Most boilers tolerate up to 50psi operating pressures, but it's ridiculous to run the thing at 27psi cold 37psi hot, unless the top radiator is 4-5 stories above the boiler. Many/most are shipped with 30psi pressure relief valves unless a higher pressure version is requested.
Auto-fill valves cause as many problems as they solve, and a non-adjustable one is even worse. Shut off the fill-water to the boiler ahead of the auto-fill, and bleed the system down to where it's ~12psi when cold, then see where the operating pressure ends up. Odds are good it'll be sub-20psi, depending on the expansion tank, it's pre-charge, and the system volume.
If the boiler has an embedded tankless coil for hot water or an indirect tank and there is a tiny leak between potable and heating side, that's a common cause for pressure-creep on the heating system. If the fill valve is hard-off and you bleed the system down to 12psi, keep an eye on it- you may have other issues to attend to.