I have an oil furnace that heats the house with water pipes, and heats the hot water used personally. There are two thermostats used, one for the house and second for the back porch. The issue is with the porch. The back thermostat was set at 45F to save fuel. But, the temperature is at 70F. The furnace comes on about every 20 minutes for roughly 3 to 4 minutes. The house does not warm up to this level as set at 45F too with a separate heat pump used to warm up air a few times a day. Today, I changed the back digital thermostat with a manual Honeywell CT87K, only a two wire hook up white and red. There has been no change, still getting 70F temp in porch. I checked the furnace, there is a tall copper pipe out of the top of furnace bent in a U dripping water out onto the concrete floor. Possible solutions? Did I screw up new thermostat? Why the porch not the main house having the same issue?