No a/c in the Bunk

I have the same problem, '08 International ProStar. Started this road trip with good air front and back,,,at some point the blower in sleeper began to work only intermittently and now not at all. The ducts under my bunk also feel hot

 

Run the Diagnostics and see what error messages it returns.

 

If you overcharge one, you'll hear the compressor bog down and the belt start smoking. The pressure switch only shuts down the compressor when there is not enough freon in the system to keep the compressor from burning up. Overcharging is operator error and no switch can fix that. Maybe a hickory switch, lol.

 

This cascadia won't engage the clutch on the compressor if the system is overcharged. Found that out the hard way when I overcharged it one day. I started relieving pressure and the clutch engaged.

 

In air conditioning temperatures and pressures of the refrigerant are relative. This is how the process works. At any given pressure a certain type of refrigerant (R-134a) will always be the same temperature. A/C and Refrigeration does not cool anything, it moves heat to another location and dispels its.

What causes the suction lines (low pressure) to freeze is a drop in temperature as they usually run around 40 degrees. The temperature will drop if the pressure drops and will increase if the pressure increases. So low charge lowers temperature and causes freezing.

Adding refrigerant increases pressure. What most people working on HVAC without training don't realize is an overcharge will make an A/C not cool as quickly as an undercharge. It raises the temperature of the evaporator (the coil inside the vehicle). Not only that but it is much harder on the compressor too.

The reason why a stopped up evaporator or filter and a bad fan motor make the suction line freeze is because the system depends on the airflow to put a heat load on the evaporator to work correctly. With out that heat load it will freeze up because it is running too cool.

 

if both lines are hot or warm in bunk and not in cab expansion valve is bad. also if the switch valve in the bunk is bad it wont turn off the water and it will heat up the cool air coming off the core. turn off the manual valves on the heater hoses coming from the motor if you have them and if this is the problem it will start blowing cool air after the heater core cools off.

 

Actually not true...you need to have something in place to shut the compressor off in order to eliminate extreme high pressures due to maybe a plugged condenser or bad fan.