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Is my boiler cycling normal?

I recently had the pressuretrol die on my 70 year old boiler. The service man replaced the pigtail and pressuretrol. I set the cut in @ .5psi and the differential to about 1.5psi. I know that the less pressure the better with one-pipe steam. But now the thermostat calls for heat, the boiler runs for a while and then cuts out at high pressure, cuts on after pressure drops, repeats until the thermostat stops calling for heat. My question is: Is this normal? Is this effecient?


  • Al Letellier
    Al Letellier Member Posts: 781

    That's exactly the way it's supposed to work. Unless the cycling is very abrupt, it's the normal operation sequence. Your service man did it right by changing the pigtail to make sure there was no obstruction.

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  • Boilerpro_2
    Boilerpro_2 Member Posts: 89
    How long are the on and off cycles?

    Do you have any radiators shut off? You may have a boiler that is just too big for the job.

  • Peter mark
    Peter mark Member Posts: 7
    boiler oversized?

    Most boilers are oversized, aern't hey? But the pressure settings you report are too high ! Suggestion: Cut out setting 1 3/4 PSIG, cut in setting 1/2 PSIG.doing this on a standard pressuretrol however, you will need a diaphram type vaporstat............
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