Old Coal Fired Steam Boiler

[Neal Lewis]

In the attached pic of an old, coal fired steam boiler, there's a weighted lever type device at the top. The purpose seems to be to automatically or manually release steam pressure from the boiler. I assume with coal fired equipment, it was difficult to control the temperature inside. Hence the need to literally blow off steam once in a while. Am I correct?

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[Inspectorjoe]

It's a damper regulator. As the steam pressure increases, it closes a damper to slow the rate of combustion.

Was that thing still functional?

[Tom Raymond]

That is a beautiful machine from a simpler age. I'd keep it around even if it didn't work.

[Bill Kibbel]

When the steam pressure rises to a set pressure, a diaphragm lifts the arm of the damper regulator, slacking the chain on the other end, allowing the draft damper to close.

I can't tell from the picture, but there should be a rod on the other end of the arm that simultaneously opens the "check draft" damper on the flue connector.