Dehumidifier Frost?

I have had a dehumidifier in my basement for years. Lately, it has been frosting up on me. I haven't had a chance to tear it down yet, but should I just expect to find dirty coils or is there something else that I need to check for?

I would bet it's dirty coils. I would try to blow it out with compressed air and see if that helps.

I took it apart and cleaned everything. After running it for about ten minutes with the cover off, it started to freeze up again.

My guess is refrigerant leak / it's junk?

What is the air temp in the basement? Does the frost completely cover the coils or just part? Some units incorporate a filter, does it have a filter that might be clogged up?

Do you have a fan that you can aim at it? Air movement can help keep icing from happening in some cases, also raising it up off the floor where the air is warmer may help.

Frosting up is due to low refrigerant. Somewhere, there is a leak. Since these are generally sealed units, there isn't a provision for filling them. If you still have your receipt and info, the fine print states they are warranted for 2-5 years. If you can silver solder you could fix it, but this is one of those things that it's just more expedient to get a new one. I just had one replaced under that warranty. It was only 19 months old. They don't make them like they used to.

Frosting can also be due to limited air movement and placement in an area cooler than about 70 degrees. Certainly low freon can contribute to that also, but it's not a given.

He states it's been fine for years...thus it's not an airflow or temperature problem. That leaves low/leaking refrigerant.

Update: It is E36 M3.

The sides of the frame are getting pretty rusty. I suspect that it may have chafed through the copper and leaked down.

I can't really complain. I found the receipt and I bought it twelve years ago to the day.

Next rant: Holy crap, dehumidifiers are expensive!!

Woody wrote: Next rant: Holy crap, dehumidifiers are expensive!!

Yep. We found that out last month when our 10 YO one died. Ended up paying almost double for the new one.

...and you'll be lucky if it lasts half as long!

So can someone explain if there is a refrigerant leak that it causes frosting? To me it's because of a lack of air flow.

There was certainly no lack of airflow. I cleaned everything thoroughly and then ran it without the covers and filters in the same position it has been in for 12 years. There's even a large fan running right next to it.

The covers could actually keep consistent flow over the whole face of the coil and keeping it from frosting. Like a radiator shroud helps pass air over the whole radiator. Just a thought.

If it was leaking refrigerant, there would be less and less mass changing phase and you wouldn't get more cooling (and frost) but less. Like when your car has a slow leak in the AC system. Does the coil in the dash frost up? Honest question; but I don't think so... I think it just gets a little warmer and warmer until there's no refrigerant left.

I read through this link, and it might just be that the room is too cold and too little air flow: http://www.appliance411.com/faq/dehumidifierfrosting.shtml

Now that it's nice and clean, can you move it to a warmer spot? Near the water heater/furnace or in some sun light... The article suggests elevating it to get it in a warmer stratification of air.

There have been no significant changes to the room over the past 12 years. It's always been in the same spot, mounted about a foot off the floor on a milk crate. Now it's freezing up, before and after cleaning. It's not an airflow issue. That block of wood on top is there to simulate the cover that I removed and keep air moving through the coils as it should.

I have accepted the idea that the rusty unit has failed after 12 years of faithful service.