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Discussion Starter #1
I have Goodman 3 ton I just installed about a month ago. Have been running for a couple of days now the outside temp on the big line is 45 F out side and 47 F air coming out of the vent is this a good temp ?????????? :eek:
 

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Discussion Starter #4 (Edited)
Condenser fan or furnace blower

Condenser fan or furnace blower, I found that my furnace blower is running on high for ac. That is a I know about the blower's and the outside one is also working correctly. What I have is this
Danfoss Orifice #73
new (model # CAPF3636B6) Goodman Evaporator Coil 3 ton 13 SEER does both R-22 or R-410-A. My compressor is a Goodman CKL36-1D it's a 3 ton 10 SEER R-22 unit used . Bryant 394D-0036100 :thumbup:
 

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I'm Your Huckleberry
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The only way to properly charge a system is to verify proper air flow. This can be done with a manometer. Please tell me you have one.

If not then you can make sure that your evaporator is clean and that you have no air restrictions in the return and hope that all ductwork was designed properly as with "proper" air flow through the coil and return we can assume for you to have proper cfm.

Then you check superheat for a fixed orifice. You will need your gauges to determine suction temp at the evaporator and then a thermomoter to check temperature of the low side suction line at the condenser.

You subtract the temperature of the vapor leaving the evaporator (that temp read from your gauges hooked to the low side) from the temperature of the low side line at the condenser to get your superheat. Add refrigerant to lower superheat, remove (recover) refrigerant to get it higher.

Of course you would need to know your target sh as well to determine if you need to add or remove refrigerant.
 

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Discussion Starter #7
dont know

I don't know about the charge , my friend use to do HVAC for a living he did the charge and the wiring, solder he had gauges and some kind of temp thing that hooked to the big line and a ambient temp sensor. I installed the brand new evap coil on top of the furnace and the plenum everything is sealed. I used some 100% silicone on the stuff that wouldn't seal correctly . I got the condinser unit from friend that could afford to get a hole new system. I bought a new evaporator coil in box and a orifice and dryer filter, I had talked to Alpineair about what I was installing they sold me a the matching parts. :thumbsup: Oh and I remember he pumped it down for about 45 min - something
 

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if your indoor temp out of a register is 47 then the temp going back to the furnace should be around 70 to 75. measureing the out door line temp doesnt help if you dont know the pressure of the line
 

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Discussion Starter #9
Thanks

I am trying to find out if the temp's sound correct, But I guess it all depends on the equipment that I have. He is an older guy he hasn't done ac in a while, just checking his work with the PROS here. Tonight I will check the cold air return temp :yes:
 

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Do you have a thermometer that you can stick into the supply grills and the return grill? This would give us the temperature difference of the air which is a caveman way to determine what is going on but I wouldn't recommend just doing that and saying you are good.

With a fixed orifice, any fixed orifice and not a thermostatic expansion valve metering device, you are playing with fire when it comes to the charge. If you have a low superheat than the chances of liquid refrigerant making it back to the compressor greatly increases and liquid going back to the compressor will kill the compressor.

You can remove that fixed orifice and install a txv which maintains a constant superheat. Of course you'd need your friend's help with that as you'd have to pump down the system (hold all the refrigerant in the compressor and close the compressor off to the line set), unscrew and remove the piston and screw in the txv, cut open the low side line just before the evaporator and install a metering mount (shreader fitting) which requires a brazing rig to close the lines back, mount the metering bulb and then open the lines back up.

These days txv's are what is used for the most part. Then you can charge by subcooling which is the opposite of superheat, how much heat is removed from the hot liquid refrigerant coming from the condenser.

Can you spend a little more for peace of mind and buy a txv?
 

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if your indoor temp out of a register is 47 then the temp going back to the furnace should be around 70 to 75. measureing the out door line temp doesnt help if you dont know the pressure of the line

at 46 degrees f, r-22 pressure would be 77.6 psi. Of course that 46 (or 47 in this case) is the superheated line temp and not the actual refrigerant temperature coming from the evap so the temp and pressure of the refrigerant would be slightly lower which would mean you are very close as to what the return air temperature would be.
 

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Discussion Starter #12 (Edited)
Done

I just called my wife and had her check difference between the 2 , it's 20 f difference. I asked them guys at alpine air about that txv valve they said that I didn't need one that the orifice would work better , and so i believed them because that part was around 100. 00 vs the 10.00 I spent on the orifice . I even called them a second time and talked to someone else they told me the same thing, I remember him saying something about 80 psi is where it was a at and then he was done.
 

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I just called my wife and had her check difference between the 2 , it's 20 f difference. I asked them guys at alpine air about that txv valve they said that I didn't need one that the orifice would work better , and so i believed them because that part was around 100. 00 vs the 10.00 I spent on the orifice . I even called them a second time and talked to someone else they told me the same thing, I remember him saying something about 80 psi is where it was a at and then he was done.

Fixed orifice works well when it is very hot (90 f and up) but when it cools down outside the coil capacity and efficiency of your system decreases, co-inciding with a lowered superheat which fluctuates with a fixed orifice. This means that the temperature of the air coming from out of the registers could increase when the ambient temperature decreases.

That will not happen with a txv, ever, unless it goes bad. The system efficiency (coil capacity which equates to air temperature) stays the same regarldess of ambient temperatures.

Your 20 degree difference suggests you have a properly charged and well running system. As a rule of thumb and a rule of thumb only, a 20 degree difference is industry standard so it sounds like you are as close to perfect as you can be.
 

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Discussion Starter #14
Thanks

Thanks for all of your help, I live in Missouri where the summer temp's and humidity is very high. This system will get it's butt worked off this summer. :thumbup:
 

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That will not happen with a txv, ever, unless it goes bad. The system efficiency (coil capacity which equates to air temperature) stays the same regarldess of ambient temperatures.
Not really, as this would defy physics.

A TXV only maintains super heat, it doesn't maintain a constant evap temp. One day the evap may be 40 degrees with a 12° super heat, another day the evap may be 48 degrees with a 12° super heat.
 

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Coil capacity stays the same is what I meant.

You should get Modern Refrigeration and Air Conditioning. And read and study it. Then you'll see the flaw in that statement also.
 

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nope, we just went over it class for the past three months so it's studied.
The explain how the coil can be at the same capacity with an entering air temp of 70°F at 50%RH at a coil temp of 45°F, as a coil at 40°F, both with 12°F SH. They can't and aren't. Either you misunderstood, or your teacher/instructor is wrong.
 

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I'm Your Huckleberry
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The explain how the coil can be at the same capacity with an entering air temp of 70°F at 50%RH at a coil temp of 45°F, as a coil at 40°F, both with 12°F SH. They can't and aren't. Either you misunderstood, or your teacher/instructor is wrong.
The only way the temperature of the coil would defer would be by way of capacity, amount of refrigerant in the coil, so with a txv that refrigerant level would be maintained, correct?
 
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