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Old 07-31-2012, 04:34 AM   #76
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Adding R-22 increases suction temperature???


Yep, still sounds like its over charged.
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Old 07-31-2012, 07:02 AM   #77
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Adding R-22 increases suction temperature???


Quote:
Originally Posted by psehorne View Post
Current split (after removing R-22) is 17F

I have checked the gauges - just a few minutes ago:
Suction Line Pressure/Temp: 65psi/40F
Suction Line Temp Measured: 45
Superheat: 5
High Side: 240 PSI
OAT: 88F
Wet-Bulb: 17C/63F
I'd have to agree with BT, overcharged. Using the formula from earlier and plugging in your newest numbers the superheat would need to be 10(.5)f. You're close, very.

63 wb x's 3 = 189
- 80 = 109
- oat 88 = 21
/ 2 = 10.5 superheat.
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Old 07-31-2012, 12:01 PM   #78
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Adding R-22 increases suction temperature???


Sorry, I forgot to answer these question earlier.

Quote:
Originally Posted by turnermech View Post
Are you taking this temp near the low side line set port (like with in a few feet)?
I am taking the suction line temp about 3 inches from where the copper tubing enters the heat pump housing... about 3 inches from where the blue hose is attached.

Quote:
Originally Posted by turnermech View Post
Test you gauges by checking the pressure in your R-22 tank and then testing the temp of the tank (once you prove your thermometer). then use P/T chart to see if you gauges are correct. test both gauges
My gauge set is brand new Yellow Jacket, just received a few days ago. Of course, that doesn't mean they couldn't be reading wrong. But I really doubt that. (As mentioned in one of my earlier posts, my ~30 year old gauge set had a problem; I decided it was time for a completely new set, particularly since a set of hoses cost almost as much as the complete set up.) I will, however, do as you suggest and report back.
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Old 07-31-2012, 12:03 PM   #79
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Adding R-22 increases suction temperature???


Quote:
Originally Posted by Doc Holliday View Post
I'd have to agree with BT, overcharged. Using the formula from earlier and plugging in your newest numbers the superheat would need to be 10(.5)f. You're close, very.

63 wb x's 3 = 189
- 80 = 109
- oat 88 = 21
/ 2 = 10.5 superheat.
Yes, as well as consulting Payne's chart, after my post reporting those numbers I remembered to compute superheat with your formula.
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Old 07-31-2012, 12:13 PM   #80
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Adding R-22 increases suction temperature???


Quote:
Originally Posted by psehorne View Post
Sling psychrometer provides the following readings:
  • Dry bulb 25C
  • Wet bulb 17C
  • wet bulb depression is 8C

The chart says this is [EDIT:50% RH should be 44%]. I find this hard to believer. Our local airport is reporting
  • Temp 31C
  • Dew Point 15C
  • Barometric Pressure 29.94
which translates to 38% RH according to http://easycalculation.com/weather/w...calculator.php and my Psychrometric Chart.

I find it hard to believe that the humidity inside my air conditioned house is higher than the outdoor humidity.
I took my sling thermometer and one of my analog dial-type hygrometers outside last evening. Indoors the analog hygrometer was showing about 35% RH; outdoors it went to 42%. Although the readings on the sling thermometer changed from 25C/17C (50% RH) to 31/22 (45% RH), the RH went down instead of up! Go figure!

So I now don't trust my thermocouple or sling thermometers. The only instrument that seems to provide accurate temperature readings is my digital infrared thermometer.
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Old 07-31-2012, 12:18 PM   #81
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Adding R-22 increases suction temperature???


Quote:
Originally Posted by psehorne View Post
I took my sling thermometer and one of my analog dial-type hygrometers outside last evening. Indoors the analog hygrometer was showing about 35% RH; outdoors it went to 42%. Although the readings on the sling thermometer changed from 25C/17C (50% RH) to 31/22 (45% RH), the RH went down instead of up! Go figure!

So I now don't trust my thermocouple or sling thermometers. The only instrument that seems to provide accurate temperature readings is my digital infrared thermometer.
Although I still don't know the accuracy of my analog hygrometers, at least the one I took outside moved in the correction direction; it showed an increase in humidity over indoor humidity. And both of them read a few % less than the RH being reported by the local airport ASOS. (Note: Airports report current temperature and dew point - requiring conversion to RH)
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Old 07-31-2012, 03:37 PM   #82
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Adding R-22 increases suction temperature???


Not uncommon for the outdoor RH to be lower then the indoor RH in the summer.
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Old 07-31-2012, 04:40 PM   #83
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Adding R-22 increases suction temperature???


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Originally Posted by beenthere View Post
Not uncommon for the outdoor RH to be lower then the indoor RH in the summer.
Hmnnn.... didn't know that. I do believe that there is little to be wrong that would cause an actual wet-bulb thermometer to read incorrectly. So things are starting to fall into place.
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Old 07-31-2012, 04:47 PM   #84
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Adding R-22 increases suction temperature???


At 70F and 50%RH, the air contains 85.2378 grains of moisture per pound. Heat that air up to 90F with the same 85.2378 grains per pound, and the RH is now only 40.2%
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Old 07-31-2012, 05:50 PM   #85
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Adding R-22 increases suction temperature???


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At 70F and 50%RH, the air contains 85.2378 grains of moisture per pound. Heat that air up to 90F with the same 85.2378 grains per pound, and the RH is now only 40.2%
That may be... under controlled circumstances.... but...
My a/c is removing moisture from the air via the evaporate; so I suspect that my indoor humidity is lower than outdoors. In addition when taken outside my analog hygrometer showed an increase in humidity... as expected.

You and the other member of the forum have been very helpful in educating me. I don't want this to turn into a debate of scientific facts; so please don't take offense to my disagreeing with you on this topic. Your HVAC knowledge and experience are very important to me and much appreciated.

I disagreed with turnermech on the temperature of ice.
Quote:
Originally Posted by turnermech View Post
any mixture of water and ice will be 32 every drop of water and every inch of ice. this will stay constant until all ice is melted or all water is frozen.
Quote:
Originally Posted by psehorne View Post
I would think that if the temperature in my freezer is -10F, that would be the temperature of the ice until it is warmed up by the tap water I put in the container along with it.
I hope he didn't take offense either; again, his input has been very useful, right on target, and much appreciated.
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Old 07-31-2012, 06:33 PM   #86
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Adding R-22 increases suction temperature???


no offence to disagree of water ice but your not think correctly. the water can not be lower than 32 or it will be ice. the ice can not be warmer than 32 or it will be water. the two together have to be 32 untill all ice is melted or all water is frozen. That is undisputable fact. No matter what temp the ice is when enters the water. for the ice to cool the water to even 31.99 all water would have to change state to a soild (ice in this case). for the water to increase in temp the ice would need to change state from solid to liq. The two when mixed will need very short amount of time to adjust to each other but no way around them being 32.

another problem is 65 = 37 or so degrees in the R-22 Pressure temp relationship not the 40 degrees that I think you posted. 40 = right aroulnd 68 psi. Not that big of a deal but your super heat is lower than you posted.
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Old 07-31-2012, 07:33 PM   #87
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Adding R-22 increases suction temperature???


Quote:
Originally Posted by psehorne View Post
That may be... under controlled circumstances.... but...
My a/c is removing moisture from the air via the evaporate; so I suspect that my indoor humidity is lower than outdoors. In addition when taken outside my analog hygrometer showed an increase in humidity... as expected.


Actually, thats the way it works in the real world also.

If you take 20f air with a RH of 70%, and heat it to 70F, its RH will only be 9.7%.

The warmer air is, the more moisture it can hold.

You should calibrate all of your hygrometers.
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Old 07-31-2012, 10:07 PM   #88
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Adding R-22 increases suction temperature???


Quote:
Originally Posted by turnermech View Post
no offence to disagree of water ice but your not think correctly. the water can not be lower than 32 or it will be ice. the ice can not be warmer than 32 or it will be water.
This topic started because I stated that when I held the infrared thermometer very close to the surface of the ice water mix it read lower than 32 - actually 30 degrees at times and 31 at other times depending on exactly where it was pointed. What I was stating is that the infrared thermometer's pattern was tight enough when held close I could not keep from pointing at an ice cube (and thus reading the temperature of the ice cube which I still believe can be less than 32 degrees, much less) and when held further away the pattern spread out enough to read the 'average' temperature of the area that pattern was spread over (and thus was 32 degrees).
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Old 07-31-2012, 10:12 PM   #89
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Adding R-22 increases suction temperature???


Infrared thermometers, commonly known as lasers, refract light. They need to be within a range of something like 6 to 8 feet from the object to properly take it's temperature. If an object is dirty than that refracted temperature of the dirt is what is being tested. They can only test surface.

I never use 'em once I found that out.
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Last edited by Doc Holliday; 07-31-2012 at 10:17 PM.
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Old 07-31-2012, 10:44 PM   #90
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Adding R-22 increases suction temperature???


Quote:
Originally Posted by turnermech View Post
...another problem is 65 = 37 or so degrees in the R-22 Pressure temp relationship not the 40 degrees that I think you posted.
Ah! You are correct. I made a mistake.... imagine that, and I had such a perfect record.... Thanks for pointing that out to me.

I am finding these new gauges harder to read than my old ones, because the low pressure gauge goes all the way up to 500 PSI (to protect the gauge from damage by high pressure) while my old ones only went to 150 PSI, so the resolution is not as good with the new gauges.

Quote:
Originally Posted by turnermech View Post
Not that big of a deal but your super heat is lower than you posted.
Actually the superheat is higher than I posted.
Quote:
Originally Posted by psehorne View Post
  • Suction Line psi/temp: 65/40
  • Suction Line temp: 45
  • Superheat: 5
Should have posted
  • Suction Line psi/temp: 65/37
  • Suction Line temp: 45
  • Superheat: 8

I just checked. Current readings are:
  • Suction Line psi/temp: 70/42
  • Suction Line temp: 50 (still using infrared thermometer)
  • Superheat: 8
  • Wet-Bulb: 65
  • Required Superheat: 8 per Payne chart, 10 per the formula
  • OAT: 95
So things look pretty good. However, I will do as you suggested and remove refrigerant until system is obviously undercharged and then add it back until proper superheat is obtained.
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