Gas furnace changed air filter found leak on exhaust pipe at the outlet. There's a leak coming from gasket connecting exhaust removal system to outlet pipe for exhaust. Voltage enhancement factory specs 7.5uf actual 4.89 uf. System is has error code 3 pressure switch open with inducer on recommend replacing switch and control circuit board. Blower is clean heat transfer media coil is good heat rise 51 Condenser voltage enhancement system factory specs 70/10uf actual is 62/8uf recommend replacing below allowable specs, voltage gateway is pitted condenser coil is dirty. Checked all hanging heaters all heaters are normal operation at this time. Cleaned boiler replaced filter and gaskets, replaced nozzle 2.00X70B, replaced screen and gasket inspected combustion chamber. Cleaned chamber sight glass is dirty can't see water level clear inspected flue checked low water cut,-off checked gapping of electrodes bleed and started system. System is functioning at this time