Staem Boiler

Joe P_2

I have a Weil McLain steam boiler that runs perfectly until the house is 80% warm. It then shuts off and constantly tries to reignite but will only run for 30 seconds at most. At the time of this shut down the thermostat is not yet at temperature, the new pressure gauge reads 1 pound and the water sight glass is in the perfect range. The pressuretrol pigtail is positioned front to back and the pigtail has been cleaned. To make matters worse at least once a week it runs perfectly and warms the home until the thermostat is satisfied. Where do we go from here?

Fred Harwood

Bad vibes

or bad wiring. Sounds like (but could be something else) a loose wire at the thermostat or elsewhere. Check all wiring.

Thad English

vents

Is this one pipe or 2-pipe steam?

Make sure that your main vents are working. A bad vent can cause the short cycling you are describing.

Are your steam mains insulated?

[Deleted User]

Check the stat

heat anticipator. Should match or have a higher setting than relay or gas valve requirement. If electronic, set to lowest cycle number.

Boilerpro_3

That's exactly where I would look

For steam I set to the highest setting and then work down, if necessary.
Boilerpro