Cold air blowing out of the vents when the heat is on gas could be due to a few reasons. One common reason is that the furnace may need maintenance or repair, such as a clogged filter or a malfunctioning thermostat. Another possibility is that there may be a problem with the gas supply or ignition system. It is recommended to contact a professional HVAC technician to diagnose and fix the issue.
Replace Thermostat
55 degrees to 60 degrees
There is no heater matrix for the back air vents, only and evaporator for the A/C. My suburban always blowed cold until I added an extra rear heater matrix.
What do you mean by "has no heat"? No air blowing out, blowing out cold air when heater is on, blowing nothing at all? Heater not turning on? What specifically is happening?
looking for answer
what i am assuming is being talked about is that when you go to turn on the heat in a Seville, heat will only be produced out of one side of vents. there are a number of valves in a Seville which control wether the air that is coming out of the vents in hot or cold. in a Seville there are a pair of these valves one for the passenger side air, and one for the driver side air. the reason why only one side of the car is blowing hot air is because one of these valves has gotten stuck in the "cold air" position and needs to be replaced. the same thing happened on my car but the drivers side was the one not blowing heat.
Is it blowing cold air only or not blowing any air at all.
The coil is dirty.Hose it out with a water hose.
There are 2 filters you access in the glove box. If they are dirty you get almost no air. Clean or replace them and be amazed at the difference
There should be at least a 12 degree split between the incomming air and the air comming out of the vents.
A duct has come apart under the home?
Probably a bad thermostat.