Central A/C for home

[Woody]

I'm hoping that I can get some advice for my central A/C unit in my home. I've climbed up in the attic and removed the side cover for the coils, it's clean and clear, my filter is in the ceiling and was clean, but I replaced anyway. The outside coils have been cleaned ad have good flow through the coils. After the unit has been on for about 30 min. it ices up from inside coils down to the outside coils. The outside coils don't ice but the line leading from there to inside coils do. The inside coils ice over so bad the fan can't push air through coils, I have to shut unit down and set fan on manual to defrost coils. Is there a relay or switch that may have expired, or has my pump failed...? 

At a loss...

Thanks,

Woody

[ECtoFix]

3 hours ago, Woody said:

I've climbed up in the attic and removed the side cover for the coils, it's clean and clear, my filter is in the ceiling and was clean, but I replaced anyway.

That’s good.  Airflow is key.  Just be sure you’re using a standard pleated air filter, which should be replaced monthly.   Some of those fancy & expensive “micron” filters will affect proper air flow and shouldn't be used unless prescribe by the manufacturer.

3 hours ago, Woody said:

The outside coils have been cleaned ad have good flow through the coils.

The outside coils eject heat brought from the conditioned space (your house). That coil should be HOT (above 90°F-ish).

FYI: If airflow through the outside coils get restricted (clogged), this will NOT cause a freeze-up, but will INDEED affect overall system performance.

3 hours ago, Woody said:

After the unit has been on for about 30 min. it ices up from inside coils down to the outside coils. The outside coils don't ice but the line leading from there to inside coils do.

The outside coils won’t ice up, but the low pressure suction line to the compressor might ice up if the indoor coil isn’t absorbing the heat load as it should.

3 hours ago, Woody said:

The inside coils ice over so bad the fan can't push air through coils, I have to shut unit down and set fan on manual to defrost coils.

The question here would be whether the inside coil has enough airflow across it.  You said it’s clean, and the filter is NEW…so you’ve done all that’s expected by a prudent homeowner.

3 hours ago, Woody said:

Is there a relay or switch that may have expired, or has my pump failed...? 

By saying the pump, you mean the compressor.  A faulty compressor does NOT cause a freeze-up.  Actually, it would do the opposite by NOT cooling down to the temperature expected in a properly functioning system.

 Also, no relays or switches will cause that either…unless somehow one of them is diminishing proper fan motor speed (airflow)....which CAN cause a freeze-up.

*     *     *     *     *     *     *     *     *     *     *     *     *     *     *     *     *     *     *     *

Air-conditioners freeze up for one of three reasons:

• Low indoor airflow, which can be caused by several things (some of which you'd addressed)

• A low refrigerant charge - due to a leak somewhere in the system

• A refrigerant restriction, which can be several places within the system

You've done everything expected as a homeowner.  It's time to call a HVAC company to address your issue.

 

[Woody]

Thank you for responding...! Out of all of your advise, the one thing that stands out for me, is that I've been using a higher grade intake filter. A Honeywell #7, not the top of the line#9, not the bottom#4. I'll try running it with no filter and see if I have the issue, then if it persists, like you said HVAC call time.

Thank You Again!!

[Woody]

Had to make the call for help....

[HVAC_Jimbo]

Low on charge, TXV issue possible. Unless your a HVAC Tech make the call.