1940 FLATTOP CAPILLARY R152A CONVERSION
Sept 7, 2020 16:05:48 GMT
ckfan, icebox, and 1 more like this
Post by don on Sept 7, 2020 16:05:48 GMT
General Electric owned the Hotpoint refrigerator line and with variations used the GE refrigeration components in the their manufacture. I had a 1940 Hotpoint flattop that i decided to convert to a R152A capillary system. I had previously converted a 1938 flattop so I knew what I was getting into. This thread should be more to the point. Instead of the static condenser attached to the back of the cabinet the 1940 Hotpoint uses an air cooled condenser located in front of the SO2 compressor in the bottom compartment.
monitortop.freeforums.net/thread/1650/successful-capillary-conversion-using-r152a
The 1938 machine I earlier converted gave me huge problems when I evacuated it as I am sure it had pentane added to it at the factory to aid in oil return. I did not have that issue with the evacuation of this machine. I chose a day when the wind was blowing in the proper direction away from my garden and lawn as SO2 will kill plants. I released the charge slowly from the access valve on the float and from an added tap I added to the low side. I then used an air powered venturi vacuum and evacuated it to about 25 inches vacuum. Because ny air compressor is not large I had to do this in intervals and wait for the air compressor to catch up. In order not to exceed the duty cycle of my air compressor and burn the motor I often isolated the refrigerator with the valves and walked away and let the air compressor motor cool down. This would not be necessary with a large compressor/tank combination.
I then finished the evacuation to 30 inches with an electric pump. I brought the machine up to 0# psig with an environmentally friendly refrigerant and then ran the refrigerator for several minutes to release any entrained SO2 from the oil. I again pulled a 30 inch vacuum and repeated this sequence until I had no SO2 smell coming from the vacuum pump when I pulled it down to 30 inches the final time. I lost count but I did this over six times. I made sure to change the vacuum pump oil after the last general vacuum and again before the final vacuum.
I cut the inlet and outlet of the high side float and unsweated the low side copper tubing and reused the tubing. I unbolted and removed the evaporator to add a 1/4 OD copper extension to the inlet. I again used 120 inches of .031 ID capillary with a spun copper refrigerant filter drier. The machine had a nameplate that called for 28 oumces of SO2. I estimate that I used 20 ounces of R152A. I charged the machine watching the frost pattern and did this over a three day period.
It appears to be running as well as the original SO2 high side float system. I am a huge believer in crankase heaters and because this is used in my detached garage in Minnesota I had previously added a heater for when it used SO2 and will continue to use it on the R152A. I need to reinsulate the copper lines and will redo the wiring for easier access. I am considering adding a strong magnet to the bottom of the crankcase in the hopes that it can capture and hold any metallic powder or particles from circulating in the oil. Maybe that would help reduce the ohm readings to ground that some machines have.
drive.google.com/drive/folders/19x5wLydyBaGMenv0B6tl_28auIlQzB6-
monitortop.freeforums.net/thread/1650/successful-capillary-conversion-using-r152a
The 1938 machine I earlier converted gave me huge problems when I evacuated it as I am sure it had pentane added to it at the factory to aid in oil return. I did not have that issue with the evacuation of this machine. I chose a day when the wind was blowing in the proper direction away from my garden and lawn as SO2 will kill plants. I released the charge slowly from the access valve on the float and from an added tap I added to the low side. I then used an air powered venturi vacuum and evacuated it to about 25 inches vacuum. Because ny air compressor is not large I had to do this in intervals and wait for the air compressor to catch up. In order not to exceed the duty cycle of my air compressor and burn the motor I often isolated the refrigerator with the valves and walked away and let the air compressor motor cool down. This would not be necessary with a large compressor/tank combination.
I then finished the evacuation to 30 inches with an electric pump. I brought the machine up to 0# psig with an environmentally friendly refrigerant and then ran the refrigerator for several minutes to release any entrained SO2 from the oil. I again pulled a 30 inch vacuum and repeated this sequence until I had no SO2 smell coming from the vacuum pump when I pulled it down to 30 inches the final time. I lost count but I did this over six times. I made sure to change the vacuum pump oil after the last general vacuum and again before the final vacuum.
I cut the inlet and outlet of the high side float and unsweated the low side copper tubing and reused the tubing. I unbolted and removed the evaporator to add a 1/4 OD copper extension to the inlet. I again used 120 inches of .031 ID capillary with a spun copper refrigerant filter drier. The machine had a nameplate that called for 28 oumces of SO2. I estimate that I used 20 ounces of R152A. I charged the machine watching the frost pattern and did this over a three day period.
It appears to be running as well as the original SO2 high side float system. I am a huge believer in crankase heaters and because this is used in my detached garage in Minnesota I had previously added a heater for when it used SO2 and will continue to use it on the R152A. I need to reinsulate the copper lines and will redo the wiring for easier access. I am considering adding a strong magnet to the bottom of the crankcase in the hopes that it can capture and hold any metallic powder or particles from circulating in the oil. Maybe that would help reduce the ohm readings to ground that some machines have.
drive.google.com/drive/folders/19x5wLydyBaGMenv0B6tl_28auIlQzB6-
