Sunday, September 04, 2011


Wotta day -- about noon-thirty, the A-coil for Roseholme Cottage's air conditioning froze up (or, more like, finished freezing up), so I got to peel the tape off and learn the guys who installed it were, shall we say, not neat freaks, nor were they much for sheet-metal screws.

I'm tellin' ya, I am giving serious thought to making up an angle-iron frame with every side a removable sheet of galvanized metal, sticking it between the furnace and the box where all ducts depart, and havin' the cooling coils installed in it. It's who-ever-bothers difficult to clean them otherwise and as for defrosting, it was Not Fun.

...About then, work called, to tell me someone was breaking into the North Campus! Oh, no, hold was my boss, tripped up by the alarm. So I had to call up there, just to make sure nothing else had gone wrong. The alarm system doesn't leave a whole lot of leeway; if you can't touch-type the keypad, you have maybe 1.5 tries. (I have the centipede's problem: I can work it fine unless I stop to think about it.)

But Tam and I got defrosting done and I hope the coil hasn't iced up again. Ran it for a couple of hours after with just the fan, to dry 'em off. We started up the AC about four hours ago and we still seem to have cool air moving. Picked up fasteners and some foil tape at Giant Home Improvement; the tape has yet to be applied, 'til I am sure I won't have to open it up again. (You do not use "duct tape" for this. It's not really for ducts. Go figure).

Update, 0000 hours: Iced up again. Dammit. I'd like to suppose we were low on coolant but it's more likely the coils are all clogged up. With, say, a paste of fine cat-hair and condensation. I'm betting that new coils may be on the horizon. Tomorrow's predicted high, 70 degrees coolly Fahrenheit, for a mercy.

I also did the first-effort stenciling of the street number. The sun set on me (it's a slow process) but I pressed on. I'm not unhappy with it by flashlight; we shall see what sunrise reveals.

The end of that effort was interwoven with starting up the grill for a couple of nice ribeyes; I also nuked a pair of white potatoes, then buttered, salted, peppered and foiled them and added them to the grill, hoping a little hardwood smoke would trickle in.

Did it work? --Put it this way: Tam finished her potato in lipsmacking delight and spent another 20 minutes on the steak, finally putting a little aside for later. The steaks were darned good, too; I was wondering how much of My Secret Recipe was in simply buying Filet Mignon and the answer is -- about 25%.

And, meanwhile, the Joys of Laundry. Which is where I'm headed next, to load the dryer for another volley.

PS: It's giant green katydid season! Photo may follow.


KurtP said...

If your coil's freezing up, an A/C guy can recharge your system for not a whole lot of money, and it'll probably cool better too.

But you probably know that already...

Keads said...

Glad you have salvaged a Labor Day weekend!

Jeffro said...

Sounds like your freon is contaminated with some water. A new receiver/dryer, expansion valve and a flush followed by vacuuming the system down before adding the recycled freon back should take care of the problem.

Hat Trick said...

Clean the A coil. Use a purpose made coil cleaning solution and rinse thoroughly. If it's still icing up you're probably a tad low on refrigerant. What 'R' number does your system use?

Skip said...

Thats why we don't live back there.
Big bugs and snow.

Roberta X said...

What's not to like about big bugs?

...All: I can't get at the A-coil well enough to clean it. I may not even be able to vacuum it. The access opening is tiny -- smaller than the smallest face of the coil. Looks like they set it on top of the furnace and set the ductwork over it, leaving just enough room to connect to it.

og said...

The cat hair is a good guess.

The mechanism of this trouble is that the coils are supposed to get cool but not cold. Water condenses on them and runs out.

If the water can be convinced to stay in place, such as with a "Wick" of cat (or dog, or human) hair, the coils will freeze it.

Having fought this battle a time or nine, I can tell you that until you get the "Wick" out of the coil, this situation will continue.

A combination of vacuuming from the inside (may be impossible) and blowing from the outside is usually the most effective. In some furnaces the offending stuff can be blown down through the heat exchanger into the fan compartment. Most fan blowers can be easily removed for service, so you could run your vacuum up through the heat exchanger.

Tom said...

Dumb question, but did you check your air filters?

Fuzzy Curmudgeon said...

Yeah, either air flow is restricted (dirty filter or dirty coil) or refrigerant is low.

greg said...

As cool as Tam makes Broad Ripple sound, I'm not sure I could live somewhere where you can tell the seasons by which bugs are running around. Ick.

Crucis said...

Our A/C only ices up when we don't replace the furnace filter on time ~90 days or so.

Old Grouch said...

I'd suspect a low charge problem... you need your pressures checked. Aa properly set-up air conditioner doesn't run it's a-coil below 32degF, specifically to prevent the problem Og and Crucis are talking about. (If it doesn't get below freezing, it can't freeze up... duh.)

Having said that, I've run into more than one residential unit that was intentionally "undercharged" in an effort to squeeze a bit more cooling out of the system. Running the coil below freezing works fine until the airflow gets reduced or the interior humidity goes sky high (like when you restart a system after returning from summer vacation, or if you suffer from kids who leave the doors open).

If yours is a premium unit, it might have a stuck expansion valve (advantage: much more efficient operation, disadvantage: more parts). A gauge test will tell the tale.

Old Grouch said...

PS- I'd suggest blowing the coil out with compressed air, or, if it's really gummed and you can handle the mess, a pressure washer. In my experience you can't get enough suction with a vacuum cleaner, even if with the pipe right on top of the vanes.

Back in the bad old days we'd sometimes clean theater ACs (gummed up with a mix of dust and popcorn oil... nasty!) with Freon direct from the tank. Lots of pressure, scrubbing action from the evaporating liquid, plus the solvent nature of the Freon itself. (Remember those electronic bench cans of TF?)

Ozone layer? What "ozone layer"?

Roberta X said...

I checked (and changed) the filter first. It was pretty fuzzy.

Getting to the "input" side of the A-coil is...not impossible; any good HVAC tech with an afternoon to kill could do it, after pumping down the system. But I'm not one, and lack the hardware and hands-on time. So it's probably going to be a Butler M-K job.

So far, the weather is cool. Payday is Friday. Any questions? ;)