Replyusing both a sman 3 and testo 550 i get the same thing. equalizer is mounted on top of suction. i dont understand what you mean by trapped.Originally Posted by gravity
Professional Member*
Hopefully links are allowed. this shows the procedures for charging SC, look at the chart for your indoor and outdoor Bulb temps and your outdoor ambients and you will see that your 23* F SH is totally in the ranges. with outdoor ambient of 80* and indoor of 72* you can easily have a SH of 23*F.
if you use your psychrometer you should be able to get a very close reading to what you have.
http://www.hvacsalesandsupply.com/Li...20Charging.pdf
Travel and work,
Professional Member
using both a sman 3 and testo 550 i get the same thing. equalizer is mounted on top of suction. i dont understand what you mean by trapped.
Professional Member*
Hvacbry. Read that chart again. It is a chart for non Txv systems.
Professional Member*
Good chart though. Thanks.
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Trapped meaning like a condensate trap.
Professional Member
62 idwb. 83 oat. by that chart it says my sh should be 10-11 degree range. my suction line temp leaving the evap was 5 degrees cooler then at the condenser. so that puts me closer to 18 degrees sh. still have based off the chart and what my target sh was today. maybe i plugged the equalizer tube. i do remember not being able to get the tube in the hole very much. i know just the tip needs to be in.
Professional Member*
yeah the bottom of that chart is talking about non txv. the upper talks about Sub cool txv
let me ad this as it talks about TXV SC with the superheat as well.
Hopefully its formatting will stay correct. but based on this and a few other things I think he is pretty close .
Sub-cooling for A/C with TXV R-22 (Table 3)
Evaporator Inlet Air Temperature Fahrenheit Wet Bulb
57 59 61 63 65 67 69 71 73
Outside Air
Temperature DB
75 31 30 29 27 25 23 21 19 17
80 30 29 26 24 23 21 19 17 15
85 28 27 24 22 21 19 18 16 14
90 27 25 22 20 19 17 16 14 12
95 25 23 20 19 17 15 13 11 9
100 23 20 18 16 14 12 10 8 6
105 20 18 16 14 12 10 8 6 4
110 18 15 13 11 9 7 5 3 1
115 15 13 11 9 7 5 3 1 0
here's a link to a pretty good write up that can shed some light towards what he has going including the chart I posted above.
http://refrigtech.com/Knowledge_Cent...ac_system.html
Travel and work,
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What?gravity....if gauges/temps are known to be good and equalizer isn't trapped or installed on the bottom of suction i would suspect bad txv.
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Professional Member
so you think its running like it should be?i wish i could walk away from it but i have a feeling its not exactly running right
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I feel like your running just fine. only you know if its cooling well in the conditioned space.
read them links and see where you stand. after that if you feel good about it, then good deal.
you are the tech on the system, so you own it, when all is said and done.
but based on your numbers, I personally feel its very close to spec. all I know is after a week of working on it I would be burned out.
Travel and work,
Professional Member
I Think its fine, nothing runs "exactly right".
Professional Member*
I would check my TD, and if it's ok I would not be concerned about the high SH, if the TD is bad and the SH is high, you got a valve problem.
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Professional Member
I think I read the whole thread, and hope I didn't miss anything, If you change the condensing unit and kept the original evaporator with the appropriate TX valve , All things being equal it is the low head pressure I believe you said around 177 that alarms me .capacity is based upon pressure drop across the txv
by lowering what would normally be 225 to 177 You in a sense turned your 2 ton into a ton and a half, And a very efficient one at that. This happens a lot when people put 13 seer condensing units on 10 Seer air handlers, Again it was a long thread and I apologize if I missed something
I know the guy who know's the "Chiller Whisperer"
Professional Member*
If you decide to check the equalizer. Pump unit down as much as you can recover the rest. Fill her to 50psi or so nitrogen.
Score and snap with enough to braze with a small piece of copper like a coupling. It would be easy to tell if its plugged or not IMO.
Professional Member
Thats definately something i never thought about, makes sense though. I have a 3 1/2 ton unit beside this one i converted it to 410a about a month ago, used old ahu just swapped out the txv, has the same line set run, the sh is right on the money with that one. Hangs right around 12*.well i guess onto the next one. The lady that runs the Inn is prolly wondering what the heck my problem is back and forth from attic to condenser for a few days haha. I truly appreciate eveyones help with this thread, its good to know your not alone out there sometimes. Your guys advice and knowledge is invaluable. Thanks!
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3-26 degrees of superheat is fine with TEV. Aka TXV
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