Trends Portable Air-Con Maintenance

air con cond conditioner conditioning aircon air-con air-conditioner air-cond
I have a Trends PC15-AM1B portable air-con, rated at 15,000 BTU/h, that was giving me a lot of trouble, spending almost as much time on repair as working. I figured out a maintenance schedule for it that seems to work, no breakdowns in a year, so I'm writing it here and hopefully it's helpful for someone.

Problems

• Firstly, it leaked, although this model is supposed to automatically evaporate the water. Sent for repair - came back, still leaked. I don't think anything was spoilt, just that it condensed water faster than it could evaporate it.
• The manual said you can connect a hose to it to drain the water away, so that's what I tried. This was worse - after a few days, the air-con became very noisy, then the compressor stopped working, only the fan was left running. The display showed the error E3, which the manual said was a gas leak but the repairman didn't think so. This happened no matter which drain I connected the hose to.
• The repairman said the inside was very dirty when I sent it for servicing.

Short Solution:
I found out that setting the fan speed to the lowest stopped the leaking by more than 95%. Looks like reducing airflow reduced condensation (expected), but it reduced condensation more than it reduced evaporation, i.e. it was now able to evaporate the water fast enough.
I also cut a plastic tray to fit under the air-con to catch any leftover leaks. Plastic because water + electricity is bad, and a conductive tray would have been worse.

Maintenance

Now this is the complicated, troublesome part that I found out, through trial-and-error. I haven't managed to open up my air-con so I don't know what the inside is like. It's like doing surgery blind.
Reducing the fan speed, as mentioned before, greatly reduced leaking, but what about the dirt accumulation? This is what I do:

• Every week, at the most every 10 days, flush the air-con with water.
• TURN THE AIR-CON OFF AND UNPLUG IT (do I need to say this?)
• To do this, move the air-con so that the lower water pipe (on the side with the air intakes) is near a drain. Remove the plug and let the dirty water drain out. Observe that there are clumps of dirt in the water.
• You need to prepare a funnel and hose that fits over the air-con's water pipes. Put your plastic tray below the other water pipe to catch water that's going to leak out. Have a mop ready.
• Remove the plug from the other side (this is located at about the middle of the air-con's height, near the stickers). A bit of water will flow out. Quickly put the hose over the pipe. Slowly (over about 1 minute) pour 1 litre of water into this pipe. Water will flow out the other, low pipe. See more dirt being flushed out. At this point, some water may leak from the bottom. This is what your tray and mop are for. Sometimes it leaks, sometimes it doesn't. I haven't figured out the pattern yet.
• When the water from the low pipe slows to a drip, replace that stopper.
• Pour 500-1000 ml more water into the middle pipe, filling the air-con. I've found it's able to hold this much water without overflowing. The thing is, even though it's not very good at evaporating water, it really doesn't like running without water. To the point of spoiling.
• Remove the hose and stopper the middle pipe. Done!

It seems that running the air-con dry (by draining the water from either pipe) is very bad for it and will eventually kill the water pump. So counter-intuitively, adding some water to it helps. If you notice it becoming much louder than usual, sounding a bit like sucking from an almost-empty cup, turning it off and adding some water seems to help.

Every 2-4 weeks, wash the filter.

All these problems stem from the water pump, so I'm wondering if I should I have gotten a model that DOESN'T evaporate the water instead, which has no water pump to spoil.

• No water pump to spoil
• Empty water as often as you like - no leaks
• Emptying water removes the dirt as well and keeps the air-con clean

It's very odd, it seems that the lower-end model is more reliable.

Disclaimer: do this at your own risk, this is only general advice, etc.