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Navien boiler

LonLon Member Posts: 2
I have a Navien CH-240 NG combo boiler.  The trouble I am having to every time we get the slightest bit of snow on the outside air intake plastic pipe the sensor in the boiler senses that there is a obstruction and automatically shuts the boiler down.  This has happened serveral times and now we are afraid to leave our house overnight..  The boiler is only a year old and my local installer has no answers for me.  Please help.


  • SWEISWEI Member Posts: 7,356
    Post a picture

    of the air intake & exhaust piping from outside.  How high is the intake?  Where are you located?
  • LonLon Member Posts: 2
    pictures of intake and exhaust pipes

    I have attached a couple of pictures of the intake and the exhaust pipes of my Navien CH-240 combo boiler.

    The intake pipe is on the right and the exhaust is on the left.  It is approximately 14 inches from the bottom of the intake pipe to the ground and about 22 inches from the bottom of the exhaust pipe to the ground.  They both has covers with slotted holes in them.

    If you will note the intake pipe is curved toward the house with a 45 degree elbow.  We did this because it kept getting plugged with snow when it went straight down..

    I live in northern Minnesota.

    Thanks for your comments.

  • SWEISWEI Member Posts: 7,356
    edited December 2013
    Intake is almost certainly too low

    Average snow height in January in Duluth (I took a guess) is 18."  Not sure what your local code requires but I'd suggest the lowest point on the intake be at least 12" higher.

    It's probably too close to the exhaust as well -- I'm not familiar with the Navien installation requirements, but every other mod/con I've seen requires more than you have.
  • TonySTonyS Member Posts: 849
    edited December 2013
    Navien would like to see the horizontal

    penetrations 12 inches apart and then a 90 turned down on the air and terminating 12 away 41 CH-ASME Installation Manual_201

    That being said, unless your getting big snows that are blocking the vent, I doubt that is your problem.

    If you open the front of your ch you will see a removable screen on the air supply pipe. Take a look at it and make sure its not blocked.

    The Navien air pipe is open to the boiler enclosure, it is not directly connected to the blower assembly. It uses the enclosure as a plenum. This type of setup makes the system much less sensitive to pressure imbalances.

    If you are having error codes thrown without snows literally blocking the vent I would look a little deeper elsewhere.

    One other thing I would like to point out, if you are using the Navien CH on a high temp system like baseboard or radiators you must use cpvc schedule 80 or PP venting. Looking at your pics, you have neither.
  • Mark EathertonMark Eatherton Member Posts: 5,582
    edited December 2013
    Gas meter...

    Here in Colorado, the appliances air intake must be at least 10' away from the gas meters pressure regulator vent…

    And although it would be a definite uglification, you could/should consider snorkeling both pipes upward to get it clear of the snow line. I don't know Naviens installation standards, but pretty much all other manufacturers I've dealt with require the terminations be 12" above the highest average potential snow depth. That installation would not cut it in Denver.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • icesailoricesailor Member Posts: 7,265
    Not like that:

    That is absolutely NOT the way to do it.

    On the venting alone, it is wrong and too low to the ground. Every manufacturer and their installation venting manual that I have seen says a minimum of .3 Meters or 12" above the ground or snow load. Massachusetts requires that you use this web site to determine what the AVERAGE snowfall in the city/town you live in. It is the average of the highest reported storms in a month. Usually January. In Duluth, MN, it is 18". Therefore, the vent terminations MUST be at least 30" above the bare ground.

    Go to this site and scroll WAY DOWN to the weather statistics. Look for "snowfall". January is 18". On average, you can expect a 18" snowfall in Duluth Minnesota in January. Go to and fill in your location.

    If it isn't vented to those spec's, and someone gets hurt, your ass will be grass and the lawyers will be playing lawnmower.
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