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Steam Pressuretrol Setting

Matt_28 Member Posts: 34
I have read everywhere that I should only have .5 to 1 psi set on my pressuretrol for my 1 pipe steam system. I have a Honeywell Pressuretrol L404A (pdf attached) that states it has a psi range from 2 to 15. I am able to set my Main and Differential settings lower on the pressuretrol than the 2 mark, but the specifications seem to relay that it has a minimum of 2. The installer set it to 10 and 5 a year ago and I would like to change it to a practicle pressure. I have the following questions regarding this:

1. Does anyone know what my Main and Diff settings should be to get below 2 psi or suggest what I should set it at to get the least pressure allowable with this pressuretrol?

2. If below 2 is not possible, should I replace it, with what? It seem easy, but should I be replacing this myself?

3. With the setting at 2 psi will I be waisting the gas (gold) that I consistently pump into this newer system? We had monthly gas bill last year close to $700. This is a new Burnham Independence Boiler.

Finally, The system seems to be working very well with settings on the Main at roughly 1 and Diff at roughly .5. I say roughly because their are no marks below the 2 level. It is heating the radiators completely within 20 minutes. I have noticed rusty sediment around the ceiling and pipes near the main vents, but I think the installer never came back to remove the build up in the pipes once it was installed and I have drained the system since to remedy the issue, hopefully.

Thanks for any advice.


  • Al Letellier
    Al Letellier Member Posts: 781
    pressuretrol setting

    Matt, on the 404, turn the setting screw until the indicator bottoms out. Then set the differential at 1. That should do the trick. The high energy bill isn't all the boilers fault, it's the cost of the gas!!!!And it's relatively inefficient BTU content.

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  • Matt_28
    Matt_28 Member Posts: 34
    Steam Pressuretrol settings

    Al, I will change the setting tonight. I know it is the rising cost of gas that is behind all my pain. I am hoping to cut any cost from last year with these new settings and a cleaner system.
    Thanks for you help.
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