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New replacement boiler short cycling

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bengle
bengle Member Posts: 3
in Strictly Steam
our company replaced a existing steam boiler with a new H.B.Smith same rating as oil boiler.The problem is the boiler is short cycling on pressure switch.set at 16 oz vapor differential of 4. the risers are 2 full size pipes from boiler tapings to existing 4 inch manifold.returns have a hoffman receiver vent and a hoffman return trap. there are check valves in the returns. There is no hartford loop or condensate pump.

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  • KC_Jones
    KC_Jones Member Posts: 5,739
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    Did you do a full EDR calculation to size the boiler properly?
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • bengle
    bengle Member Posts: 3
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    yes
  • KC_Jones
    KC_Jones Member Posts: 5,739
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    When does it start short cycling? As soon as it starts making steam? Once the mains are full? At some other point? What size boiler? What is the connected EDR? Little more information would help. There are many people on here with way more knowledge than I with respect to the Hoffman systems. I am only responding to get more information for others to comment on.

    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
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    Have you checked all the radiator, and crossover traps for function? The air has to be let out somehow, and in the hoffman system there is their special air vent through which the air passes from the crossover traps. It looks like a ham, and was designed to prevent being waterlogged if the pressure rose too high. It also had a check valve on it maintain a vacuum, once the system was up and running.
    There is a wealth of information on these systems in the library here, and you could compare the piping you have with their required layout. These are wonderful systems which were very sophisticated for their day (early 1900's), and capable of heating with 2 ounces or even at sub atmospheric vacuum pressures.--NBC
  • bengle
    bengle Member Posts: 3
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    we do have some rads that i ordered repair kits for.this is a very large house with lots of rads there is about 4 that we are going to repace traps. i have replaced the air vent on the cross over trap. the boiler is 441,000 btu
  • Abracadabra
    Abracadabra Member Posts: 1,948
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    bengle said:

    yes

    What's the attached EDR vs. the boiler EDR?

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