Help with A/C freezing up ..

[ford_truck_guy]

My brother in law swapped his 13.5 A/C last year for a brand new 15k A/C at a local RV repair. That place is now closed and he had an issue this past weekend..

We were camping in 90* weather Friday and Saturday with NO Issues... a front came through last night and took the humidity and heat away with temps in the 70*'s this AM.. He had cool air blowing, but it was not blowing hard... went up on the roof and his lines inside the shroud were all frozen...

He is 50 amp with 2 A/C's and was plugged into 30 amp service so was only using 1 AC..

Any ideas on what may be happening...

[time2roll]

Snomas wrote:
My front AC would freeze up if I had the temp set too low when it was 90* plus outside and if I had the temp set on 72-74 degrees. I was told by a HVAC repair man that I should run them at 78 or higher and they wouldn't freeze up. This was on my 02 Dutch Star with 2-13500 units. Later in life I changed them out to 15000 units and never had a freeze with temps set at 74 degrees and over 108 outside. My DW never wanted to use the DS in temps over 100 until I got the 15K units.
Not sure why this little TT I bought last year will do in hot climates w/ only one 13500 init

I suspect the 15k replacements were better installed. Maybe even had the freeze sensors in the right spot.

[poppa]

low voltage wont cause yur ac to freeze low airflow or low ambient with low set point will

[Snomas]

My front AC would freeze up if I had the temp set too low when it was 90* plus outside and if I had the temp set on 72-74 degrees. I was told by a HVAC repair man that I should run them at 78 or higher and they wouldn't freeze up. This was on my 02 Dutch Star with 2-13500 units. Later in life I changed them out to 15000 units and never had a freeze with temps set at 74 degrees and over 108 outside. My DW never wanted to use the DS in temps over 100 until I got the 15K units.
Not sure why this little TT I bought last year will do in hot climates w/ only one 13500 init

[spoon059]

Could be a variety of options. Best case scenario is that the fan was on low. It doesn't move enough air to keep up with the humidity, the excess humidity freezes on the coil. Our AC is always on high, I don't even know why low is an option.

In regards to voltage, I'm not sure what low voltage would do in terms of allowing the coil to freeze. Just because YOU had low voltage doesn't mean that he did. I stayed at a beautiful state park a couple years ago that had 7 sites per run of electric. I kept getting low voltage and my EMS would disconnect power, my FIL at site 22 next to us never had a blip on his power and ran fine all weekend. The park ranger told us to avoid sites 7, 14, 21, 28 and 35, because they all had voltage problems in the summer when everyone's campers were pulling lots of amps for AC.

This is the type of problem that you wouldn't know by simply checking the power upon arrival. We were among the first people to get there. Plugged in and immediately turned on AC with no problem. It wasn't until around noon the next day that everyone's ACs kicked on at the same time to cool down. Plenty of voltage at the start of the run, not enough at the end of the run.

[CavemanCharlie]

ford truck guy wrote:
My brother in law swapped his 13.5 A/C last year for a brand new 15k A/C at a local RV repair. That place is now closed and he had an issue this past weekend..

We were camping in 90* weather Friday and Saturday with NO Issues... a front came through last night and took the humidity and heat away with temps in the 70*'s this AM.. He had cool air blowing, but it was not blowing hard... went up on the roof and his lines inside the shroud were all frozen...

He is 50 amp with 2 A/C's and was plugged into 30 amp service so was only using 1 AC..

Any ideas on what may be happening...

If the change in air temperature and humidity were quick then it's possible that it just couldn't keep up with the sudden change. Don't worry about it unless it happens to often.

It's hard for these systems to change quickly. Give it a chance. It may never happen again. Or, it may happen only in a situation where temps change quickly.

Shut it off, let it defrost, and try it again.

[ford_truck_guy]

2chiefsRus wrote:

ford truck guy wrote:

bob213 wrote:
Fan not on high or auto? Freeze sensor dislodged from correct place?

Bro in law was not sure, sis in law THINKS it was on high, but not sure..

I will say this, I kept experiencing "LOW VOLTAGE" as my Progressive Industries shut me down 3 - 4 times due to low voltage... Could that have been the issue?

Does brother in law not have a Progressive unit to detect low voltage? Hope he didn't damage the air conditioner.

He does NOT have one....

[2chiefsRus]

ford truck guy wrote:

bob213 wrote:
Fan not on high or auto? Freeze sensor dislodged from correct place?

Bro in law was not sure, sis in law THINKS it was on high, but not sure..

I will say this, I kept experiencing "LOW VOLTAGE" as my Progressive Industries shut me down 3 - 4 times due to low voltage... Could that have been the issue?

Does brother in law not have a Progressive unit to detect low voltage? Hope he didn't damage the air conditioner.

[AJR]

The only time I had the main AC start to blow cool air slowly. I removed the filter. Took a flashlight and peered into this hole with a mess of wires in it. I could make out the surface of the cooling coils (if that is what they are called) covered with ice off to the side. Hum… I guess I need to run the fan only till the ice melts. I started to look at the connections I could see hoping to find something lose. Then I noticed a wire dangling that looked like a sensor.

After the ice melted I could see where the sensor must have been placed in the cooling fins. I picked a spot close to the original and pushed the sensor into the fins. Problem solved. I have always run the fan on high speed.

[prichardson]

What temperature did he have his thermostat set at? Trying to keep it too cold at lower ambient can lead to freeze up; however, the frost sensor (if there is one) should prevent it. Doubt if it low refrigerant as it is a new unit. Poor installation leading to re-circulation or restricted airflow could also be the problem.

[colliehauler]

theoldwizard1 wrote:
Freeze up is usually caused by low refrigerant.

This would be my guess as well.

[theoldwizard1]

Freeze up is usually caused by low refrigerant.

[time2roll]

Remove the lower trim and inspect the evaporator for ice. If it has a wall thermostat look for the freeze sensor and get it placed in the ice. Also check the plenum divider is placed correctly and sealed to properly separate the air-in vs air-out.

You can cycle it yourself to clear the ice by leaving fan on high and cycling the compressor off. Or alternate the air units every 30 to 60 minutes.

[ken56]

Worst case scenario is it has a refrigerant leak and it is low on refridgerant. These are sealed units and not serviceable. Best case is it's just the fan setting. The fan MUST be on high.

[ford_truck_guy]

bob213 wrote:
Fan not on high or auto? Freeze sensor dislodged from correct place?

Bro in law was not sure, sis in law THINKS it was on high, but not sure..

I will say this, I kept experiencing "LOW VOLTAGE" as my Progressive Industries shut me down 3 - 4 times due to low voltage... Could that have been the issue?