Help me tune my DD

[stockhatch]

Well, I finally put my DD on the old prescott, and the temps aren't great. I didn't expect them to be really good, but I may be leaving some on the table due to tuning.

The setup consists of a 600 BTU Embraco, propane, and a cap in cap evap. I charged it unloaded until frost started crawling down the suction line. It is probably overcharged as some have told me. I dont have a temp probe, so I am using the notoriously inaccurate MBM to read temps. They are -8° idle and it hits around 17° while dual priming. The temps may not be reading correctly, but thats a huge delta.

Is it my compressor, or am I over/under charged? If anything I think I am way overcharged as frost tracks all the way back to the compressor(bad I know) I have time now to mess with it, so any advice is appreciated.

FWIW, it took my 3.2 Prescott to 4.5GHz :)

TIA

EDIT: 9.5 ' of .031 cap tube tuning for 200watts

[sandman]

Well, I think your cap-tube is a bit short personally, but it should work.

Your compressor is defiantly at the end of it's capability. I'd say though that you seem to be undercharged, by the big delta T. Try adding a bit more R290.

[hatemi]

If the frost is going back to compressor even under full load then it ain't undercharged. Try tweaking the charge while uder load. With propane its easy since you dont have to worry about what % of what gas gets out.

[stockhatch]

Im about to try letting some out while its running and then adding if the temps dont improve. Would the temps be high if the unit is overcharged though? Oh well, Ill just play around with it. Updates to come :)

[stockhatch]

Well, it looks like -14° is about all it can pull down to and have any capacity. It goes from -14 to about 6° or 7° when priming. I think it was overcharged as I have no frost at the compressor any more. I think I am going to call it good for now. Is it possible that my cap tube is too long reducing my capacity? Or maybe its my thick evap base. Anywho, my neighbor is giving me a fridge tomorrow, so if it has a larger compressor I may just put it in this setup and see if thats my problem. I have a feeling it is. I think this compressor is just too small for what I need.

Thanks.