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stevanrk · May 25, 2007, 07:49 AM

Hi I have an Amana system that is maybe 15 years old. I can find out if anyone needs to know but I'm at work now so that will have to wait. Anyway, I have noticed that the cold air is not so cold anymore. The past few days that cold air problem has been compounded by the condensing unit not coming on when the a/c is trigerred. So all that happens is the furnace fan comes on, but not the condensing unit (CU) like before, when it was working. Today I watched the CU come on for two seconds and turn off again. There is a fuse like box that says it is not a fuse and I pulled that out and cleaned the terminals, but no luck. Also I noticed that the insulated tube that is supposed to be frosty cold is only mildly cooler than ambient outside air and the smaller hot line is not that much warmer than the surrounding air. Is the compressor bad, out of freon, etc?? For your amusement and potential useful information, I used the CU last year as a work horse as I was cutting through some lumber with my circular saw and I cut into the radiator tubing and all the gases escaped. My fifth bid on the CU decided not to replace the A/C unit (both the CU outside and the coils inside), but instead just solder the tubing back together and fill up the lines with freon. This held up for a year and here we are today. Sorry for he long post, but I hope I have somewhat clarified what is going on. Any help would be much appreciated. Thanks in advance.
Regards,
Steve

Stratmando · May 25, 2007, 08:55 AM

There is a good AC guy on this site, for now,
If I was to guess, filings or contaminated lines may have caused a problem.
Didn't hear lines were evacuated. Would say, can't be good.
May not be that.
Thermostat puts 24 volts out to contactor, and to compressor and motor.
Check contacts and check when compressor shuts off, Is contactor still energized(pulled
In)

stevanrk · May 25, 2007, 09:01 AM

I keep hearing about checking and sometimes replacing the contactors, but don't know where that is. Is that the thing on the wall next to the condenser outside?that has a pull out fuse disconnect? Sorry, but I have no idea.

Stratmando · May 25, 2007, 11:42 AM

Outside should be a box "Disconnect"ing power to unit, Where these wires go inside the Compressor unit, Your big wires connect to this First, Going out of contactor, goes to Fan motor and Compressor.
24 Volts from thermostat feed power to contactor control wires on side of contactor to pull
Down Line and Load Contacts

stevanrk · May 25, 2007, 12:47 PM

OK before I go testing the contactor I want to update some other findings. I opened up the coil box over the furnace and the lower coils are frosty and frozen while the upper ones are room temperature. There still is no difference in the tubing going into or out of the coil just like the outdoor tubing from the condenser. Would a faulty thermal expansion valve do this? Hope this helps you help me. THanks again.
Regards,
Steve

hvacservicetech_07 · May 25, 2007, 07:47 PM

I think you may just be low on freon, and the unit is cycling on and off for that reason, it may have a low pressure/ loss of charge switch. It may be that the service guy didn't get the leak fixed or maybe he missed one. Did you see ice build up on the indoor coil?

stevanrk · May 26, 2007, 07:26 AM

Thanks for all the replies. Yes there is icy frost buildup on the lower copper loops that enter the evaporator inside the home. No frosty lines outside. Both lines feel the same actually. So here are the findings so far.
1. Frosty ice on inside evaporator coils (inside house)
2. No temp difference between the high and low lines at the condenser outside
3. If thermostat is set to A/C cold, the condensing unit will either start and go for a while (20 minutes or so), OR it will come on for 5 seconds and stop and stay off for a while (10-30 mins).
4. When condensing unit IS on the contacter is IN. When it is off the contacter is out and I can turn it on if I hold the contacter in manually.

Those are all the findings so far. Does this still point to a low freon charge/potential leak? If yes, should I get the same guy to come out and give me a discount for not doing a thorough/complete job just a year ago? THanks again in advance.
Regards,
Steve

hvacservicetech_07 · May 26, 2007, 01:28 PM

I think you should call the company back because to me it sounds like you are low on freon, but keep in mind that your system is 15 years old and another leak could have started somewhere else. Hopefully the company you hired will be honest and tell you that they didn't get it fixed right, if the original leak is the problem.

stevanrk · May 29, 2007, 04:50 PM

OK, so I had an A/C service guy come out (same guy who fixed my leak last year) and after trying to put some freon into the system, realized that the pressure did not go up. Airflow was good in the house with no blockages. He diagnosed a bad thermal expansion valve and said he would have to replace the whole A-coil. I asked if he could just change the TXV and he said he didn't like doing that because the small tubing could melt. Is there a temporary fix that I could do so that I avoid this cost (he said 600$). I know that the TXV is for higher efficiency, so is there a way to bypass this feature? Or am I screwed? Thanks again.
Regards,
Steve