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Discussion Starter · #1 ·
It was 100 degrees today in Delaware. My upstairs HP unit isn't keeping up but it is putting out some cool air and is running continuously. It is now 10PM- 88 degrees outside and the temp inside is down to 78. I have about 60FT of line length and 17FT of lift. The unit is a Trane XB-13 2 ton model. ANY ADVICE APPRECIATED- thanks.:)
 

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has it been properly maintained? freon level checked, indoor and outdoor coils cleaned etc.
 

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Discussion Starter · #3 ·
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Thanks for reading Yuri! The unit and house is only 4 years old. The indoor unit and ductwork are in the attic. I have good soffit and ridge vents but no power exhaust vent. Last night the outside temp dipped to 85 and the unit was able to finally shut off at 72 degrees. It's now 90 degrees in late morning and the unit is running continuously but so far keeping up. We'll see this afternoon- it's supposed to get to 100 again.
 

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Since it is in the attic, is the duct sealed to keep from pulling in hot attic air. What is the temp in the attic space during the day.
 

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Discussion Starter · #5 ·
update

Thanks gregzoll! I'm not sure if my ducts are sealed well or not. I was getting 65 to 69 F out of the registers. The outside temps started off at 85 and went to 102. The unit ran continuously and the space temp rose to 78 before it dropped again overnight. My attic space temp was 115 to 120! I have soffit vents and ridge vents. Do you think I need a powered exhaust vent?
 

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I would say no to the power venting in the attic.I would repeat what yuri said in that the coils should be clean.If you are religious about changing the filter your indoor coil should be ok.
The ducts in the attic should be sealed (with mastic) at all joints and insulated.
If you have flex duct runs they should be as short as possible. as stright as possible with metal elbows at bends.They should be hung according to manufacturer specs and they should be sized according to flex duct sizing indicates for proper air flow.
In a good number of cases like yours there is a shortage of return air back to the blower so that shiould be checked out by an experienced duct man.One or two extra returns might be the ticket to your comfort.
 

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Hey there, REP. The same REP from over there, right? It's me, the infamous Roadhouse. Glad you could join, your expertise is greatly appreciated. Beenthere is here as well.
 

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Discussion Starter · #8 ·
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Thanks REP! I am very religious about changing the filter at least twice a year. The unit is only 4 years old. I'm certain the coil is clean. Should I check the output temp at the unit? Since the ductwork's in the attic, the supplies and the returns are both in the ceiling. There are 2 baths with 16 IN vents and no returns, and 3 bedrooms. 2 of the bedrooms have two 16 inch supplies with a 32 IN return and one has a 16 IN supply and 16 IN return. What is the best way to check for leaks? I'm not certain the charge is right because of the length and lift (see above). Any suggestions on how to get a technician to resolve the issue properly?
 

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Taking tempatures can tell you a lot.
One reading would go like this;taking a temp jyust before blower and just after the inside coil.This would tell you how much heat is being taken out of the house air.This temp ius dependant on size of couil,the CFM,and the temp of coil.
Now go back to the house and get temp of the air at the return air grille.It should be close to the temp just before the blower.If there is a bigger differance it means that the ductwork is picking up additional heat on its way to the blower.The other temp to consider is the temp at the supplyn registers.It should be close to the temp just after the inside coil.If it is not,if it is not as cold then the ductwork is giving up temp before it gets to the house.Causes for this could be restriction causing lower cfm than needed it could be the ducts arew not well insulated or loss of cfm due to faulty seal of ductwork.
The only way for you to check your ductwork would be to have something that smokes.if you go around each connection and the smoke either goes away from duct or is drawn into duct then you need to seal that connection.
If you have the above temps written down for the servive tech it will save a good bit of time.He can check the charge with super heat or subcooling to tell if you need a charge infussion.If you do then you have a refrigeration leak and you can't fix that .The tech has to find the leak and repair it.This is not a simple solder job.
 
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