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I installed a Navien unit recently for a customer and they are having trouble

Upstairs is about 120 square feet on its own zone, and has no problem. Domestic hot water is no problem. Downstairs about 780 square feet with two bedrooms a large open concept living room kitchen and a bathroom. That is on its own zone as well. That downstairs wont get above 68 degrees on a 30 degree day. This house was a Sandy rehab and the boiler wasn't operating when I got there. You can see that all the house was redone downstairs and there is new baseboard wall to wall throughout the downstairs. The bathroom is the only unit that is the old style radiator. I have bled the system and raised the heat output for the boiler to 180 degrees already. Still the unit cannot overcome the cold. Only downstairs. I have the return temp coming back at 148 or so. They just added insulation in the floor which there was none in the crawl space. They also added pipe insulation down there. I dont know what else to recommend or how I should go about handling this.

Comments

  • GordyGordy Member Posts: 9,530
    edited December 2014
    Im confused the unit was there when you got there, but you installed it?? Was it there in a box?
    What model?
  • pacman45pacman45 Member Posts: 8
    No I installed and supplied the new unit. There was an old gas fired boiler that was not working. The owners did not want me to look at it but just replace it with a newer boiler. They had new tenants coming in to rent the place. They wanted a more efficient unit and I have installed about ten of these with no problems or complaints and they didn't mind my price. I used a CH_210 Combi unit
  • pacman45pacman45 Member Posts: 8
    I will measure the baseboard length tomorrow. We are using 007 taco units. I did take everything for granted when I did the unit. I just used similar equipment to that was there. Would a condescending type boiler not act the same as a standard as far as heating the baseboard? They had 007 units before. I am just wondering why it's not working like it would have before?
  • GordyGordy Member Posts: 9,530
    edited December 2014
    That combi on board pump only delivers about 4.0 gpm for 40k output 20 delta. Is it piped p/s? Secondary pump? Pressure drop of base board loop? Flow requirements of baseboard? I would think 40k would cover 1000 SF.
  • pacman45pacman45 Member Posts: 8
    What is p/s piping?
  • pacman45pacman45 Member Posts: 8
    This is the first time I am having a problem and have installed 9 or 10 of these units in the past. I use the recommended manifold and pipe in my zones using circulators on the heat side and have my dhw on the other side with a cold feed and then the water feeder direct to its location for automatic filling. I don't know any other way to pipe them?
  • pacman45pacman45 Member Posts: 8
    I don't know if maybe I need a larger circulator or something but the system seems to be working just not good enough. How much baseboard would I need to warm up a 25 by 20 room with 9 foot ceilings and standard insulation? What would be the way to calculate it? Formula? I am sure they knocked down walls and just ran baseboard without any calculations and hope it works. The piping of the baseboard in the crawl space goes in a hundred directions
  • pacman45pacman45 Member Posts: 8
    Yes when using their manifold that is already set up from them to run my zones.
  • IronmanIronman Member Posts: 6,176
    pacman45 said:

    What is p/s piping?

    If you used the optional manifold, then it provides p/s piping.

    Can you post some pics of the near boiler piping?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • pacman45pacman45 Member Posts: 8
    I will tom when I get there. Thanks again for your feedback and help.

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