Last night I heard a buzzing noise which I couldn't pin point and the brat came in to tell us that something had happened. A smallish lump of ice had fallen on her bed.

Checking this morning nothing was particularly dirty, inside or outside. The last service was more than a year ago but I can't imagine that this was the cause. I have it running again and things seem ok. Intelligent suggestions please?

Main reasons: The majority of times I've come across it was due to the filters or the fins on the inside unit were clogged up with dirt. The filters are easy to tell, the fins not as easy to check depending on the unit. The 2nd was low freon though in theory a properly sealed AC unit the pressure should never change unless there is a fitting leak from improper seal or fitting. This is from my own personal experience over many years dealing with both home and facility ac units.

• Insufficient air flow across your air conditioner’s evaporator coil can cause it to freeze up. Your air conditioner is designed to drop the temperature of your house by taking heat from it. If your air conditioner is not properly blowing your inside air over the evaporator coil, then this heat exchange cannot take place and the Freon that should be removing heat from your home is not. Over time, its temperature will continue to drop and your air conditioner can freeze up.
• If your air conditioner is low on Freon, then your air conditioner can freeze up due to lower pressure inside the system. This is because now there is less Freon in your system, but it is still being forced to expand the same amount – more expansion equals a cooler temperature. As your air conditioner’s evaporator coil drops below freezing, the moisture in your air will freeze as it comes into contact with your coil causing it to ice up.
• Air conditioners are designed to function in a very specific temperature range. If you are running your air conditioner when the outside air is below around 62 degrees, then the pressures inside of your system will drop and this can cause a freeze up of your central air conditioner.
• Mechanical failures can cause your air conditioner to freeze up. If there is a kink in your refrigerant lines, a blower fan that is not running or is dinged and out of balance, or a clogged filter dryer, then this too will change the pressures in your system and can make your central air conditioner freeze up.

http://asm-air.com/airconditioning/air-conditioner-freezing-up/

Normally ice build up would be too much or too little coolant but in this case yes last service more than a year ago could mean blocked fins so air flow not enough to keep it from freezing. Have it cleaned - will pay for itself in electric saved.

It took me a long time to work out how these things work. Ok I'll have the coolant level checked and the fins cleaned that I don't feel capable or willing to get at myself. The thermostat was set at 25°C

Thanks guys.

Next step: insulate the f***ing ceiling!

You might also like to check that there is no split or crack in the Insulation protecting the copper pipe which carries coolant between the outside compressor and the internal fan coil unit. If there is, ambient temperature air will condense and ice up around the split and eventually fall off if it gets too heavy.

Patrick

A little bit away from from your problems with the air- con ( a real first world dilemma) wondered who the brat was? In my terms of reference a brat is a pretty derogatory term - your child ? Nice

A little bit away from from your problems with the air- con ( a real first world dilemma) wondered who the brat was? In my terms of reference a brat is a pretty derogatory term - your child ? Nice

That was my first thought too and the reason wy I did not type down the solution here. My wife and I are hoping for another child, preferrably a girl, other people have one and won't appreciate the blessing...

Edited July 24, 201510 yr by MockingJay

Had the same problem,despite regular servicing, when serviced and regassed problem was solved

We try to have our two units serviced and cleaned every six months

In fact this reminds me we need to call service man, previous service man tried to charge me extortionate amount for new gas now I weigh his bottle before he gasses

I have that to yes, it happends often, its becoz the inside unit can not reach the temperature you wish. So the outside unit, with the pump dont shut down and keeps running. In the meanwhile the inside unit will freeze little by little untill airflow get blocked, its a chain reaction untill the whole thing is stuck with ice. Clean out the dust filter inside the inside unit, this is easy, and adjust the temperature 2 degrees warmer than you got on the display. Make sure you adjust the controll not on auto. But let it blow hard.

This also happends when your room is not isolated or windows dont shut off good. Or doors with big gaps under it. Make sure the room is isolated. What helps, switch on the aircon 15 minutes before bedtime on 26 / 27 degrees. So the air have time to cool down, and moist inside the air get disposed. Ater that adjust it to your wished temperature. I gues about 24/25 degrees, thats most comforteble. If you adjust it to 23/ or -10 your ice will come back or you'll freeze to death.

Good luck.

A little bit away from from your problems with the air- con ( a real first world dilemma) wondered who the brat was? In my terms of reference a brat is a pretty derogatory term - your child ? Nice

Maybe the brat is his wife?

A little bit away from from your problems with the air- con ( a real first world dilemma) wondered who the brat was? In my terms of reference a brat is a pretty derogatory term - your child ? Nice

Maybe the brat is his wife?

I love these comments about my use of the word brat, I love my granddaughter very much, which is why I reserve for myself the right to call her the brat. I might have other terms to apply to people like you two sanctimonious prats, though.

Service time, they should check the gas at the same time but in all likelihood the drum-fan fins will be clogged up with dirt, reducing airflow and allowing water to collect and freeze up. You can normally tell by holding your fingers over the outlet and feeling the draft, seems to give up at the edges. I normally have to have my bedroom unit serviced every 9 months or so. A typical indication is the sound it makes, seems to huff and puff a bit. Temporary fix to falling ice until you can get the job done may be to run at a higher fan speed....