De-Humidifer Not Working Properly

I have a super little de-humidifier - Karda RAM-810 suitable for two bedroom house which this is. It's been absolutely super up til this week.

I just noticed that since I emptied the tank last week it hasn't actually sucked in any water, despite the motor going beautifully and everything outwardly appearing to be ok.

I know the temperature is warmer etc but it usually has something to show in the tank, even in the summer.

Any ideas? I had just taken out the filter and cleaned it.

I can see through to the inside & there is a bit of fluff which has made its way inside. If I were to undo the screws & pull the front off, would I be likely to run into trouble?

Thanks.

no, but would you be likely to solve anything, either?

My guess is something not savvy with the condenser.

Hi Toast,

Your dehumidifier probably has at least two motors in it.
It has a fan motor that usually runs all the time.
It also has a refrigeration compressor (just like the compressor in your fridge or freezer) that only runs some of the time.

Dehumidifiers often have a switch (or two or more) to monitor the water container to prevent the refrigeration compressor from operating when the water container is either full or not present - this is to prevent the dehumidifier from dripping water onto the floor.

It is possible that one of these switches might simply be dirty or stuck, or the water container not put back in the right way, or the door for the water container compartment not quite closed properly, etc. Depending on your dehumidifier, there may be mains power on these switches, and there is probably water about in close proximity to those switches, so it is generally a good idea to unplug the power cord before investigating.

The compressor makes the evaporator cold by sucking the refrigerant gas out of it, which lowers the boiling point of the liquid refrigerant inside it to a low temperature. The fan blows air through the evaporator (looks like a small car radiator or just a big coil of pipe) where the moisture in the air condenses to liquid or freezes to ice! The compressor forces the refrigerant gas into the condenser (another miniature car radiator) under high pressure, which raises the boiling point of the refrigerant and allows it to condense to liquid at a temperature that is higher than the evaporator. The fan also blows air through the condenser to keep it cool. The high pressure liquid refrigerant from the condenser then flows from the condenser to the evaporator through some kind of flow restricting device - often a capillary line (very small diameter copper pipe) or a mechanical throttling valve (often temperature/pressure controlled). If / when the evaporator gets clogged up with ice, the dehumidifier then has to do a defrost cycle - usually this means simply turning off the compressor so that the relatively warm air flow has a chance to melt all the ice, but there could be an electric heating element in there to speed up a defrost. You are unlikely to find on in a domestic dehumidifier, but some refrigeration systems (eg heatpumps) have a "reversing valve" that makes the condenser and evaporator switch roles - this is also known as a "hot gas defrost".

Cheers