Duo Therm AC freezing up

I would take another look when it is frozen. If the sensor is covered in ice that sensor or circuit needs fixed. If the ice accumulates in a place other than the sensor then move the sensor.

I wouldn't worry too much. Whenever you buy, it's going to have the new refrigerant. BTW, the residential and commercial trade name for this stuff is Puron.

Thanks for that info. Looks like I had better replace my home HVAC before I retire.LOL

Hondavalk wrote:

Bob Landry wrote:
You can check for proper charge on a R22 unit with a clamp-on ammeter, but most people don't know how to do it. The usual response on this forum for just about any air conditioner problem, and usually the incorrect one is low freon. Also, the non AC people won't realize that the newer units are charged with R410A, instead of R22. R410A runs at very high pressures and the high side pressure tends to be unstable and changes a lot with ambient temperature. That means you can't just have your local AC guy come out, sweat a service valve on, slap the gauges on it and charge it until the pressures "look" right. These units have to either have an exact charge weighed into them or they have to be charged by superheat, and they have to be charged as a liquid as opposed to R22 vapor charging.

R410A is a 50/50 blend of two different refrigerants. Since the two have different weights and molecular structure, a leak results in an imbalance because the two refrigerants leak at different rates. That blows your 50/50 mix.That means, if you actually do have a leak, the system must be evacuated, vacuumed, and recharged. These units are no longer shade tree repairable.

The OP says his TT is a 2005. Wasn't R22 units allowed until 2009?

I'm not sure when equipment production using R410A began, but the marine AC equipment that I sell and service has been using it for several years. It's just that the R22 stuff that's out there has been running for a long time and it's just within the past few months that I'm starting to have to deal with R410A. Even though there is no more R22 equipment being manufactured, the refrigerant is going to be available until 2020. There is no R22 now being manufactured and what we are getting is stuff that has been reclaimed, cleaned up, and recycled. In reality, it's a money grab. There are warehouses stacked to the ceiling with the stuff, but like everything else, someone figured out that there was money to be made with a created shortage. Also, available does not equate to affordable. As it gets closer to the cutoff the price of R22 is going to skyrocket just as it did with R12. I bought a 30lb bottle of R22 a couple of months back for $495. I bought a bottle of R410A yesterday for $88. Before it's over, there will be guys selling R22 from Mexico on the side of the road for $800-900 a bottle, and people will still be buying it. It just makes it tough on customers because I'm going to mark it up appropriately

Bob Landry wrote:
You can check for proper charge on a R22 unit with a clamp-on ammeter, but most people don't know how to do it. The usual response on this forum for just about any air conditioner problem, and usually the incorrect one is low freon. Also, the non AC people won't realize that the newer units are charged with R410A, instead of R22. R410A runs at very high pressures and the high side pressure tends to be unstable and changes a lot with ambient temperature. That means you can't just have your local AC guy come out, sweat a service valve on, slap the gauges on it and charge it until the pressures "look" right. These units have to either have an exact charge weighed into them or they have to be charged by superheat, and they have to be charged as a liquid as opposed to R22 vapor charging.

R410A is a 50/50 blend of two different refrigerants. Since the two have different weights and molecular structure, a leak results in an imbalance because the two refrigerants leak at different rates. That blows your 50/50 mix.That means, if you actually do have a leak, the system must be evacuated, vacuumed, and recharged. These units are no longer shade tree repairable.

The OP says his TT is a 2005. Wasn't R22 units allowed until 2009?

Hondavalk wrote:

dougrainer wrote:
1. They only have 1 lb of coolant, so if you had low coolant, the unit would be TOO LOW on coolant to cool . This is NOT your problem
2. IF you have a wall tstat, then your unit has a freeze sensor. If you have a freeze sensor, it CANNOT freeze unless the sensor is defective or is NOT installed in the evaporator coils.
3. IF you have manual roof top Controls, then freezing is a possibility, you need to run on HI Cool and make sure the Evap fins are clean and your Air filter/s are clean. Doug

Not meaning to argue but low refrigerant will cause freezing coils. AC works by absorbing heat. With low refrigerant ,which results in low pressure it can't absorb enough heat and the coils freeze

I should have explained fully. IF you have Low Coolant, that means you have a leak. IF you have a leak and only 16 oz of coolant, THAT coolant will be gone way before the unit can "freeze". Doug

Well I managed to get the cover off just before it got dark. The freeze sensor is poked through a little hole in some foil insulation or seal and into the coils where the link shows it should be. There didn't appear to be much in the way of dirt in there but I will take a shot at cleaning the unit this weekend. Did manage to evict a few families of hornets though so that was a good thing. :)

Clean the dirt and dust off the coils.
Make sure the freeze sensor is still in place on the coils.
During high humidity times run the fan on continuous and high.
The high fan helps to melt any frost or ice during the compressor off cycles.

You can check for proper charge on a R22 unit with a clamp-on ammeter, but most people don't know how to do it. The usual response on this forum for just about any air conditioner problem, and usually the incorrect one is low freon. Also, the non AC people won't realize that the newer units are charged with R410A, instead of R22. R410A runs at very high pressures and the high side pressure tends to be unstable and changes a lot with ambient temperature. That means you can't just have your local AC guy come out, sweat a service valve on, slap the gauges on it and charge it until the pressures "look" right. These units have to either have an exact charge weighed into them or they have to be charged by superheat, and they have to be charged as a liquid as opposed to R22 vapor charging.

R410A is a 50/50 blend of two different refrigerants. Since the two have different weights and molecular structure, a leak results in an imbalance because the two refrigerants leak at different rates. That blows your 50/50 mix.That means, if you actually do have a leak, the system must be evacuated, vacuumed, and recharged. These units are no longer shade tree repairable.

Hondavalk wrote:

dougrainer wrote:
1. They only have 1 lb of coolant, so if you had low coolant, the unit would be TOO LOW on coolant to cool . This is NOT your problem
2. IF you have a wall tstat, then your unit has a freeze sensor. If you have a freeze sensor, it CANNOT freeze unless the sensor is defective or is NOT installed in the evaporator coils.
3. IF you have manual roof top Controls, then freezing is a possibility, you need to run on HI Cool and make sure the Evap fins are clean and your Air filter/s are clean. Doug

Not meaning to argue but low refrigerant will cause freezing coils. AC works by absorbing heat. With low refrigerant ,which results in low pressure it can't absorb enough heat and the coils freeze

With 1 pound of refrigerant, any leak empties these units. Unless someone has broken the system, they are almost always either full or empty, except for the short time while they are leaking.
I'e never had one freeze up because of low refrigerant, and I've had many in because of freeze ups.
Doug is spot on, as usual.