Hotpoint MAC-130 air conditioner dripping water

Question

We have a near new Hotpoint MAC-130 that we bought new a couple of months ago. We just noticed that it is dripping quite a bit of water which is soaking the carpet around it.The automatic drain pipe is connected and runs outside and seems to get water running from it, but the tank is filling anyway. I have drained it outside by unplugging the rubber drain bung at the bottom. Within half an hour or so it is dripping water again and the tank has a fair amount of water in it agin. I don't beleive the water is coming out due to the rubber drain leaking or surely the tank wouldn't fill so quickly...We make sure we keep the washable filter clean.The unit seems to cool OK and as it always has done...It is of course under warranty, but I am very curious to find out if there is anything that I can do or check myself...