American Standard Boiler (G-606) Pressure Control

JJJJJ

American Standard G-606 Boiler Pressure Control?

How do I determine what the pressure cut-in and cut-out's are for this boiler? How are the settings changed? The outside of the boiler has an Internal Syphon Compound gauge manufactured by Marsh Instrument Co. The gauge ranges from 30 vacuum to 30 pressure. It is wired to a small American Standard box (pressuretrol, I believe) inside the outer jacket of the boiler. It is summer now in Pittsburgh, so the boiler has not fired recently. The gauge now reads 8.5 on the vacuum side.

Here is some background information about the heating system:

The house is approximately 75 year old house with the following American Standard Gas Boiler (Series 2B-J3; Boiler G-606), installed in 1967. The house has a two pipe steam heating system. It has three types of radiators: plain pattern cast iron (U.S. Radiator Corp.), concealed radiators (McQuay Radiator Corp. probably), and two Base Ray's. Each radiator has a Thermostatic Radiator Trap (C.A Dunham Co. No. 1A) and a Dunham Packless Radiator Valve. The house also has two steam mains with a Dunham 1E trap installed near the end of each main. The dry returns connect the wet return through an Air Eliminator (Dunham Type No. 220).

I assume it is a vapor system, since there is no vacuum pump apparent, and a gravity system, because condensate doesn't appear to return by any mechanical means.