This is a Mitsubishi mini-split heat pump. Today it was 62dgrees inside this room, 65 degrees outside. When in cooling set at 59 degrees the heatpump would operate for about 30 seconds and shut down. When in heat it would operate normally without shuting off. In cooling the suction pressure was about 50psi. The smaller line is also not insulated . The suction line is coming back cold. Is ther a problem or is the cooler temps causing this by a sensor or something. I saw no low or high pressure switches. Thanks Bill Pugh
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Have you cleaned the air return filters ? Wash them, don't vacuum or brush them. It damages the filter screen. Sometimes a thermostat will be out by a few degrees. If the filters are clean, try turning the temp down a bit to 65 degrees and see if the air con shuts down. ( If your room temp is showing 70, it should switch off the machine) If it doesn't turn off, keep reducing the temp by 5 degrees at a time and wait a few minutes each movement to see if and when it shuts down. If the machine keeps running, I would suggest your thermostat is shot and you will need a new one.
Make sure the indoor filters are clean. The outside unit will continue to run until the indoor reaches the temperature you have selected. Dirty filters can throw the temperature out. Its common for outdoor units to freeze up when on heating mode if the ambient air temperature is below 5 degrees Celcius.. The machine should however, defrost itself. There could be a problem with one of the pipe or air sensors on the outdoor unit.
Check the defrost board in the outdoor unit... it should have a wire coming off pins that are stamped 30, 60, or 90. If the wire is on 90, then try setting it to 60 or 30. This just enables the defrost board to check the freezestat in minutes...the shorter amount of time, the less likely the unit will freeze up.
Hello.I think they are on to something with shortcycling on temp sensor.I think it should be sampling the return air instead of (inside coils ?).A 2*f dead band use to be built in (factory installed) to thermostats to prevent on/off, but not sure in this case.Try a new sensor location(return air) and see if anything changes.
I brows the web to see the specs of your unit.In that case the unit cannot cool down the room temperature, you must consider the following:The volune of the room, it might be exceeded the specified capacity, the thermal isolation of the room, must be shield from leaks,and the materials used,the absorption of the matterial at first operation, the materials around the area will absorb coolness prior to room air, and the ambient temperature outside may affect the performance of the system,If too hot outside put a better thermal isolation inside.that helps? need thumbs up... sams_Ew0rks**
Fujitsu, Mitsubishi, Sanyo mini-split indoor fan motors operate continuoulsy. The room-temperature sensor is inside the unit, so the fan motor needs to circulate air continuouly to sense room-air temperature. This is normal operation.