The built-in VERSA IC® Integrated Control platform precisely tracks the heating load to eliminate costly overshooting, and the 7:1 turndown ensures high efficiency throughout the firing rate and actually increases efficiency during part load, right when you want it. The 7" touchscreen makes programming and monitoring the unit simple.

Full Input in BTUH
Flue Dia.
 H7-2503   2,501,000 10"
 H7-3003   3,000,000  10"
 H7-3503   3,500,000  12"
 H7-4003   4,000,000  12"


  • 85% Thermal Efficiency at Full Rate; Up to 88.4% at Part Load.
  • Positive vent pressure, Condensing Appliance.  Cat IV Vent Required.
  • Bronze Headers with Copper Finned-Tube Heat Exchanger standard. Cupro-Nickel tubes available. ASME Section IV constructed and stamped, National Board registered.
  • CSA Low-Lead certified, less than 0.25% Lead.
  • Certified to ANSI Z21.13.
  • Minimum Inlet Water Temperature: 120°F.
  • Maximum Operable Outlet Water Temperature: 235°F.
  • Electronic Modulation, 7:1 Turndown.
  • VERSA IC® Control Package with Built-In Outdoor Reset Function and 7" touchscreen Display, Including System Sensor, Indirect Sensor & Indirect Supply Sensor.
  • Status Display Lights.
  • Cascade Control of up to 4 units, no external sequencer required.
  • Diagnostics Center with History, English, no codes.
  • Modbus RTU BMS port (RS485).
  • 0-10 VDC BMS Interface (Setpoint or Direct Drive).
  • All models indoor/outdoor construction.
  • Low NOx; consult local regulations.
  • Engineered with precisely matched system components.
  • Smallest installed footprint (11.7 square feet) design fits tight spaces and easily replaces larger boilers.
  • 100% Factory Fire Tested.
  • Complete cabinet protects all controls and wiring. Tough, rust-resistant powder-coat finish.
  • Suitable for altitudes up to 10,000 ft. (derate above 2,000 ft.).
  • No boiler condensate drain required (proprietary design)
  • Available for natural gas or propane.
  • Integral Combustion Air Filter (MERV8).
  • Multiple Pump Outputs – Boiler Pump, System Pump, Indirect Pump.
  • Whisper-Quiet Operation.
  • Proudly Assembled in the USA.



  • Outdoor air Sensor (B-32)
  • BACNet IP, BACnet MS/TP, Modbus TCP, N2 Metasys (B-85)
  • Lonworks (B-86)
  • Alarm with 4” Bell (E-5)
  • Low Water Cutoff (F-10)
  • Cold Water Protection
  • Condensate Neutralizer (Z-12)