20 deg. superheat, why?

[comfortmaster1]

Operating Condition:
AC been running for a while.
House is cool. Humidity not high.
Delta T = 17
Don't know how much CFM.


Outside: Ambient = 84
CU discharge air = 104
Liquid line temp = 101
Suction pres. = 68 psig
Suction line temp = 65


System is 2 yrs. old.
3T cu & coil.
96,000 btu furnance.

Everything is fine. But why is my superheat so high?

Only thing I could think of is the unit is undersize. Maybe in the afternoon, but not in the evenings like it is now.

[amd]

Only thing I could think of is the unit is undersize. Maybe in the afternoon, but not in the evenings like it is now.

ugh. That statement tells me that you shouldn't be putting gauges on your own system. Call a technician.

Size has absolutely nothing to do with superheat.

[amickracing]

True... but I know many pro's who don't know how to measure superheat... +1 for this guy! lol

Best advice I have for you is to learn about super heat.... look in the for your interest area of this site and do some reading. There are many things that can determine super heat... 20 deg might be fine, heck, it might even be too low in some condions!

[Mr Bill]

Originally posted by comfortmaster1
Operating Condition:
Delta T = 17

I still think Delta T is calculated by subtracting the wet bulb temperature from the dry bulb temperature, this is what I was taught back in the dinosaur age, we called the differential over the coil "return to plenum" TD but he I am so mixed up now I don't care anymore. :D

[Mr Bill]

Originally posted by comfortmaster1
Everything is fine. But why is my superheat so high?


have you tried checking it with another temp. gauge just for grins?

[psychometric]

Originally posted by comfortmaster1

House is cool. Humidity not high.


What exactly is the problem? Did I miss something?

[servicetech5]

Is that a 96,000 BTU furnace with a 5 ton blower on a 3 ton A/C

[Wild Leg]

re: 20

What would you like for it to be?

[Mr Bill]

Originally posted by psychometric

Originally posted by comfortmaster1

House is cool. Humidity not high.


What exactly is the problem? Did I miss something?

My guess would be with that high of a SH the compressor will eventually burn up, sort of like running you car with the radiator low on water.

[allstar08]

there is no way to know if you have a 5ton blower from your info. and you for sure r not measuring superheat. delta t as i know it today is the temp difference return to supply or some say temp the difference accross the indoor coil. sub cooling is a better method if it has a txv, but that is another animal. call a tech or punch in superheat on you browser and learn.

[Mr Bill]

Originally posted by emoney1971
and you for sure r not measuring superheat. delta t as i know it today is the temp difference return to supply

And I say Delta T is calculated by subtracting the wet bulb temperature from the dry bulb temperature, could someone find this out for sure and report back to headquarters,and if you prove me wrong please direct me to your findings . :D

[jrbenny]

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