The system was on and running when arrived. Checked the oil flow and transformer, both are ok. When the zones were calling for heat, the circulators were making a whooshing sound. Noticed the pressure gauge was reading 5 psi, lifted the handle on the automatic water feed and it added water to the system and stopped at 20 psi. With pressure in the system, the noise went away and temperature in the boiler started to drop. There was not enough water in the system to push the water to the 2nd floor. System is operating properly.