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Old 07-18-2011, 06:59 PM   #31
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AC Stopped Cooling??!!


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especially if the old condensing unit (compressor) was a burn out and the line set was not nitrogen purged and a vacuum not pulled. when refrigerant meets electricity via a grounded out compressor or shorted windings inside of the compressor the result is acid and that acid meeting the new compressor equals shorted or grounded out windings of said new compressor.

Not sure if it matters or not, but there was/is a dryer installed inline just before the lineset goes into the house. The tech today also did an acid test and said it came back negative(?)....he said the freon didn't smell burnt and it didn't show acid, so he said the line set should be ok.

Should I question that more?
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Old 07-18-2011, 08:34 PM   #32
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AC Stopped Cooling??!!


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Not sure if it matters or not, but there was/is a dryer installed inline just before the lineset goes into the house. The tech today also did an acid test and said it came back negative(?)....he said the freon didn't smell burnt and it didn't show acid, so he said the line set should be ok.

Should I question that more?

What acid test did he perform? Woodstock?
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Old 07-18-2011, 11:24 PM   #33
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AC Stopped Cooling??!!


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What acid test did he perform? Woodstock?
Not sure what it was called, but he had a small veil and did something with it. I didn't pay real close attention, but I did see him take a small veil out of a pouch and it seemed like he did something with the freon from one of the lines.

Should I be worried about it?
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Old 07-19-2011, 06:35 AM   #34
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AC Stopped Cooling??!!


At this point I think you've found a pretty competant tech so not really seeing as how the compressor is shot and is going to be replaced. you might want to ask him if he's going to use Acid Away regardless of if this acid test showed negative (we do an ALL burn outs/shorted compressors) and ask in a round about way how nitrogen and a vacuum affect a lineset, so as to not tell him how to do his job in other words.
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Old 07-26-2011, 01:59 PM   #35
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AC Stopped Cooling??!!


Okay, well found a new tech and for just a few hundred more I had him install a complete new outdoor unit. The new unit is a Goodman with a full warranty and parts readily available if/when it ever breaks. It was actually installed last Wednesday and I actually just got a call saying my warrantied compressor is finally in. This tech said he'd pick it up and install it back in the "old" unit and either sell it for me or give it back. Can't complain there and it'll be a discussion for another thread.

What I'm curious about now is actually the furnace squirrel cage blower. The new unit has been blowing cold, but doesn't seem to drop the temp as quick as the old one used to. Not sure if it's the intense heat we've been having or if there is another issue at hand. It seems like the old unit used to be able to drop the temp fairly easily even with the 100+ days we've had the last month or so, at least up until the last week of it's life. The new unit will keep it about 77* inside, but doesn't seem to be able to drop much below that during the day. Of course everyone has been telling me the same story lately, so not sure if it's that or something else.

What concerns me is if the blower is actually doing it's job or if something else is going on. While the old unit was out of commission, I pulled the squirrel cage and blower out of the furnace and cleaned them very well as they were very dirty and it makes me wonder if maybe the motor on the blower is working ok. I cleaned the squirrel cage and housing with water and 409, with the motor out and then blew the motor off with compressed air from my compressor. It had a small vibration before, but now that is gone and it sounds great, but I'm not sure it's blowing as hard as it used to. The air feels cold for what that is worth.

Now for the fun part, I just got home from a lunch and it's 79* in my house, thermostat is set at 77* and it's 97* outside. I checked the vents and they didn't feel cold, but the outdoor unit is blowing and no lines are frozen. It sounded like the compressor kicked on as I walked out. So not sure what is going on. Of course I have a call back in to the tech, but waiting on the return call and figured I'd ask my questions here as well to see if I get any feedback.

I'll grab my furnace info and post it here in a few as well....
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Old 07-26-2011, 02:15 PM   #36
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AC Stopped Cooling??!!


You need to get the temp on the return and after the Evap coil. The difference should be 16-20F. .
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Old 07-26-2011, 02:18 PM   #37
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You need to get the temp on the return and after the Evap coil. The difference should be 16-20F. .

Will try to do that. I have the unit off for a few minutes hopeing they'll call me soon, as I don't want to fry another compressor if something is wrong.

In the meantime the model # on the furnace is GMP 100-3. Like I said it's a Goodman as well.
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Old 07-26-2011, 03:06 PM   #38
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New 13 SEER condenser on a designed for 10 SEER evap loses capacity. So its doesn't have the capacity of the old system.
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Old 07-26-2011, 03:18 PM   #39
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New 13 SEER condenser on a designed for 10 SEER evap loses capacity. So its doesn't have the capacity of the old system.
Not sure I understand the 10 SEER part, but my old unit was a 14 SEER condenser, the coil was replaced when that unit was installed and I just realized it is capable of r410a, so I guess I could have gone with a larger SEER unit, but oh well.

I also undertand the 13 SEER is a bit less efficient than the 14 SEER, but would it not cool as well, just cost more to do so? I obviously am not the expert, but I would think the ability to cool the house would come more from the 3 ton aspect of the system than the efficiency aspect!
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Old 07-26-2011, 03:29 PM   #40
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Your correct. efficiency and capacity are not related.

Good chance then, that the system is slightly under charged. Have the guy come back and recheck it.
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Old 07-26-2011, 05:39 PM   #41
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Ok, while I'm asking other questions, I went through and checked wiring on furnace to thermostat, etc. I am curious why the furnace has a 3 speed blower if only 1 speed is used for a/c and one speed used for heat. Is the fan actually blowing different speeds for Heat and for A/C? Sorry, not trying to harp on this, just trying to learn a little something so I can try to figure this out.

It's been said it's likely low on Freon, which might very well be, but it seems eerily similar to what was going on with my other unit and everyone said it was good on freon. I'm guessing that if the fan wasn't blowing a proper speed it would freeze up the compressor and show the obvious tell tale signs of that, through frost on the lines. Lines aren't even cold!! I'm not sure this compressor is kicking on, I guess it could have developed a leak, but is there anything else? Would the Expansion Valve cause these symptoms and cause possibly even lead to the failure of my other compressor? I just don't see what else there could be.... If I were to pull the bulb off my suction line would that tell me anything about the expansion valve? I seem to recall a tech doing that once on this system and my system worked again until they could get it replaced. Or does that only work if the unit is freezing over?
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Old 07-26-2011, 05:45 PM   #42
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The blower has multiple speeds because the factory doesn't know what size A/C might be used on it.

Removing the bulb won't tell you what is wrong. The system needs to be checked using super heat and sub cooling readings. Not just pressures.
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Old 07-26-2011, 05:59 PM   #43
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The blower has multiple speeds because the factory doesn't know what size A/C might be used on it.

Removing the bulb won't tell you what is wrong. The system needs to be checked using super heat and sub cooling readings. Not just pressures.

That answers the blower question.

As for the other, I guess I just have to wait until he calls me. From the sounds of it everyone is having issues lately, would be nice if this heat would go away, but no end in store for at least another week or so.....

Sorry to keep harping on this bulb thing, it's just that two years ago I had a TXV go out and like I said a tech came out, unhooked it from my suction line and let it hang outside the unit until I could get a new one installed. I thought he said that sort of by-passed the workings of the valve until it could be replaced. If it were that simple it'd be nice to try it overnight....

I've been trying to read up on subcooling and superheat a little and I see how that is useful, of course I can't do it!!
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Old 07-26-2011, 06:12 PM   #44
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If its not a TXV/bulb problem. then doing that will cause the valve to open as far as it can, and could flood liquid refrigerant back to the compressor, and damage it.
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Old 07-27-2011, 12:01 PM   #45
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Ok, well the tech finally made it out and 5min later he had it up and running again. He seemed to instantly know what the problem was, something about the Trane Expansion Valve not working correctly with this compressor, so he installed a 'jump start'(?) in the unit to allow the compressor to bypass a delay or something with Trane's expansion valve. I'm sure you guys know more what he did than me....I hope all is good!
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