Aircon add Humidity??

[swisscraft]

Hi,

my Aircon (Cruiseair 16k BTU) runs flawless. But lately I noticed something odd: When the compressor runs in cooling the Humidity inside the boat drops quickly to 50-60%. If the compressor turns off as it reaches the desired temperature the blower still runs and the Humidity increases shortly to over 80%. Thats 10% than I would have without any Aircon on.

Any idea about this? Thanks

[hellosailor]

swiss, I'd guess that there is moisture (condensate) pooling in the system somewhere and that when the condensor is off, that extra moisture is being picked up by the airflow and pushed out into your boat. After all, that water has to be coming from somewhere.

[sailorchic34]

Check the drain on your condensate pan (under the evaporator coil). It can clog over time. Also check that the evaporator coil is not icing up due to dirty filter or dirty fins on the coil....

[simonmd]

An aircon unit will ALWAYS dry the air and reduce humidity, hence why they always have either a drip tray or a vent hose to the exterior. However, once the compressir has done its job and cuts out leaving the unit to circulate the cooled air, the humidity in the machine can then be vented back into the space it's in.

This effect is more obvious in a car which is a smaller space, if you rech the desired temp and switch to 'econ' in the car after the aircon has been running, you'll often find the windscreen starts to mist up right away for the same reason.

So, it's not 'adding' humidity, it's just putting back what it's just taken out.