XTherm® Condensing Water Heaters, 1005A-2005A

The proven XTherm - vertical modulating condensing heater in sizes to 2000MBTU. XTherm combines time-honored high-recovery copper fin technology with cutting edge control and combustion advancements. The installer and building owner enjoy broad installation flexibility, easy commissioning, optimum seasonal efficiency, and long term reliability.

Remarkably small footprint saves space for those cramped retrofit projects. Built to last, with industrial grade construction and user friendly serviceability. Extreme burner turn down produces up to 99% efficiency at low fire when it's most needed. Meets even 2012 LoNOx standards. Now is the time to take a closer look at Raypak's XTherm.

XTherm products take their jobs seriously. On the outside the muscular powder coated steel cabinet provides clean proportions with a strong, unrivaled weather-resistant design. A look on the inside reveals the XTherm's hybrid heat exchanger system design. Our vertically stacked and robust copper main heat exchanger delivers maximum non-condensing efficiency that works seamlessly with our state-of-the-art-stainless steel commercial-grade condensing heat exchanger. Maximum synergy is maintained throughout the complete XTherm heat exchange system with Raypak's proven Cold Water Protection System, a proven design approach that ensures the XTherm is built for even the longest days of work, while saving the maximum amount of energy every time it is used.

Model Number Full Input in
 Flue Dia.
WH7-1005A 999,000
WH7-2005A 1,999,000


  • 97% efficiency.  Condensing, Cat IV venting required.
  • Brass headers and pumps with copper finned-tube primary heat exchanger.  Cupro-nickel tubes available as options.  CSA Low Lead Certified 0.25% lead
  • Minimum continuous inlet water temperature (50°F)
  • Electronic modulating gas valve and burner, up to 7:1 turn down
  • Small footprint, less than 11 square feet
  • On-board diagnostic center, real English, no codes
  • All models indoor/outdoor construction
  • Complete cabinet protects all controls and wiring
  • Certified under SCAQMD rule 1146.2. Meets all Low NOx regulations.
  • Suitable for altitudes up to 10,000 ft. (derate above 5,000 ft.)
  • Primary-secondary piping required.
  • 0-10 VDC Remote set-point BMS Interface
  • 0-10 VDC Direct Drive
  • Available for natural gas or propane.
  • VERSA IC® control package.
  • Built-in cascade function for up to 4 heaters.
  • Modbus® RTU port (RS485).


  • BACNet IP, BACnet MS/TP, Modbus TCP, N2 Metasys (B-85)
  • Lonworks (B-86)
  • Centrotherm® Polypropylene Vent Adapter (D-33)
  • Alarm with 4” Bell (E-5)
  • Low Water Cutoff (F-10)
  • Condensate Neutralizer (Z-12)
  • PVC Vent (Factory-Installed ONLY) (D-32)

    1. Low Voltage Wiring Terminal

    Up front and easy to get to. Makes sensor wiring andBMS wiring simple and clean.

    2. Versa IC Board

    The Versa IC, Integrated Control system is CSA listedand certified as a combined temperature, safety, andignition control device. Easy front access to all fieldwiring. This includes outdoor sensor, DHW sensor, systemalarm, Modbus BMS port and 0-10V DC input connections.Each unit comes factory-equipped with cascadecontrol capability. Simple, quick access daisychain of up to 4 boilers, link to Raypak Temp TrackerMod+ Hybrid Master control for up to 16.

    3. Control Interface

    Large easy to read (3.5”) LCD display. Will continuouslymonitor flame strength (µa) sensor temps, BMSsignal (0-10V) set points, delta-T, all safety signals, fulldiagnostics and fault history for last 15 events.Simple touch pad settings. Everything you need fromset-up to service is at your fingertips, all in one location.

    4. Combustion Air Blower

    Cast-aluminum, non-sparking construction. The stateof-the-art variable-speed blower is controlled by the onboardVersa IC integrated controller and works in smoothharmony with the main gas valve.

    5. Dungs Gas Valve

    The XTherm uses a state-of-the-art main gas valvemanufactured in Germany. This precision gas valveworks in perfect unison with the combustion air blower.The result is silky smooth light-offs and a 7:1 turndown.

    7. Vent Pressure Switch

    Monitors vent pressure and provides safe shut down if back pressure is excessive.

    8. Gas Inlet

    The XTherm will operate at 100% full rate with gaspressures as low as 4.0” w.c.

    9. Water Outlet

    With PRV and T & P gauge installed.

    10. Boiler Pump

    Sometimes referred to as the primary pump. This pumpkeeps flow through the heat exchanger

     11. Water Inlet

    The XTherm can accept 50°F continuous inlet watertemperature and as low as 32°F during system startup.

    12. Cold Water Protection

    The XTherm comes factory equipped with a built-inCold Water Protection system. This advanced water controlsystem keeps the inlet water temperature to thenon-condensing heat exchanger above 120°F, regardlessof the incoming water temperature. It constantlyself-adjusts and regulates the incoming water flowwhile still maintaining a constant delta-T in the heatexchanger.

    13. Flue Outlet

    The stainless steel flue outlet is compatible with CAT IVstainless steel. PVC or CPVC vent material may be usedin conjunction with the D-32 vent option on theXTherm. Also available with option D-33 Polypropylenevent material. Dramatically cut your installation costs byusing these non-metallic vent materials.

    14. 316L Stainless Steel Condensing Heat Exchanger

    Recovers waste heat to boost efficiency into 96%+range. The XTherm utilizes a high-grade stainless steelheat exchanger. This allows the corrosive combustioncondensate to be collected safely without damagingthe heater. There is a condensate disposal connectionon the rear of the heater. The XTherm is also equippedwith a condensate switch that will sense a blockedcondensate drain, which protects the heater.

    15. Vertical Non-Condesing Heat Exchanger 
     Cylindrical, multi-pass heat exchanger captures allradiant energy, eliminating the need forheavy refractory.

    16. Drain Valve

    One of two drain valves located at the bottom of thenon-condensing heat exchanger. A third drain valve islocated on the condensing heat exchanger. This allowsfor complete winterizing and drainage of the heater.

    17. Viewing Port

    Allows for easy burner inspection.

    18. Weather-Proof Jacket

    Heavy gauge galvanized steel with a UV-resistantPolytuf powder coat finish is impervious to weatherand corrosion.

    Xtherm® Cold Water Protection System
    TheXTherm comes standard with a state-of-the-art Cold Water Protection Systemfactory-mounted and plumbed. Raypak's Cold Water Protection system providesconstant protection against condensation in the primary heat exchanger.The system utilizes one or two variable-speed pumps, depending on modelsize and type, to inject just the right amount of water from the mainsystem loop into the boiler to maintain the optimum inlet temperature.This allows the full capacity of the boiler to be utilized to meet thesystem load, while at the same time continuously maintaining the optimuminlet water temperature to prevent condensation in the primary heatexchanger. For models using the twin-pump design, each pump actsindependently giving the boiler up to a 10:1 flow turndown. All of thiskeeps the condensate where it belongs, in the stainless steel secondaryheat exchanger.

    Versa IC Boiler Control and On-Board Diagnostic Center

    The VERSA IC onboard control package merges safety, ignition and temperature control, outdoor reset and freeze protection, plus system monitoring, alarm and diagnostics,and BMS transmission all in one Integrated Control Platform. Easy front access to read, set up and trouble shoot on a 3.5” LCD screen. Theentire package is CSA certified, and listed for each individual function.

    Inlet and outlet sensors factory installed in boiler. Remote sensor for system included. BMS all point diagnostics transmission port. 0-10V DCset point input standard. Also can drive and monitor external motorized auxiliaries such as extractors and louvers. Additional connections forauxiliary functions such as indirect DHW, and dry contact remote alarm relay are provided.

    Safety Faults
    Condensate Drain
    Manual High Limit
    Auto High Limit
    Vent Pressure
    High Gas Pressure
    Low Gas Pressure
    Controller Alarm
    Flow Switch
    Blower Switch
    Factory Option
    External Interlock
    Cold Water Protection


    Ignition Control Faults
    Low Air
    Flame- No CFH
    Ignition Lockout
    Low Water Cut-off or Low HSI Current
    Low 24VAC
    Internal Control Fault


    Service Videos:

    XTherm® Basic Startup Video (EN)
    • XTherm® Vídeo Arranque Básico (SP)