seem right?

[hewitt]

tempstar 10 split unit ,model#NACO36AKA1;83F OUTDOOR,78INDOOR; Checed pressures at unit .low 65psig[38f] ,high215psig[106f]. Suction line 47f,liquid line 90f and84f air going into condenser and 98f air coming out.This is piston type metering device.I have no manufacture spec to go by.SEEMS to be fine to me any suggestions.Seasonal check:gah::gah:

[skippedover]

Having no manufacturer's spex, you'll need to rely on experience. I'd start with some measure/idea of airflow. Statics? Fan curve? The SH and SC look okay, though I'd like to see a somewhat lower SC as 16°F seems a little high. 9°F SH appears okay but not having any idea about airflow tells you nothing about system capacity. The SC could be a result of someone trying to overcome low/reduced airflow by dumping in charge. If you can locate a fan curve for the air handler and have some idea if it's in the ballpark, that might help you diagnose if there's a problem. Are the peeps complaining? 78°F indoors is a little high, isn't it? That's only a 5°F drop from outdoor temp. Remember that when you charge any system, you're charging to the existing airflow. If airflow is low, you may be able to obtain a good looking charge when referencing the gauges but low airflow will result in decreased system capacity, which means less Btu's for both sensible and latent removal.

[Texas-Tech]

9° SH is a little low but shouldn't hurt anything. Maybe a dirty coil or filter? What was your delta T?

[hewitt]

78f return air and 64 supply

[rundawg]

What air handler do you have attached to this unit? I might be able to get you a blower performance chart.

Do you have the tools to check static pressure to determine airflow?

Did you get an indoor wet bulb reading?

This will help determine what your superheat should be.

[hewitt]

67 wet bulb and no about static pressure.Air handlermodel#MVR24 36

[rundawg]

67 wet bulb and no about static pressure

Assuming you have normal airflow for this unit (1200 cfm for a 3 tons), you are overcharged.

The target superheat should be closer to 19ºf.

With that said, my guess is the airflow isn't anywhere close to 1200 cfm.



Air handlermodel#MVR24 36

That is just the Aspen Coil model number.

MV - manufactured home downflow

R - design series

2 - coil rows

4 - fins per inch ( 0=10, 2=12, 4 =14 fins per inch)

36 - tonnage (36,000 btuh)

[PM Heat n Cool]

With those wet and dry return temps your delta t should be around 17

Sent from my SPH-D710 using Tapatalk 2

[hewitt]

Oh yeah 39000btu / h.could it be restrictions at piston.Going to recheck cfm

[rundawg]

Oh yeah 39000btu / h.could it be restrictions at piston.Going to recheck cfm

I would think your subcooling and superheat would be a lot higher if you had a restriction at the metering device.

Check that airflow first, and go from there.

[Willserve]

Thats basically what I came up with 67wb/odt84=18sh you have 9. Wb67/return db78=17 you have 14. Maybe over charged and fan blowing to hard? I say this because you have low supper heat which means your temp diff should be higher but it's low 14 instead of 17. If your coil was dirty the coil would be colder also. Slow down the fan your temp diff will be higher (coil colder) but you may also have even lower supper heat. How long did you let it run when you checked everything?

[hewitt]

Let run for 15min.Alredy cleaned indoor blowerand both coils.

[Willserve]

If you go by numbers your superheat is too low. Check air flow as stated earlier. Before messing with charge you need to make sure air flow is right. It's harder without checking static but there are other ways if the install manual is there use can check cfms with heaters amps and temp rise. Could try slowing down fan speed and see if your temp diff is closer to 17, then check supper heat. Is air blowing out of vents strong, noisy?

[hewitt]

Fan is on med/high .Air blowing out of vents not rally noisy ,little strong