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setting differential on 2 stage gas boiler

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Empire_2
Empire_2 Member Posts: 2,340
in THE MAIN WALL
What I gave you was an example. If you could give the #'s I could actually see exactly what you have and go from there. You read me right, but it all depends on how the control is set up. Basically I would want lo fire to run from 180*, it's cut out and stay engaged all the way down to 165*. Any further drop with exception of that additional 5* to 160 would kick in the hi fire side of the system. See what kind of info. you can get. A picture would also be great.

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  • Dave_61
    Dave_61 Member Posts: 316
    setting differential on gas boiler

    Our gas boiler has 2 stage burner with operating control set at 180 and high fire control set at 160.
    Behind each of these knobs is an sdjustable differential that allows adjustment of the +/- differential for each burner.
    Currently, both are set at 11 degrees. What would be a good setting for these?
    We have hydroair fan coils as our emitters.
    Thanks.
    Dave
  • Empire_2
    Empire_2 Member Posts: 2,340
    Here is what I would do

    180*-15*diff lo fire/ basically firing on lo fire with a stable return temp of 15* to 20* where it should be. If the load is to much or colder days arrive, Hi fire would be at 160* with a diff of 5*. Exmp. boiler fires on lo fire and is keeping up and cycling. Return temps are between 160 and 165. When larger demand occures or out door temp drops, Hi fire will kick in when it sees a drop to 155* and remain on until it can get back up to 160*. This is 160-5*diff. for hi fire. Since on lo fire you are maintaining a 15 to 20 Delta T, that is great. I would only want hi fire when the temps get cold or you are in a cold start situation. Give it a try, Mike T.
  • Dave_61
    Dave_61 Member Posts: 316
    Mike,

    > 180*-15*diff lo fire/ basically firing on lo

    > fire with a stable return temp of 15* to 20*

    > where it should be. If the load is to much or

    > colder days arrive, Hi fire would be at 160* with

    > a diff of 5*. Exmp. boiler fires on lo fire and

    > is keeping up and cycling. Return temps are

    > between 160 and 165. When larger demand occures

    > or out door temp drops, Hi fire will kick in when

    > it sees a drop to 155* and remain on until it can

    > get back up to 160*. This is 160-5*diff. for hi

    > fire. Since on lo fire you are maintaining a 15

    > to 20 Delta T, that is great. I would only want

    > hi fire when the temps get cold or you are in a

    > cold start situation. Give it a try, Mike T.



  • Dave_61
    Dave_61 Member Posts: 316
    Mike,

    Let me see if I've got this right.
    I will set low fire at 180 with a differential of -15 and set high fire to 160 with a differential of -5.
    I haven't looked closely at the dials, but there is a - as well as a + setting to the differential? Or do I just turn the one on the low fire for example to 15?
    In other words, does it also go in the other direction...so if the setting is 180 with a diff of 15, would that mean that it comes on at 165 and shuts off at 195 (or does it still shut off at 180?
    BTW, it's a Lochinvar EBN 300.
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