AC Conundrum

[Fargus]

Last fall we had an issue with the copper lines on the exterior condenser freezing up. It was turning cooler and just left it be. Turned it on once over the winter just to check it out and it froze up pretty quickly.

Called a tech out today. Apparently there was air in the line and possibly some acid from a bad condenser fan. It appears that the tech who installed our new condenser 4yrs ago never evap'd the system and left air in the line. Don't know HVAC so I have no clue if a system could run 4yrs with air in the line. Just what the tech today told me.

The tech today verified there was plenty of refrigerant in the system. He also purged the air from the system. The air filters are new. The coils in the attic have been cleaned. After all that, the lines outside and the evap coils on the handler are still freezing up. After the freeze, the air handler fan cuts off.

The fan in on the handler turns freely by hand and there isn't any burnt smell. The capacitor on the handler fan was changed out today. The air handler is old and in need of replacement but want to understand what is going on.

[Kingfisher789]

They usually freeze up like that when it’s low on Freon....

[Kossetx]

Acid from a condenser fan? In your closed system? They're making up more new stuff than the kung flu folks. Call someone else.

[miket]

If it wasnt evacuated properly there is a chemical reaction that causes corrosion inside. They call it non-condensables. Basically water ( moisture ). To get it out you have to evac again and hold to make sure its out and then recharge with clean refrigerant. Non condesable.can cause freeze up because it can make the valve stick/malfunction that regulates refrigerant flow.

The fan cannot introduce noncondensables.

[double bogey]

There was an issue industry wide several years ago where an oil additive compressor manufacturers were using cause a situation where a reaction cause an expansion valve issue. Could have been that, but unlikely. There is also an issue with cap tube systems where high condenser temps cause the poe oil to breakdown and cause contaminants that clog up cappilary tubes, this is prevalent on small refrigeration systems, also unlikely to be your issue.

What you were seeing was your indoor coil was freezing, and the suction line outside had frost or ice, where the copper was visible.
Coil icing can be caused by several problems, none of them are bad condenser fan. Essentially the coil ices because its temperature gets below 32°F. This can be cause by: low (indoor) airflow, low refrigerant level, refrigerant restriction, txv malfunction, and several others.
Most of the time when a system has air from improper evacuation procedures, it operates with increased high side pressures due to the fact that at the refrigerant pressure and temps a/c's operate at air is not condensable. It ends up taking up volume inside the condenser, causing inefficient operation if there is a little, to not cooling at all if there is a lot. Most of the time with r410a, or r134a systems using poe oils, if you have moisture, it will end up in the compressor oil, and you cannot get it out by evacuation. The only way to remove the moisture is to change the oil. I am speaking of personal experience working on systems from 1/4 hp refrigeration, to 2000 ton centrifugal chillers. POE oil is very hygroscopic, it absorbs moisture, and will not let it go.

Your system didnt run for 4 years with non condensables in it and all of a sudden ice up because of it, or a failed condenser fan.
I can tell you 75% of the icing coils calls a tech makes are going to be cause by dirty filters. Or running with no filter and ending up with a dirty indoor coil. $$$$ to fix

disclaimer: if you have a heat pump, you are going to get frost and ice occasionally on the outdoor coil, this is by design, and there is a defrost cycle that occurs automatically to deal with it. If yours stays iced up, you need a service tech to look at it.

[RattlesnakeDan]

Have you cleaned your outside condenser. Mine was frosting up and blowing the high pressure switch. I sprayed my condenser out all 4 sides very good and all is fine.

[bowhntrmatt]

Call a better AC guy. Sounds like a bunch of nonsense. I would bet it is either low on refrigerant, has a metering issue, or an indoor airflow issue.

No way a condenser fan introduced acid into a system.
No way someone “purged” air from the line without completely evacuating, replacing filter-drier, and recharging the system.

You said the blower cuts off after the freeze-up. Any chance its cutting out before it freezes and actually causing the freeze-up?

[SFAbowhunter]

What others have said. Call another AC guy out.

[Fargus]

Call a better AC guy. Sounds like a bunch of nonsense. I would bet it is either low on refrigerant, has a metering issue, or an indoor airflow issue.

No way a condenser fan introduced acid into a system.
No way someone “purged” air from the line without completely evacuating, replacing filter-drier, and recharging the system.

You said the blower cuts off after the freeze-up. Any chance its cutting out before it freezes and actually causing the freeze-up?

No chance whatsoever. I was outside looking at the frozen line while the air handler fan was running.

[LWolken]

Call a better AC guy. Sounds like a bunch of nonsense. I would bet it is either low on refrigerant, has a metering issue, or an indoor airflow issue.

No way a condenser fan introduced acid into a system.
No way someone “purged” air from the line without completely evacuating, replacing filter-drier, and recharging the system.

You said the blower cuts off after the freeze-up. Any chance its cutting out before it freezes and actually causing the freeze-up?

This^^^

Nothing your guy said makes sense nor is it how you handle acid in a system.

[double bogey]

Blower probably doesn't cut off after freeze up. Iced coil doesn't let any air through it.

[bowhntrmatt]

Blower probably doesn't cut off after freeze up. Iced coil doesn't let any air through it.

I was just thinking this.