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MVB Modulating Vertical Water Heaters 503A-2003A

MVB Modulating Vertical Water Heaters 503A-2003A

Time-honored technologies unite with cutting-edge advancements in Raypak’s MVB modulating vertical water heater. 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.


  • 87% Thermal Efficiency at Full Rate.
  • Positive vent pressure, Condensing Appliance.  Cat IV Vent Required.
  • Bronze headers with copper finned tube heat exchanger standard. Cupro-Nickel tubes available as options. ASME Section IV constructed and stamped, National Board registered.
  • CSA Low-Lead certified, less than 0.25% Lead.
  • Certified to ANSI Z21.10.3.
  • Minimum Inlet Water Temperature: 120°F.
  • Maximum Setpoint: 160°F.
  • Full electronic modulation, 60% min fire under normal conditions
  • VERSA IC® Control Package with LCD Display.
  • Status Display Lights.
  • Cascade control of up to 8 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.
  • Certified under SCAQMD Rule 1146.2.  Meets all Low NOx regulations.
  • Engineered with precisely matched system components.
  • Smallest installed footprint (5.4 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.
  • Whisper-Quiet Operation.
  • Proudly Assembled in the USA.


  • 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 Run
  • Condensate Neutralizer (Z-12)
    • 87% Thermal Efficiency at Full Rate 
    • 100% Factory fire-tested 
    • VERSA IC® Modulating controller with 7" color touchscreen display 
    • Raymote™ remote connectivity provided standard 
    • On/Off firing with soft-start ignition 
    • Full safety diagnostics with history 
    • Status display lights 
    • Cascade up to 8 heaters – no external sequencer required 
    • Modbus RTU BMS Port 
    • CSA Low-Lead Certified ≤ .25% Lead 
    • Maximum outlet water temperature: 200°F (93.3°C) 
    • Maximum tank setpoint: 160°F (71.1°C) 
    • Minimum acceptable inlet water temperature: 120°F (48.9°C) 
    • Limited 20-year thermal shock warranty 
    • Limited 5-year copper/10-year cupronickel heat exch. warranty 
    • SCAQMD Rule 1146.2 certified, Low NOx < 20 ppm 
    • Must be used with properly-sized storage tank for proper operation 
    • Proudly assembled in the USA
Technical specification
  • Unique ref.MVB-Modulating-Vertical-Water-Heaters-503A-2003A
  • Product familyBoilers & Water Heaters
  • Product groupDomestic Hot Water Heaters
  • TypeObject (single object)
  • Date of publishing2020-10-01
  • Edition number1
  • Designed inUnited States
  • Manufactured inUnited States
  • BIMobject CategoryHVAC - Water heaters
  • IFC classificationHeat Exchanger
  • ETIM CodeEC010868
  • ETIM NameGas-fired water heater
  • UNSPSC nameDomestic water heaters
  • UNSPSC code40101825
  • Uniclass 2015 CodePr_60_60_96
  • Uniclass 2015 DescriptionWater heaters
  • CSI MasterFormat 2014 Code22 34 00
  • CSI MasterFormat 2014 TitleFuel-Fired Domestic Water Heaters
  • OmniClass Number23-31 29 00
  • OmniClass TitleHot Water Heaters
  • CSI UniFormat II CodeD3090
  • CSI UniFormat II TitleOther HVAC Systems & Equipment

Region availability

North America
United States