Fedders split system hp 5ton 10 seer.liquid icing with low suction line pressure in cooling mode .system is not low on freon

Hi,
The unit has a leak and is low on freon...
Here is a tip about troubleshooting your air conditioner...
There are many things that can cause your air conditioner not to cool...

AirConditioner Trouble - Review the Possibilities

heatman101

Below is a guide to troubleshoot and check system function. This can be done by most folks.

Look at the front of the ac compressor and have someone turn on the ac from inside the car. The front of the pulley(clutch) will spin when turned on.

If it does not spin, the low pressure switch (LPS) is not satisfied. Meaning there is not enough freon in the system to operate the system. Means low freon capicity because of a leak.

The LPS can be jumpered to cause the compressor to run (clutch to engaged) which will draw the freon in the system.

The LPS is usually a two wire sensor on the suction of the compressor. (between evaporator and compressor) Unplug the sensor and install a jumper, this will engage the clutch. Connect a new can of freon
and fill to system capacity.

The capacity of the ac system will be on a label under the hood, do not overfill. Probably about 2 lbs. Local parts stores (Auto Zone and Advance) will have freon with stop leak. This may help the leak. They also make a freon with a UV dye. I always add a single can with dye so that if stop leak does not work I can find the leak in the future.

The system should be filled until suction pressure is about 30 to 38 psi..

Remember the flow for the a/c system is :
1. From the compressor a high pressure (HP) gas goes to the condenser in front of the radiator.
2. From the condenser a HP liquid goes to an expansion device (orifice tube or expansion valve)
3. From expansion device the low pressure gas enters the firewall to the evaporator.
4. From evaporator the low pressure liquid/gas mixture goes through the dryer back to the compressor suction.

Below is a guide to troubleshoot and check system function. This can be done by most folks.

Look at the front of the ac compressor and have someone turn on the ac from inside the car. The front of the pulley(clutch) will spin when turned on.

If it does not spin, the low pressure switch (LPS) is not satisfied. Meaning there is not enough freon in the system to operate the system. Means low freon capicity because of a leak.

The LPS can be jumpered to cause the compressor to run (clutch to engaged) which will draw the freon in the system.

The LPS is usually a two wire sensor on the suction of the compressor. (between evaporator and compressor) Unplug the sensor and install a jumper, this will engage the clutch. Connect a new can of freon
and fill to system capacity.

The capacity of the ac system will be on a label under the hood, do not overfill. Probably about 2 lbs. Local parts stores (Auto Zone and Advance) will have freon with stop leak. This may help the leak. They also make a freon with a UV dye. I always add a single can with dye so that if stop leak does not work I can find the leak in the future.

The system should be filled until suction pressure is about 30 to 38 psi..

Remember the flow for the a/c system is :
1. From the compressor a high pressure (HP) gas goes to the condenser in front of the radiator.
2. From the condenser a HP liquid goes to an expansion device (orifice tube or expansion valve)
3. From expansion device the low pressure gas enters the firewall to the evaporator.
4. From evaporator the low pressure liquid/gas mixture goes through the dryer back to the compressor suction.

Hi, It is not uncommon for the suction line on a unit to have ice on it when cooling. This means that where the ice starts forming on the line, there is liquid freon there. But, if it continues to get worse, would indicate a problem as you don't want liquid freon to enter the compressor as it will burn out the valves, or slug it as we say. Icing of this line can be from a few things. Low on freon will cause it to ice up. The freezer fan/evaporator fan motor not working. The freezer iced over real bad. An over charged system will do this, but you haven't had to charge it. Check the fan I mentioned and keep an eye on this line and monitor the units temperature. If you start to loose your cooling then we need to go from there. I can't prevent it from forming ice unless I was on site to install my service gauges to check the internal condition. Please keep me posted though. If the freezer fan is not running, this would be the problem and would need to be replaced. If you had excess to a volt meter and it wasn't running, you could check power to this motor. Let me know if it is not running and check the temperatures closely.
Good Luck,
Shastalaker7

You are still low on freon. Charging AC by superheat and subcool
First charging a unit by superheat, this is only for Acs with an orifice or capillary tube.
Optimum superheat is 12° to 15° at the compressor or suction line outside the unit.
Hook up your gages and put a thermometer on suction line (large line), start the AC. Measure the temperature of the suction line and read the pressure on your gages. Theres a temperature scale on your gages for R-22 or R-410A the needle will show you the pressure on the outer scale and if you follow it down to the R-22 or R-410a inner scale that is the saturation temperature for that refrigerant, (you can also use a temperature pressure chart), now read the thermometer, let’s say the suction temperature( the thermometer) is 67° and the saturation temperature (the gages or temp. press. Chart), is 55°, subtract the saturation temperature from the suction temperature, 67°- 55° = 12° superheat.
Charging by Subcooling, this is for Acs with a thermostatic expansion valve, it’s common to see a sight glass on the liquid line (on these units with a sight glass just clear it, when, indoor room is at approximate set point of the thermostat). Optimum sub cooling is 12° to 15° at the outdoor unit.
Hook up your gages and put a thermometer on liquid line (small line), start the AC. Measure the temperature of the liquid line and read the pressure on your gages. Theres a temperature scale on your gages for R-22 or R-410A the needle will show you the pressure on the outer scale and if you follow it down to the R-22 or R-410a inner scale that is the saturation temperature for that refrigerant,(you can also use a temperature pressure chart), now read the thermometer, let’s say the liquid temperature( the thermometer) is 100° and the saturation temperature (the gages or temp. press. Chart), is 114°, subtract the liquid temperature from the saturation temperature, 114°- 100° = 14° subcool.

try cleaning a-coil

Hi, could be compressor loosing efficiency, i think suction pressure is to high at 85, also it could be moisture in your system, did mechanic replaces filter drier on high side of system , when he replaces evap. install filter drier on liquid line, if there isn't one, also check compressor valve, you can do that by cutting or desoldering the high side from compressor, connect charging port to compressor, conect your gauge charging port, start compressor, pump up to between 150- 200 psi shut off gauge, and leave for about 1 hr. then check pressure, if pressure decreases, then your compressor valve are leaking, if it maintain same pressure, then compressor valve is o/k. you can do same on suction side, this time in vacuum, if it holds vacuum pressure, then valve is o. k, RLA(LRA) lock rotor amps, is amount of amps compressor used to start, but will drop once compressor is running, 11.6 when operating is o/k, does your evap. compatible with condensing unit?, is it right size. check also that you're using right type of freon, check condensing unit & evap labels for right type of freon, make sure they can handle same type of freon. but check compressor valve carefully, i think your comperssor could be loosing it efficiency, compressor could be your problem. good luck.good luck

Sorry to sat but the tech has no idea what he is doing. The metering device is in the discharge valve, making that line a low pressure, not high. If the "suction" line is hotthen it is running in heat mode.

ok, on these units, if by high side line you mean the small tube going from outside to inside, that tube is actually on the low side, the metering device is in the outdoor unit. If you shut the unit down, let everything thaw then restart and find that small tube is freezing up right at the outdoor unit right away, my guess is its low on charge. I see that you put some in, make sure it is the right knid of refrigerant. they do not hold alot. Where is your suction pressure running. If you put 2 to 3 pounds with no change, you may have overcharged but that is telling you that there is a restriction in the line inside the outdoor unit, probably the filter if it has one, or the metering device itself. Let me know what you find.