I'm having issues with my AC. Basically, the symptom is that I feel cold air coming out of the vent, but it has no pressure, almost like I have to put my hand IN THE VENT COVER to feel any cold air. To me, it seems like the blower is not blowing any air, or it's clogged somewhere in the process and it is blowing.
Just some background… I just moved into this house, so I don't know too much history of the AC here. We haven't really tried it yet because the weather just got hot.
It's a central unit with the compressor/condenser outside.
I found the filter inside was extremely dirty, probably due to all the remodeling we did here. I will replace that. (Note: as of this question writing, I have not tried the AC with a new filter yet).
My thermostat is new (On a side note in case of relevance, the previous thermostat did utilize the B wire. I did some research and this is a common wire, the new Honeywell thermostat does NOT have a slot for it, and the instructions state to tape it up and move it out of the way).
Continuing on in my troubleshooting, I have identified the Condenser coils are extremely dirty with weeds and grass. I have also identified the blower fan is full of dirt and dust.
I have a few questions which would really help me in continuing troubleshooting.
1) Can the condenser fins be washed with a garden hose after sprayed down with condenser cleaner? I have read different opinions online regarding this matter (I have seen some units where the fins/coils seem to come off the unit, and others where people spray the unit with them attached). I don't know what kind I have. It seems kind of sketch to wash the unit with a hose when there is electrical components inside. I'm a huge fan of the shop vac in case I can use that on the fins, as well.
2) Here is a picture of my blower fan. Can I take my shop vac/compressed air to this bad boy without damaging it? I don't know a lot about HVAC, brand new to all this. I am asking so I don't damage it further.
EDIT (Removed the pics to my dirty blower, thanks for the answer).
06/23 EDIT:
@Ryan Smith — I looked up the Model number I found on the evaporator box above the furnace.
While I didn't find an exact match, I found the newest models have only 4 screws holding the cover on.
Newest model:
http://www.adpnow.com/wp-content/themes/adp/flash/circles/hahe-2.jpg
Here is my setup:
https://www.dropbox.com/s/x6mg3q3sd9qiikn/Photo%20Jun%2023%2C%2011%2029%2016%20AM.jpg?dl=0
As you can see, I have some kind of tape covering my cover screws.
Looks like my top line can just pull out (Looks like a fit plug that pops out), and the bottom unscrewed… and I can check out how clean/dirty the evaporator coils are.
I don't know how (And don't have the tools) to do a test from the supply side, but I think there's still a benefit in being able to take this box off in that I can clean the coils off. Agreed?
Also, you told me to check out my ducting in the crawl space (I have a ranch style, so nothing HVAC in the attic) for leaks. I didn't even have to go that far. There's a hole in the duct right above the evaporator box. I posted a pic of it in a comment below.
Based on what I've seen so far, I'm not going to be surprised if the rest of the duct has holes all through-out… plus dirty evaporation coils.
Thanks for the help.
Best Answer
You had (maybe sub-optimal) working air, so the holes (unless new) are probably not the primary cause. I imagine your evaporator coil (the coil inside the interior air handling unit) has frozen over.
This typically happens when the airflow over it is restricted, but it can happen when the refrigerant has leaked out of the system. Air restriction prevents warm air from heating the coil, which will eventually freeze the humidity out of the air creating an insulating block of ice. Low refrigerant levels super cool the coil creating the same freezing over.
So, replace (or temporarily remove) the dirty air filter. Open all the vents. Turn your AC off for a long enough period of time to melt the ice (typically 4 to 5 hours, but sometimes less). Then turn the unit on. If airflow is restored, you know the symptom of your problem.
If you don't freeze up again, it was likely an airflow problem you just fixed with the new air filter and by opening the vents. Occasionally the interior fan is not turning on, so opening the interior unit is a good idea for visual inspection.
If air handling seems fine and it freezes up again, call a professional to find the leak in your system, have the leak repaired and then get your system recharged with refrigerant. Many pros like to charge the system and run; but, refrigerant doesn't degrade or get "used up". If you're low, there's a leak. Get them to find and fix it now or risk calls and extra strain on your system (which could shorten the life of your system).
Opening the unit involves removing the tape around the panel (it is typically metal duct work tape, so use gloves to avoid cutting your hands). The tape only seals the unit for air tightness. There are screws on the panel. When done, re-tape with metal tape for air tightness.
Keep in mind that the root cause is sometimes electrical. If so, you'll notice the interior fan not is not turning on. There are additional circuit breakers on the air handling unit, as well as the possibility of burnt out control circuitry, corroded / disconnected wiring, etc. It is a good idea to turn the breakers off and on just to assure it's not the cause.
I'd fix the duct work, but to save you money on your AC bill, it's not a likely root cause.