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overpumped?

RLuck
RLuck Member Posts: 24
in THE MAIN WALL
Twin boilers piped primary secondary with teckmar 261. The boilers cycle on limit but the supply temp is only reaching 160 ish per the control sensor on the supply. The system was fine until we reached the design temp, low single digits. This is an old drafty church that has probably been worked on by many a handyman in its long life. I sized it with a 0014 taco using there charts and a little fudge factor. My guess is that the water is racing right by the boilers, also all three can vents are alowing water to escape and I believe one of the reliefs have let go. There is a main 11/4 loop with commercial baseboard and 3 3/4 inch loop. Does downsizing the pump sound like the best option or a good place to start? I followed the manufacturers specs for the near boiler piping. Also can you control the time frame for the second boiler stage or are you limited to the program options only?

Comments

  • SWEI
    SWEI Member Posts: 7,356
    What is the returning water temp? I'd start with that and a radiation survey. Your "little fudge factor" almost certainly had several fudge factors ahead of it that you weren't informed of.
  • Zman
    Zman Member Posts: 7,611
    What type of radiation?
    Big cast iron?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Paul48
    Paul48 Member Posts: 4,469
    We just saw a Viessmann that only produces 160 max. Just a thought.
  • RLuck
    RLuck Member Posts: 24
    Tube and fin baseboard. I did my best to follow the taco worksheet but some things I had to take an educated guess on. I had it narrowed down to two pumps but the taco description said "high volume" for the 0014, I guess we have different ideas of what that means. The 2 boilers are cast iron direct vents (budget and redundancy), they cycle on their own 180 limit but the supply temp for the system is only reaching 160 when the tekmar is looking for 180 to meet the demand. Essentially trapping the extra heat needed for the unusually cold weather in the boilers. I think the return temp is the best way to go, then I can swap out the 0014 for an 007 to confirm my findings.
  • SWEI
    SWEI Member Posts: 7,356
    RLuck said:

    I had it narrowed down to two pumps but the taco description said "high volume" for the 0014, I guess we have different ideas of what that means.

    A 0014 is lot of pump. I'm assuming it's the system pump? How many feet of baseboard, and is it in series? What kind of pumps are on the boilers, and how many BTU's are they?
  • hot_rod
    hot_rod Member Posts: 24,106
    what do you have for expansion? if the relief valve is going off you may have a waterlogged tank, or one that is undersized. sounds like a lot of water volume in that system?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream

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