gas furnace

Any thoughts on residential combinations natural gas boilers for hydronic and domestic hot water? Would you put one in or go with two independent systems? Thank you in advance for your feedback.

I have a high efficiency downdraft gas furnace. When the unit runs a for a longer time due to the cold weather, water comes out of the bottom of the unit (A coil area). The entire area and next room carpet ar getting wet, The blowers on the unit are working and no error code coming for th unit...