Ultra 399 - 317,000 BTU Output High Efficiency Boiler (Nat Gas or LP) Zoom

Ultra 399 - 317,000 BTU Output High Efficiency Boiler (Nat Gas or LP)


Brand: Weil Mclain

Weil Mclain
383-500-706 has been discontinued.
Direct Replacement:
SKU: 383-500-726
Brand: Weil Mclain



Fuel Type: Natural Gas
System Type: Hydronic (Water)
Features: EI/Spark Ignition
Direct Vent
Vent Size: 4"
Water Connection: 1-1/4"
Gas Connection: 3/4"
BTU Input: 399000
BTU Output: 317000
Warranty: Limited 15 Year Warranty on Heat Exchanger/ 1-year on parts
Width (Inches): 22-13/16"
Vent Type: Direct Vent
Boiler Type: High Efficiency

Description for Weil Mclain 383-500-706

**Series 3 Ultra Boiler
Key Features
- Gas fired water boiler with cast aluminum heat exchanger
- Venturi mixing body mixes air and gas providing higher efficiency
- Designed to operate in low temperature condensing applications
- Outdoor reset and domestic hot water priority standard
- Negative regulated gas valve precisely delivers gas to the boiler
- Electronic control module automatically adjusts blower speed and gas flow rate in response to environment
- Modulates with 5 to 1 turndown ratio
- Variable speed motor matches combustion output to heating needs
- High grade stainless steel burner features quiet operation, high efficiency, and cleaner combustion for low NOx applications.

  • Propane Conversion Orifice included for LP Gas Applications

    PLEASE NOTE: The product weighs 297 lbs. and may require the use of a
    lift gate.
    If you do require a lift gate at your delivery, you'll have the option to add this FREE of charge when you checkout.
  • Ultra 399 - 317,000 BTU Output High Efficiency Boiler (Nat Gas or LP)


    by PowerReviews
    Weil MclainUltra 399 - 317,000 BTU Output High Efficiency Boiler (Nat Gas or LP)

    (based on 1 review)

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    Reviewed by 1 customer

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    Make sure you get an extended warranty

    By bradshsi

    from Seneca Falls, NY

    Verified Reviewer

    Comments about Ultra 399 - 317,000 BTU Output High Efficiency Boiler (Nat Gas or LP):

    I got the Ultra 310 Series 3 installed in late 2008. The latest models (Series 3-UE) have slightly different heating outputs but the design appears to be nearly identical so consider that when reading what follows.

    I was lucky enough that Weil McLain offered a 5 year extended warranty free if you sent in the paperwork. Thank the stars I did because in the last 4 years I've had the control module replaced twice, the burner fan motor replaced once and numerous callouts to troubleshoot the boiler.

    Basically they failed to engineer and manufacture the control system/module properly. As a result it had programming bugs that caused the boiler to do quirky things or fault out. Nobody believed me when I described what the boiler was doing so in the end I had to video it and put the video on YouTube.

    After that they replaced the control module for one with updated programming. Unfortunately it had a different bug so after demonstrating the bug, we were onto our 3rd control module which thankfully seems to be ok.

    The burner fan motor failed this winter and luckily the $900+ part was covered under the warranty. I don't view 4 years as an acceptable life for a part like this.

    So you have been warned. Make sure you are covered warranty wise.

    What makes it such a shame is the boiler is quiet, efficient and other than the reliability I'm very satisfied with the performance.

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