Air Condition Unit
15K rooftop Unit. Went on a overnight concert trip this weekend and camped in a grass parking lot. It was exceptionally hot/humid for this time of year and we were running both A/C units as hard as ...
Forum Discussion
vjstangelo wrote:
Sorry, I should clarify my comment. My current RV is a Winnie, the prior was a TT with a Coleman Mach 13.5 AC with controls on the unit. For that unit, the temp controller was a dial on the AC which sets the point at which the compressor will cycle off. This type of unit uses a probe (or thermocouple) that senses the evaporator coil dry bulb temperature. If the dial is set too low, the evaporator coil will get to a temperature below 32F hence the coil will build up ice. If that happens, the airflow will diminish as ice builds up on the evaporator coil fins.
I am in agreement with Effy in that a 13.5 BTUH unit will theoretically generate 13.5 BTU of cooling when the compressor is activated. The wall thermostat, or cooling temperature dial on panel mounted unit only turns the compressor on and off.
The danger of running the unit (compressor energized) with an iced over evaporator coil is that this could allow liquid refrigerant to pass from the evaporator to the compressor through the suction side hose/pipe and destroy the compressor (which is only designed to compress gas, not liquid which is incompressible).
To the OP, if the unit is no longer cooling the compressor could be toast due to liquid getting into the suction line when the coil was frozen and the compressor running.
Lets clarify with correct statements
1. The roof mounted controls, the Temp sensor does NOT sense the Evap temp. That Thermocoupler sensor senses ONLY the return air thru the Air filter. These type units can and do freeze up if on LO Cool and the Tstat is set to max cool. Rarely will they freeze if set to max cool and run on HI cool.
2. WALL tstat units have 2 sensors, NOT just the wall tstat. The wall tstat tells the AC what temp it wants. The 2nd Sensor is the FREEZE sensor installed in the evap fins. This freeze sensor will NOT allow the evap to freeze, PERIOD. IF you have this type system and the unit does freeze, FIX the sensor problem, but don't state that it is normal, because it is NOT. Both the wall Tstat AND the Freeze sensor will turn the compressor OFF. Doug
