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CH- Anti-Cycling on HTP

SuzookSuzook Member Posts: 215
edited November 15 in Gas Heating
Tryinng to cut down some of my cycling of my htp uft 80. I have adjusted my odr, to the best of my ability, i have it running almost constant, but still have some turn offs. There is an anti cycle setting. Im confused about it. Wouldnt turning it up to 30mins, means it runs 30 mins longer? Or should i turn it down closer to 1 min?

Edit, so i guess when set to 30, once fired, it will fire for 30 mins. I guess i need more adjusting of my ODR, and/or my combustion rate.

Comments

  • Leon82Leon82 Member Posts: 664
    With a 30 minute delay between firings you run the risk on not keeping up with the heat load. Depending on the amount of control options you may be able to limit the max fan speed or firing rate
  • SuzookSuzook Member Posts: 215
    Leon82 said:

    With a 30 minute delay between firings you run the risk on not keeping up with the heat load. Depending on the amount of control options you may be able to limit the max fan speed or firing rate

    Ok, so I'm understanding it wrong? It means it won't fire for 30 mins, as to what I was thinking as it would fire a minimum of 30 mins? So I guess I will actually just shut the anti cycle off.

  • fenkelfenkel Member Posts: 104
    You could turn down the  heat output btus.. see page 52 of install manual
    Has a heatloss calculation  been completed?
  • SuzookSuzook Member Posts: 215
    fenkel said:

    You could turn down the  heat output btus.. see page 52 of install manual
    Has a heatloss calculation  been completed?

    It's down to 70%, yes heatcalc was done. It runs almost constantly in the winter, but late fall and early spring lots of cycling. So I'm thinking odr needs adjustment. How do I get lower water temp, at higher outdoor temp? I get confused.
  • fenkelfenkel Member Posts: 104
     
    The only other question would be what is the design temp?
    The other possiblity would be to.change your outdoor reset setting for fall,winter and spring..
    But i think a buffer tank would make it a one time setup with no seasonal adjustments...
  • SuzookSuzook Member Posts: 215
    Here's another idea. I have 2 zones. My upstairs is always colder than downstairs, mainly because of insufficient slant fin at lower water temps I'm using. What if I combine the 2 zones, feeding upstairs 1st, thinking I could actually get better condensing this way too.
  • Leon82Leon82 Member Posts: 664
    Yes combining them may allow it to sustain the minimum rate for longer or eliminate cycling.
  • fenkelfenkel Member Posts: 104
    Might  need  a bigger zone pump.
    Gpms might be over 4. Head pressure could be high as well.. you might lose  a 20 degree delta, because of larger
    pump requirements .
    Does both zones run off one thermostate?
  • ZmanZman Member Posts: 6,123
    Outdoor reset will actually make short cycling worse. Less energy is being transferred so the boiler cycles on and off. This is better than overheating the space so ODR is still a good thing.

    I would experiment with the anti short cycling feature. A longer off time will equal a longer on time. The boiler will need to catch up.
    You could probably set it to 5-10 minutes with no side effects.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • SuzookSuzook Member Posts: 215
    Zman said:

    Outdoor reset will actually make short cycling worse. Less energy is being transferred so the boiler cycles on and off. This is better than overheating the space so ODR is still a good thing.

    I would experiment with the anti short cycling feature. A longer off time will equal a longer on time. The boiler will need to catch up.
    You could probably set it to 5-10 minutes with no side effects.

    Worse? This is the 1st time I have heard this. I'm actually thinking if I lower the min supply temp, that should make the boiler run longer at higher outdoor temps.
  • SuzookSuzook Member Posts: 215
    fenkel said:

    Might  need  a bigger zone pump.
    Gpms might be over 4. Head pressure could be high as well.. you might lose  a 20 degree delta, because of larger
    pump requirements .
    Does both zones run off one thermostate?

    I have a grundfos alpha. It's plenty big. 2 different thermostats. Are you suggesting higher speed on circ pump?
  • hot_rodhot_rod Member Posts: 14,075
    Suzook said:

    Tryinng to cut down some of my cycling of my htp uft 80. I have adjusted my odr, to the best of my ability, i have it running almost constant, but still have some turn offs. There is an anti cycle setting. Im confused about it. Wouldnt turning it up to 30mins, means it runs 30 mins longer? Or should i turn it down closer to 1 min?

    Edit, so i guess when set to 30, once fired, it will fire for 30 mins. I guess i need more adjusting of my ODR, and/or my combustion rate.

    You mention you have it running almost constantly??
    Use all the features the control offers, but on low load mild days there will always be some cycling, until we get boilers with 99-1 turndown :)

    A minimum 10 minute run time would be the goal and rule of thumb the industry uses.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • fenkelfenkel Member Posts: 104
    Does the upper floor zone run all the time?
    As far as speed is concerned, you need to determine the btus for the new zone. Then you'll need to determine the length of the conbine zone..
    Say your zone is 200 feet long..
    And your using 3/4 in copper pipe
    Copper 3/4 has a resistance of .04
    The formula is length of zone x 1.5 x pipe resistance 
    So..
    200x1.5x.04 equals a head pressure of 12 psi.
    Then take total zone btus and devide by 10000..
    This will give you gpms..
    Use this to see if your pump can handle it


    SuperTech
  • SuzookSuzook Member Posts: 215
    hot_rod said:

    Suzook said:

    Tryinng to cut down some of my cycling of my htp uft 80. I have adjusted my odr, to the best of my ability, i have it running almost constant, but still have some turn offs. There is an anti cycle setting. Im confused about it. Wouldnt turning it up to 30mins, means it runs 30 mins longer? Or should i turn it down closer to 1 min?

    Edit, so i guess when set to 30, once fired, it will fire for 30 mins. I guess i need more adjusting of my ODR, and/or my combustion rate.

    You mention you have it running almost constantly??
    Use all the features the control offers, but on low load mild days there will always be some cycling, until we get boilers with 99-1 turndown :)

    A minimum 10 minute run time would be the goal and rule of thumb the industry uses.

    Ok, so I will leave well enough alone. Thanks!
  • SuzookSuzook Member Posts: 215
    So i figured out an issue i was having with my upsatirs zone, not maintaining temp, and short cycling. I have a honeywell T-stat, and it was set for 5 cycles per hr. Meaning it would cycle it on and off 5 times per hour!. Changed it to 1, and walla. Temp is maintained, along with very little boiler cycling.
    SuperTech
  • PC7060PC7060 Member Posts: 72
    Nice!
  • SuzookSuzook Member Posts: 215
    You would think ALL tstats would have a proper setting for newer ModCons. They don't. My local gas company offering a free Honeywell touchscreen smart tstat. It has NO options for temp variances, or cycle per hour. Makes no sense.
  • BillyOBillyO Member Posts: 224
    Yes, free thermostat and access to your heating system. go buy it yourself

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