My central unit is running (both the outside compressor unit and the inside air handler unit), but the cool air isn't reaching the air ducts (even with filter removed from the system and no apparent blockage to prevent air flow). In fact it seems the air handler is blowing the air the opposite way (forcing up towards the return ducts) because cool air is escaping from around the seals of where the return joins the blower unit as if blocked... didn't think this was possible. Any ideas? Thanks...
Hi, sorry you're having a/c trouble.
I'm Tom and I'll do my best to help.
It's possible if the cooling coil in the furnace plenum is iced up.
Do you see any ice or frost on the insulated refrigeration line by the furnace?
Any water dripping around the outside of the furnace?
No reply...opting out.
All work to be done by licensed professional. WE KEEP GOING UNTIL YOU HAVE THE INFORMATION YOU NEED, I come and go. This is step ONE.
Hello, Tom was on the right track. It does indeed sound like your cooling coil is iced up... it can take as much as 6 to 8 hours to melt the ice with the thermostat set to FAN ON, and the cooling set to OFF, and the unit outside not running to melt the ice.
it can be a 50 pound block of ice in some cases.
Watch it closely the front cover removed from the furnace to insure no water from the melting ice gets on the electronic controls.
The most common causes of icing are one or a combination of the following:
- dirty air filter
- air ducts a bit too small or air supply registers turned off or blocked.
- running the AC all night set below 72F when its not hot outside.
- On older units, dirt clogging the cooling coil and fan blades.
- A little bit low on refrigerant.
Look all that over, let me know what you think, we can go from there until the situation resolves.
Retired HVAC/ Electrical & Boiler contractor. Industrial