OT: Air conditioner hissing

That reminds me... how is the fan start-up capacitor doing?

3 years ago or so, our condenser fan stopped spinning. I thought it odd that the house temperature increased one degree after I turned the A/C on. Went outside: compressor was working, but the fan was not spinning. I called my dad; he said to check the capacitor. Sure enough that was the culprit. (And, whew, what a relief; a new motor would have been about $200.) Got a new one at the appliance store on Sunrise and Coloma; good as new. I think they're only good for 5 years or so...

Now check that compressor freon level already. ;-)

Michael

On Jul 9, 9:44 am, Joerg wrote: ....

Ah. You're in the medical field. The FDA doesn't care about air conditioning. AC units are "lowest-bidder-wins" items.

Read this for grins. "How Contractors Really Size Air Conditioning Systems"

Michael

snip

if the compressor stops the expansionvalve should _close_

-Lasse

The DemoncRATs do not do blood lettings, they attach leeches to suck out the vile profit-seeking humors. Just the same we do not need any more laissez faire induced Love Canal's or Bhopal's.

Question: Is it plain A/C or a heat pump? Makes huge differences in varieties of potential problems, troubleshooting methods, repair / prophylactic methods, and replacement costs.

It's a Lennox combo propane heater and air conditioner with everything in the (huge) outside box. The A/C part is all on one side of the box and heat/air only share the (inaccessible) inside heat/cooling exchanger and circulation fan.

What I really don't get, in fact never understood since coming to the US, is the fact that the typical A/C unit does not have misters in front of the outside coil. It would be so much more efficient.

--
Regards, Joerg

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[snip]

Until the heat exchanger coil clogs up with scale. Rheem made/maybe-still-makes a water-cooled condenser.

In a humid climate the "efficiency" improvement is nil.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
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That's what active coal filters are for. Ours cost $20 at Sears. $6/cartridge, lasts thousands of gallons. Plus since it's outside those fins are rather easy to keep clean.

In CA, NV, UT, AZ, NM and so on the climate isn't humid at all. They could easily sell it as an energy-saver accessory in those markets and make some extra bucks. But I guess that's already asking too much :-(

--
Regards, Joerg

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Just checked the service manual which I found on the web a while ago (blew me away that they allowed them to be posted). It does have a TXV which pleasantly surprised me. Looked around, no signs of leakage anywhere. There would be oily residue but nada, all spiffy clean.

Seem like it's just overheating. Which, of course, it shouldn't so i'll have it checked out when the fires subside. Right now nobody in their right mind would want to work where the A/C unit is. After 1/2hr you'd work up a hacking cough.

--
Regards, Joerg

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I doubt that you would find "oily" residue. IIRC there's means to keep the compressor oil out of the expansion valve.

My system apparently lost 3# of Freon 22 over a period of more than 5 years. The serviceman said it has to get well below 1# in the system before it will ice, noting, "There's no such thing as a perfect compression joint".

...Jim Thompson

--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
     It\'s what you learn, after you know it all, that counts.

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Hi Jeorge, Simple, mineral build up! Most water supplies in the US have at least SOME dissolved mineral in it, and if you spray that on the coils, it builds up and inhibits heat transfer.

I have seen some specially designed units that do have misters installed, esp. for use in the desert areas that I live in, and then involve special mechanisms to deal with the build up and remove it, usually via a type of flexing/vibration.

-- Charlie Edmondson Edmondson Engineering Inc

AFAIK there is oil mixed in with the Freon, maybe to keep the piston lubed. At least that's what the HVAC service sites mention. They recommend to look for oily residue around joints and on the bottom of the unit's compartments.

That's a major leak. Our unit supposedly hasn't lost any in 15 years. Every time the tech was out for the six-month check-up I asked him about the freon level and he said it was just the same as last year. The temp and pressure differentials noted on the record sheets they left track as well.

And yeah, compression joints are IMHO a rather sick concept. You have to torque the heck out of them to make them tight.

At least it seems that the compressor shuts down when it's unhappy. Then comes back when happiness returns. Overall I am just not too impressed with the way such units are designed. Efficiency doesn't seem to be a high priority. I mean, icing up means cold, right? And cold needs to be transported into the house, not sit somewhere and make a glacier. It couldn't have hurt to pipe some airflow around that area.

--
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I am sure there will be more cleaning effort needed with a spray system. But that's a small price to pay for the electricity savings. Another option might be a gauze like you see on swamp cooler tracks. Then the fins would not see a direct spritz anymore.

--
Regards, Joerg

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You could use the condensed water instead of just letting it drip off the AC box? I know there's probably not enough of it, though, but it should be mineral free and it might kick efficiency a bit higher. I was thinking about collecting it to water the pot flowers (they don't like tap water).

Another probably crazy idea regarding thermal pump; you could place the radiator tubes inside septic tank and save on tubing compared to covering large area of (sometimes dry) earth? If contents were "liquefied" enough I guess the heat transfer would be quite efficient. Could a large enough septic tank be useful for that? Imagine all that crap out there just waiting to be harnessed for the good of the mankind.:)

M

They probably don't like the chlorine in there. It's round 2ppm out here. So we filter it all.

Ewww, yech. Just imagine when that stuff begins to boil after a lengthy A/C run. Greenish gases wallop out the top, then uncle Leroy lights his stogie ... OTOH:

--
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run. Greenish gases wallop out the top, then uncle

The feces would probably dry-up around tubes and ruin the heat transfer, you'd have to get in there to scrap it off the tubes after running A/C too long ;)

M

Actually, back a couple of years ago when I was trying to build out in Borrego, I looked into a geo-assisted heat pump. Was told the problem was the soil was too dry, so it didn't conduct the heat very well. I suggested putting the buried coils out under the septic field to keep them 'wet!'

-- Charlie Edmondson Edmondson Engineering Inc

But then you'd have to drink lots of beer so the leach field in kept wet. Or have a Rottweiler like ours who drinks 1-2 gallons a day and it all comes out again :-)

--
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On Thu, 10 Jul 2008 13:39:33 -0700, Joerg wrote: [snip]

My house in Phoenix had a dual system, evap (swap) cooler and regular AC. From April until late June or early July when the monsoon kicked in, the evap unit worked great, would freeze your butt off at night. Really helped with the electric bill.

--
Joe Chisolm
Marble Falls, TX