1994 Ford Tempo No heat

I would like to know your opinion on why I still have no heat. I removed the radiator and air conditioning condensor due to a very slight accident that damaged both the rad. And cond. While these were off the car I replaced the thermostat. I should tell you that the heat did not work prior to the accident. I removed the heater hoses and ran a garden hose to both pipes on the heater core and water ran freely in both directions. I then connected the hose to one of the heater hoses attatched to the engine to check the water valve for blockage. Water ran freely from the lower radiator hose. I reconnected to the other hose with the same result. I thought I would get water from one hose to the other but without the radiator connected I am guessing there just is not enough pressure. From here I removed the spark plugs and they all seem to appear the same in coloration. The oil was drained and there are no traces of water in the oil or any white residue under the cap. I am assuming the head gasket is intact. I pulled the control unit from the dash and inspected the control cable and it appears to be operational as do the switches. The cooling fan operates perfectly. After all of this I reinstalled the radiator and condensor. Refilled the system on a slope to avoid air entering as much as possible started the car and ran for half an hour and I still have no heat. I did not change the temp sending unit could this possibly be the culprit? The engine does not over heat. Any other ideas? The radiator and condensor were replaced prior to reinstalling.