[artbuc]

I am wondering how important it is to be spot-on the manufacturing charts. For example, under typical conditions (for me), I should have 13 degrees superheat entering the low side service valve (90 degrees outside dry bulb and 66 degrees inside wet bulb). How much can I vary from 13 degrees before I should add/remove R22? IOW, when does system efficiency drop-off become noticeable? If my charge is low so that I am running 16 degrees superheat, will I see a difference in my monthly electric bill? Thanks.

 

[heatycooly]

You have a plus or minus 5 degrees play on your charge

 

[Hubcap626]

I wouldn't really add or take out gas on superheat more on subcooling. You have some play with superheat with your exv. As long as your charge is right. Get thy close with the subcooling then fine tune your superheat if needed.

 

[heatycooly]

Do you have a fixed metering device or a txv

 

[artbuc]

Fixed.

 

[heatycooly]

Then if your figures are right then the charge seems fine to me what is your temperature drop

 

[artbuc]

Then if your figures are right then the charge seems fine to me what is your temperature drop

The numbers in my first post are from the manufacturer's charging chart. I have not taken any measurements yet - need to wait for warmer weather. Last year I was getting about 18 degrees drop across the evap coil.