how to check the charge of an air conditioner

[kimberlite]

how to check the charge of an air conditioner? my units have only one schrager (bicycle type) valve?
thanks
eric

[MikeMoore]

If you unit is AC you take a clamp on amp meter and measure the running current. if the voltage is correct for the system then under current indicates under charge and over current over charge. Running current should be within 3 to 5 % of design

[kimberlite]

if the unit is under current--how do i determine how much to fill the unit and how do i fill it?
fair winds,
eric

[jreddington]

Unfortunately, the only way to completely accurrately check the charge on an A/C system is to empty it and recharge. You then measure the charge by either counting the small cans you use, or by putting a big tank on a scale and filling until the tank lightens by the amount you''re trying to fill.

To "top off" you have to have a bit of a feel for the normal cycling time of the compressor and it also helps to have a glass port in the system (properly charged when you have small bubbles through the glass).

To add refrigerant using a small can, use the proper adaptor kit. ALWAYS keep the can upright so you fill with gas, not liquid. A liquid slug will ruin the compressor.

As the refrigerant expands from the can it will get cold which will slow down the filling. One way to speed it up is to have a pan of warm water and place the can in the water as you fill.

One the system seems to be working OK stop filling. Overcharges can damage the system.

If you''ve lost all or most of the charge or the system has been opened for service, you have to completely evacuate the system and hold it under a vaccuum. Air in the system will interfere with the refrigerant and any moisture in the system with cause acids destroying the system. A vaccum will pull out both the air and evaporate and pull out the water. Before doing this you should replace any dessicant (which pulls out any remaining moisture). This may be incorporated into the accumulator so you might have to completely replace this.

If you''re not completely familiar with refrigeration systems, this is work best left to a professional with the experience and specialized equipment to do this, including legally required refrigerant reclaimation. Intential release of older refrigerants is illegal.

[KenD]

The Answer you recieved from jreddington is a bit on the Backyard under the tree mechanic side. Your unit has specs which should tell you how many pounds of refrigerant are required for proper operation It''s why they make gauges!Get a pro to service the unit.