Hi

First time poster on the site. I'll cut right to the chase.

My condo was built in 2005. It was never lived in until 2013, when we bought it.

I wasn't great about changing the air filter - changed 5-6 times in 7 years. A couple days ago, we realized the AC was running 24 hours per day without cooling the house at all.

I watched some YouTube videos and asked a friend with some knowledge, and I was led to believe the evaporator coils were probably dirty.

It has taken me two days of painstaking step by step work, but I now have access to the Evaporator Coils (top side only). I can't figure out how to take off this Triangular Access Panel.



Some pictures are attached. Is the triangular metal attached to anything internally? It doesn't seem to want to come out. Could it be rusted in place? Or does the metal fold inside and attach elsewhere?

Step One: Notice the ice inside



Step two: I finally got the door out of the way, revealing evaporator coils (top side only)


I can't get the triangle out - it seems to be either rusted in at the bottom or otherwise attached internally.

Note - can that white drain pipe be unscrewed? i wonder if maybe it's blocked (although i poured some water in and it drains fine)


I shine my flashlight inside, and it doesn't seem particularly dirty (like i've seen in YouTube videos), leading me to wonder whether this is even the correct diagnosis after all?


Thanks in advance .

 

Even though it doesn't look visibly dirty, it has never been cleaned since I have lived here (2013) and probably never in life of unit (since construction in 2005). I was hoping to see it filthy though.

 

Another note - the other day when this started, I replaced the (very dirty)air filter. I turned the unit back on (not knowing at the time that it was full of ice). The problem remained (as well it should have, considering it was full of ice).

If I had let it simply defrost at that point, could it have worked? I wonder if the only problem all along has been the very dirty air filter and now I'm opening everything else up for nothing....

 

There are generally two causes for the evaporator freezing up: low air flow across the evaporator coil, or low refrigerant charge. If it feels like you're getting normal airflow (when the evaporator isn't iced up), then it's unlikely to be an airflow problem, indicating that your evaporator coil isn't excessively dirty. This would point to a low refrigerant charge (likely the cause).

If the airflow is low, even when the evaporator coil is not iced, then it is possible that your coil is extremely dirty, or there's something wrong with your blower (motor or squirrel cage).

 

My coil is over 25 years old and I've never seen it. It's never been cleaned.
I'd have to obliterate the duct work to get to it.

Coils do get dirty but the action of the condensation washing down them rinses them off. Since you have the side off your unit off ..... poor several cups of bleach down the drain line or as close as possible followed by some hot/warm water. That dust and algae build up to form a grunge that blocks the drain line.

 

Thanks Pete - I'll try that tomorrow.

 

Have you checked outside condenser ? Is the compressor Running ?

 

Hmm... Well the big fan does turn on. I'm not sure what else (or how) to actually check anything other than that.

 

You said it was frozen. I figured maybe the high pressure switch tripped but then the fan wouldn't run. Since your fan is running it's not a refrigerant pressure problem. That leaves a problem with the compressor.

To go further than that you are going to need a meter to dig into the unit.

 

Let it defrost and give it another try.

 

I poured the bleach and hot water in today, and then closed everything up. The temp has fallen by a few degrees in the house, but i must not have done a great job sealing up the evaporator coil housing (duct housing? not sure what it's called) -- its got cold air blasting out from a bunch of different nooks and crannies.... along seams etc

I'm not sure if those are new or they've always been there and i just never noticed.

The inside humidity has dropped from 60% to 55% pretty quickly (I had the unit completely off for a few days) ...
I'm going to use some HVAC tape over these holes.

I did peak a flashlight in one of the holes before taping it up and it seems the coils have a LIGHT coating of frost --- is that minimal amount of ice normal?

I'm going to turn the temp way down and see if the temp keeps dropping.

See the picture. That frost on the lines is after just 30 minutes or so....


If it's still a problem, i suppose i'll have to surrender and call in the Pros

 

Before taping the access door back in place. Let it run for a while..... maybe overnight. Check the coil again in the morning. If it's iced again.... you may be low on refrigerant.

A light even frost is somewhat normal. It depends on the humidity and the temperature of the incoming air.
What is most important is that the coil frosts evenly. That's not easy to see thru a little peep hole.

 

Hi, with the compressor running feel the the lines going into the house from the condenser, the big copper should be cold and maybe sweating, the small line should be hot. Make sure the evaporator coil is thawed out.
Geo

 

Turning the temperature setpoint way down isn’t going to make it cool faster or better. The thermostat isn’t a throttle. Even on a modulating system, which you don’t have there, it’s just telling the unit what temperature it needs to go to.
If your already developing frost I’d say you have a refrigerant charge issue.

 

I opened it back up - coils covered in ice.

Just to recap what i've done
1- cleared drain line with bleach & hot water
2 - visually inspected bottom sides of evaporator coils - couldn't really get in there with any spray due to access issues but they seemed clean
3 - changed air filter
4 - outside, cleaned out any debris out of the compressor unit and did the best i could cleaning the coils (there's no hose)

Regardless, after a day of use you can see the photos below. This leaves me feeling it must be the refrigerant, and I'll have to call a service tech Monday.

I should note - i did feel cold air blowing out in the vents around the house but i felt it was running for longer than it should to get the desired temperature reduction....

 

There is two things that can cause that..... low on charge and low airflow.
Did you have a good airflow from the registers ?
If yes..... looks like your next step is to have the charge checked.

 

Hmm...good question. I'd have to answer that honestly it wasn't super strong . I opened all vents. Could I try taking out air filter altogether and see if maybe it's too restrictive ? It's a MERV 10. That's likely not the issue though - it's brand new

 

Hi, you have totally defrosted the coil ,correct? remove the air filter and set the fan to RUN on the Tstat, no cooling, now what does the air flow feel like?
Merv 10 maybe a bit restrictive.
Geo

 

Thanks Geochurchi

I let everythign defrost over night. I turned it on this morning with only the FAN (no A/C).
It did seem a little better - fairly strong -- but I may be mentally comparing that to yesterday (when the system was blocked up with ice).
Regardless, I have some other stuff to return to Home Depot so I'm headed there shortly. I'm going to buy some MERV 7 or 8s and throw them in and give it another go.

Once it's running, I'll also verify the proper temps on the lines as you indicated earlier.

On another note, I do hear some hissing and gurgling from the AC unit when it's running. Could be another sign of a Refrigerant leak. But at least I'll have ruled everything else out first.