very old boiler, pressure relief releasing water.

Likely the original boiler (1926, "The Capitol" size: 25-5), originally on coal, then oil, now running on natural gas, in Chicago, brick 2 story, 2 apt building. About five years ago the expansion tank developed a leak, so I replaced it with an ETX 15 diaphragm expansion tank. After seeing the pressure relief valve releasing small amounts of water constantly during heating season for years, I took it upon myself to lower the reducing valve pressure, eventually to turning it out 2.5 turns. Since then no problem with releasing water, and the system, as far as I know, has worked fine.

This fall I noticed that the Bell and Gossett Series 100 circulator pump bearing housing had water in it. I replaced it end of oct. After that I get a short squeak from housing when pump shuts off. And, pressure relief was dripping for weeks. I tried opening it numerous times thinking maybe rust got stuck in when I turned water back on and flushed pipes through the pressure relief valve. Not getting it to stop, and not knowing if it or the reducing valve failed in the process of turning water off and on, I have replaced both the reducing and pressure relief valves. For about a week after that, water continued to dribble out of pressure relief, so I continued to open it to release move water, hoping to clear it. Water no longer continually dribbles from the pressure relief, but it does release water when heat comes on. maybe 1.5 gal over the course of a day.

I tried unscrewing the reducing valve adjustment 1 turn. I have also removed the expansion tank and checked its pressure. 8# the gauge said. I put a pump to it and increased it to 11# and reinstalled it. Pressure relief still releases water. The boiler pressure gauge, after heat being off for 4 hrs shows 12#.

Question is: shall I continue to lower the reducing valve pressure, maybe another 2.5 turns, so it is similar to previous one? Increase expansion tank pressure? Is the current recommendation of 12# pressure not applicable to older systems because maybe the pipes are larger or burners different or ....? Anything bad about having a lower pressure in the system? (With the lower pressure of previous reducing valve, I could still get water (bleed) all the radiators on both floors.)

bonus question: Some sources have suggested that the short squeaking noise at motor shutoff (not all the time) is caused by failing motor mounts. this squeak wasn't happening previous to bearing housing replacement. Local B&G sales reps said if the mounts were bad the coupler would be breaking. That the noise is likely coming from a not quite properly formed sleeve bearing. It may go away, Or I can get used to it. Or replace it under the one year warranty. What do you think about the squeak noise?