Technicians who work on central air conditioners and heat pumps use manifold gauges to find the Freon pressure and indirectly the evaporator and condenser temperatures by connecting to access fittings on the unit. These gauges have hoses of various lengths and when they are removed from the access fittings some Freon is retained in the hoses. This is not a problem with systems that contain pounds of Freon since the amount retained in the gauge manifold hoses is a small percentage of the correct charge.
Household refrigerators and freezers usually do not have access fittings. This is not necessarily a bad thing. Some refrigerators work with as little as eight ounces of R-134. Connecting gauge manifold hoses to the high-side of the system could leave a large percentage of the charge in the hose when it is disconnected. To connect to the system and read Freon pressure one must use a piercing-valve, which clamps on the refrigerant tubing and punctures a hole to allow pressure readings. These valves must be left in place afterwards and provide a place for refrigerant to leak if they are not clamped tightly or if the seals deteriorate over time.
I only install piercing-valves on a refrigerator or freezer as a last resort. Despite the common belief that almost every refrigerator problem is due to the lack of Freon that is just not the case. Most refrigerator malfunctions are caused by the failure of electrical components. An insufficient Freon charge is one of the last things I consider when troubleshooting a refrigerator that does not cool. FREON LEAKS OUT; IT DOES NOT WEAR OUT. It is unlikely that your refrigerator will suddenly start leaking just sitting in your kitchen UNLESS it is manual defrost and you recently removed the ice from the freezer compartment by using a knife, screwdriver, chisel, or pry bar and punctured the aluminum evaporator coil or an incompetent service person installed piercing-valves that are leaking.
Conditions which may seem like lack of Freon but are not:
Evaporator fan not running which ices up the evaporator and raises freezer and fresh-food compartment temperature.
Condenser fan not running which raises temperature of freezer and fresh food compartment.
Dirty condenser which raises temperature of freezer and fresh food compartment.
Defrost problems (if automatic defrost) which ices up evaporator raising temperature in freezer and fresh food compartment.
Old compressor with worn valves that raises evaporator pressure and temperature.
Worn door seals that allow hot air to leak into the freezer or fresh food compartment (Note: Some Haier refrigerator doors won’t seal even when new.)
Clogged filter dryer or capillary tube which keeps the Freon from circulating properly.
All the above conditions make the compressor run continuously or almost continuously, but so does a lack of Freon. The compressor runs continuously because the refrigerator cannot reach the set-point on the cold-control. Keep in mind that if you set your cold control to mid-range and it can’t cool to that setting, turning it to max (which asks it to make the temperature even colder) does absolutely nothing.
The fastest and easiest way to find out if the unit has Freon is to turn it off and listen. When a compressor pumps Freon the evaporator pressure decreases and the condenser pressure increases (thus we have a high and low side of the system). When the compressor stops running the refrigerant pressures in the system slowly equalizes through the capillary tube. This can take several minutes. Turn the cold control to the off position and put your ear to the side of the unit. If you hear hissing and gurgling noises the unit has some Freon, which is equalizing through the capillary tube (it may not be a correct charge). If you hear nothing, the unit contains little or no Freon or has a clogged filter-dryer or cap tube OR the compressor is running but not pumping (worn or broken valve). None of these conditions are as likely as having a defective fan, dirty condenser, or defrost problem.
If you hear the hissing and gurgling of Freon, but the unit won’t freeze ice or the ice cream is soft, unplug the refrigerator and remove the cover from the evaporator. The evaporator is in the freezer compartment near the evaporator fan. Each model is different so spend a few minutes to figure out how to expose the evaporator. Some GE and Magic Chef models place the evaporator in the bottom of the freezer compartment which makes repairing the defrost system difficult. On an upright freezer the evaporator may be tubes that are part of the shelves so nothing needs to be removed. Chest freezers have the evaporator beneath the inner lining and usually cannot be exposed.
If you remove the panel covering the evaporator and find a big block of ice, you either have a defrost problem or the evaporator fan wasn’t running. Sometimes a defrost problem will form so much ice that the fan can’t run. Thaw the evaporator and see if the fan will run before condemning it.
If the evaporator is not encased in ice arrange the cover so that the unit can be restarted. This may be difficult if the fan is attached to the panel. The capillary tube is a small copper tube entering the evaporator. The suction line at the evaporator outlet will be much bigger.
Liquid refrigerant (freon) entering the evaporator begins to boil into a gas because of the sudden drop in pressure created by the compressor. This change of state absorbs heat. The temperature inside the evaporator coil may be -20 degrees F. This will condense and freeze moisture in the air in contact with the coil (which is why we have to defrost). If there is freon boiling inside the evaporator this frosting will occur within minutes. So if we run the unit with the cover off the evaporator and no frost forms we can know that there really is no freon or the the system is clogged. If the unit runs for several minutes with the door closed and the freon charge is correct, the frosting should form all along the length of the evaporator.
Other signs of the presence of freon is heat in the condenser. If the unit has been running for several minutes and the condenser is cold, there is either little or no freon or the system is clogged or the compressor is not pumping.
Another technique I have used is to feel the line on the high side. It should be so hot as to be uncomfortable to touch. This sometimes helps as looking at the evaporator takes more time to get to it, but it also is more accurate in determining if the charge is sufficient.
Good read
This is really great information. I do have a problem with the fridge since I decided to defrost it. If there is a puncture in the evaporator coil, is it possible to repair it? DIY?
better to buy a new one
in the business of selling them?
hi,im n pookwane,the seems to be no where i can learn the refrigeration cource.i the anything you can do for me pleae.i want ton know this!
Recently have bee smelling strong gaseous odor near fridge area. Burns eyes and smells like nail polish remover. Could it be freon leaking from refridgerator?
Freon has a slight odor, but it does not smell like nail polish remover. Refrigerators contain less then a pound of freon, most less than a half-pound. It isn’t likely that an odor would be detected unless the full charge vented.
Thanks for all your great info. I have determined that the refrigerant is low in my under counter fridge, and not one of the other problems. I have all the manifolds and piercing valves. My question is, is it best to add refrigerant to the high side or the low side? (On a car it is the low side, but that’s a different set of operating conditions.) Sorry if you have covered this elsewhere.
Charge on the low side with compressor running with the refrigerant container upright to prevent liquid refrigerant from entering compressor.
my GE monogram has ice on the coils — does that indicate low freon like an air conditioner?
No, frost is normal.
We moved here 17 months ago & took our fridge with us. It was working fine till about 4 months ago. Then I started getting water in the bottom of my fridge under the two veggie drawers & inside of them ruining my veggies ! I also noticed there was ice built up in the freezer. It’s self defrosting. Also got water on top of other foods on the shelves. Now it just doesn’t seem to get cold enough. I defrosted the whole thing 2 wks. ago real good. We even took the bottom thing out of the freezer. There was ice built up under it, too. I make my owm ice cubes with trays. Did it last night, & it’s still not completely frozen. Is it out of freon? And it still leaks water in there. Had to put a meatloaf pan on the bottom shelf to catch most of the water.
Thank you
Mary Sanchez
I would check that the drain line from the evaporator drain pan is not plugged. Water produced during the defrost cycle could be dripping into the refrigerator section rather than draining. A plugged drain line will also cause ice to freeze in the bottom of the freezer section. Another cause of water collecting in the refrigerator section is bad door seals.
this is a great site. We just returned home from out of town. while we were gone it was a record breaking 111 degrees. I noticed the freezer food was all defrosted and wet but the freezer was still a little cold and the fridge was just barely chilled. It keeps making a sound like it is struggling to get to the reached coldness like every 2 min. Is this a condenser problem or freon? condensers are pretty expensive right? This is a Amana stainless steel fridge on top and freezer on bottom.
I would first check the compressor and compressor starting circuit, then cold control, and defrost problems before considering freon and sealed-system components.
I recently did a compressor swap in a chance that I might save my old fridge. I’m not sure how much pressure should be on the low side when it’s running. I did notice that the evaporator is only frosting up about 1/4 of the evaporator coils. the low side pressure is running at 30psig. does this mean I need slightly more freon? and the system is using r22 freon
Our freezer quit working on our 12 year old side by side. It remains cold but won’t freeze. We called a serviceman who opened the doors asked how old it was and decided the compressor was out. He didn’t fix them himself but said it was old and we would be better off buying a new refrigerator. He did suggest a store that had a great deal going on new models.
Is it possible to run R22 in a Kitchenaid built in designed to run with R134A?
No.
I brought home a GE side-by-side refrigerator that had been abandoned by the previous tenants of an apartment. I plugged it up and waited a while and noticed it wasn’t cooling. After running it a few hours, it still wasn’t cooling. Before I was going to get rid of it, I installed a self-piercing valve on the low pressure line and added a can of freon. It started cooling after that and is making ice cubes. The only thing now is that the low pressure line and the side of the compressor is covered in a layer of thick frost. Does this indicate too much freon or could it need more?
Most likely caused by too much freon.
Yesterday afternoon, I noticed the food in my freezer was all defrosted and the temperature in refrigerator was 60 degrees. So I immediately,
set the temperature controls for the freezer and refrigerator for the coldest setting. This morning I noticed the temperature in the refrigerator is now 42 degrees and the freezer is starting to freeze the food. Should I wait and see if the refrigerator begins to keep cold again for a few days…or should I call a repairman anyway to have it checked? Also what would have caused the refrigerator and freezer to loose it’s coldness in the first place as I have had the refrigerator setting at a medium setting for years and never a problem.
I would look for defrost problems or evaporator fan problems although there are the strange ones like the interior light staying on from a bad switch.
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my refrigerator is a forst unit the old type one without the inner fan or defrost or heater or such things which are prensent in the no frost units, so my question if someone would like to answer me so i have a sealed evaporator and an outer condensor i’h checked out there is no refrigerant present in the system by removing the charging valve cap afer that i have given and air pressure of 150psi from my homemade compressor to confirm if my consealed evaporator got leakage, it drops down afer one hour so i would like to ask you people is anyother way to comfirm that conslead evapotor leakage,some scanner type equiments or some laser type if you would like to help me out so please tell me
thank you
what can you do if a fridge has been turned on its side and stopped working when uprighted again.
normally if you leave it upright for 24 hours to allow the oil to drain back into the compressor, the compressor will start with no problem. if not, there might be other issues than being on its side
I have a stand up freezer. I just defrosted it because there was a lot of frost build up on the second shelf but all other shelves are warm. The evaporator coli is integral with the shelving, I plugged it back in and it it has been about 30 minutes and only the same location where the frost had built up is getting cold enough to freeze the moisture in the space of the freezer. The rest of the coil is warm or should I say not cold enough to freeze the residual moisture left over from the defrost I just did.The section that is freezing had a small tube coming out the end which appears to go back to the compressor. I think this portion is at the end of the line but not sure. Do I have the situation where the R134A has leaked. I have one spot near the compressor which is underneath he freezer where there was some green powder residue collected on the tube. This looks like to location where the compressor was soddered to the coil. This is not in the freezer compartment but next to the compressor underneath the freezer. Is this an indication of where maybe the R134A has leaked? Perhaps I have a totally different problem. We bought the freezer new 10 years ago. Should I just go buy a new one?.
From your description, I would suspect a lack of freon (leak), partially clogged cap tube, or worn compressor valves. A check of freon pressure is probably the only way to provide further insight into the cause. I hope this helps. The green residue at the brazed joints was likely caused by brazing flux not being cleaned after brazing. It should have no impact on the units operation.
I have an old fridge, believe it’s a hotpoint, but not 100% sure. Anyways I have turned it into a kegerator, installed casters on it, custom paint job, two tap handles in the door. Everything is ready to go, accept when I plugged it in, it freezes everything no matter what setting I put it on. Someone suggested that it was low on freon, but from what I am reading that would make it not cold enough. Any suggestions on what I should check? The door seal is worn, but I dont think it’s that bad, kind of at a loss here
yes, someone always thinks refrigeration problems are freon related. Low freon would make the unit run constantly and not cool properly. If it is freezing everything, that isn’t the problem. Does it run constantly? I would be looking at the cold-control to see if it was defective and not cycling the compressor on and off at the set point.