Tech Tips








TECH TIP: Putting a larger displacement compressor on a vehicle rarely makes it perform better and in some cases it can actually decrease performance. Most systems are designed for specific goals. These goals are determined by a number of factors: glass area, interior space, projected heat load, engine operating RPM, just to name a few. After all these factors have been calculated, the heat exchangers are designed for a specific BTU range. The compressor is then selected for the application.



TECH TIP: The parallel flow condenser is by far the most efficient condenser to use with R134-A refrigerant. The multi-channel construction o and multiple passes the refrigerant makes through the condenser allows maximum heat transfer. The smaller tubes and wide surface area allows the most refrigerant to come in contact with air flowing through the condenser fins.

The reasons for this efficiency is also one of its major drawbacks. These small tubes that efficiently transfer heat are so small that they trap any contaminants in the system that tries to pass through them. Flushing will not remove the trash from the condenser. This trash will create a restriction in the condenser and make the high side pressures go up. This forces the compressor to work harder and possibly fail.

If there is a situation where the system needs to be flushed, we strongly recommend changing the condenser. This will cut down on comebacks and also will help extend the life of the AC system.

PTAC6292 Condenser

Receiver Driers / Accumulators

TECH TIP: AC Maintenance - Always flush the A/C system to remove any contaminates and replace any parts that cannot be flushed. Always replace the drier anytime the AC system is opened. It is also a good practice to use inline suction filters to help catch any foreign material.


Expansion Valves / Orafice Tubes

TECH TIP: The most common block failure is loss of gas charge inside the power element head. Plugged-up expansion valves cannot be flushed out and must be replaced. When replacing a capillary type expansion valve, make sure the capillary coil or bulb is property attached to the outlet side of the evaporator line and well insulated with prestite insulation tape.



TECH TIP: When contaminates build up on the evaporator fins - such as dirt, dust and other debris - its ability to absorb and remove heat from the cab can be severely reduced as well as restricting the air flow. To maintain peak performance, regularly clean the fin area with a fin comb and solvent and change the cab air filter if applicable. Take special care to not bend or damage the evaporator fins in the process.

Evaporator_27-30531 MASKED


TECH TIP: The refrigerant oil cool can often provide us with some idea of the compressor and internal system. Black Oil indicates carbonization caused by air (moisture) in the system. Brown Oil indicates copper plating caused by moisture in the system. Grey or Metallic Oil indicates bearing wear or piston scoring. Piston scoring may be attributed to high head pressure caused by system moisture.

R134A30 FREONblank