How Can B-Y Help? Have B-Y contact you I Have Frost On My Suction Line! Though refrigeration and A/C share the same basic cycle and many of the same components they also have many differences. Frost is a big difference. Normally an A/C coil temperature stays above freezing. Frost on an A/C coil tells you there is a problem but not so in refrigeration. A refrigeration coil is normally operating at a SST of 25 degrees or less so it won’t just sweat but frost. The fin spacing is much larger on a refrigeration coil to allow for proper air flow thru the coil even if it has frost on it. As the coil builds frost some type of a defrost cycle is needed. On a walk-in cooler especially with an outdoor condensing unit it is a good idea to install a defrost timer to cycle the refrigeration off 2- 4 times a day to allow accumulated frost to melt. The evaporator fans continue to run circulating air across the coil melting the frost. On a freezer, defrost heaters may be added to melt the ice during a defrost cycle.

When heaters are used the fans will shut off during the defrost cycle. Many indoor condensing units run on a low pressure control instead of a thermostat. Adjusted properly the low pressure control will not allow the compressor to turn back on until the coil has warmed up enough to ensure that the frost is gone from the coil. Frost may also indicate a problem in the refrigeration system. When the coil only frosts on the inlet a starveling evaporator is indicated. air conditioning units for small spacesLow charge, restriction or a TXV that’s out of adjustment are some common causes. home ac unit won't coolI have frost on my suction line! different types of ac unitsThis may indicate a flooded evaporator. A flooding evaporator is being fed more refrigerant than it can’t all boil off and this may slug the compressor.

Liquid leaving the evaporator may be indicated by frost on the suction line or compressor. A flooding evaporator may be caused by low load on the evaporator (fans off) or a TXV that’s out of adjustment. Frosting evenly across the evaporator is what should happen on a properly feeding coil. Check the coil superheat at the evaporator outlet. Normally the superheat should be between 8 and 12 degrees. Too high and the coil is starving. Too low and the coil may be overfed. Proper superheat will indicate the problem is elsewhere. Frost on the suction line or on the compressor may not be a problem at all! On freezers the coil temperature could be -10 or even lower. With 10 degrees of superheat the suction line would be 0 degrees. 0 degree suction gas may cause part of the compressor to frost as well. As long as we have proper or any superheat, even with a frosted compressor there is no liquid getting to the compressor. In this case the frosted suction line and even compressor are ok! Leaking door gaskets especially inside a building that has high humidity may increase the rate at which frost builds up on a coil.

Replacing worn none sealing door gaskets will help keep frost accumulation to a minimum. Bad door gaskets may also prevent the cooler or freezer from holding proper temperature. With this ductless ac troubleshooting guide, you can find problems with your system, fix it yourself, and save a lot of money.We will guide you through the process of identifying the problem and repairing your air conditioner or heat pump.The normal service charge would cost you over $100 but, with this guide, you can save that money. **NOTE** Only you can assess your ability to perform these actions. This is a guide and cannot give the details/procedures for every possible situation. If your unit is not operating, you should begin your ductless ac troubleshooting by checking the display on the fan coil for a fault code. In most units, the display will show an E with a number. With that number you can narrow down the problem by referring to the user manual/installation instructions.Next, you should check the room temperature setting.

On most units this is done with the remote control. Ensure that the unit is in the proper mode and the setpoint is correct. You should also make sure the unit has been off for at least three minutes. If the display on the air handler is blank, check the fuse or breaker for the unit. In the case of a tripped breaker, you should check the wiring connections in the outside unit. Some units also have a fuse on the control board in the air handler. Continue your ductless ac troubleshooting by checking the air filter. It should be washed at least every month. Also check to see if there is any ice buildup on the coil. If there is ice build up, check to make sure the fan is working. Make sure the blower wheel is free to move. If it is free and the fan is not working then the problem is probably the motor or the control board. If the fan is working, allow the ice to melt and check the refrigerant level in the unit. If there is no ice and the fan is working, you should go to the outdoor unit.

If the fan on the outside unit is not running, you should check the dual run capacitor. Our capacitor testing guide will help you with that. If the capacitor can is bulging, it is a good indication that it is bad. If the capacitor is good the condenser fan motor may be bad. You can use our fan replacement guide to help you.If the fan is running, feel the compressor to see if it is running. If it is hot to the touch and not running, shut off the power and cool the compressor by pouring water over it. Then, check the outdoor coil and make sure it is clean. You should also check the dual run capacitor.After the unit is running, you should check the refrigerant level.If, after the compressor is cooled down, the unit makes a loud humming noise when it is trying to start, the compressor rotor may be stuck. You can use a hard start capacitor to try to get it to run. If the compressor still does not start, it may need to be replaced. You can use our compressor testing guide to check to be sure.

If the fan and compressor are running but the cooling or heating is insufficient, start by cleaning the unit. Ensure the fan coil, filter, and condenser coil are clean. Then you can check the refrigerant level and adjust per the operating instructions.**NOTE** IN SOME COUNTRIES, YOU MUST BE CERTIFIED BY THE GOVERNMENT TO HANDLE REFRIGERANT. If the unit's refrigerant charge is adequate, the unit may be improperly sized. The only way to tell if the unit is the proper size is through a process called a load calculation. If your unit is dripping water, you should begin your ductless ac troubleshooting by checking the drain hose to see if it is clogged. The easiest way to do this is with a bottle of water. Outside, stick the end of the hose in a bottle of water. Seal around the bottle opening with your hand. Then squeeze the water bottle and then pull the hose out. The water should drain but this may need to be done a few times to make sure the line is clean.If the hose was not clogged, check to make sure the fan coil unit is sloped properly.