Mini split -- temperature splits?

[ps2cho]

Just finished installing a 9k Pioneer mini split. Spent tens of hours on research. Electrician came today to get the wiring done and I wrapped it up.

Nitrogen pressure test for leaks, then evac and more nitrogen purges, final evac down to 120 microns on the gauge. Probably went well over the top for a brand new system, but I'd prefer too much than skip a step. Final evac stayed firm at 130 microns, felt great on it, so let the refrigerant loose. Success!

Its 103F ambient today outside and my mini split is reading 42F coming out of it. (FYI I only cut off maybe 3/4ft from the lineset, nothing that warranted trying to remove half an oz of refrigerant)

Does this sound right that outside is 103F ambient and I am pushing 42F at the inside unit? Seems TOO good!!!

 

[American Locomotive]

Outdoor ambient is completely irrelevant (for the most part, unless it is like 140°F). Temperature split is the difference between incoming and outgoing air on a specific coil. 42°F sounds about right, maybe a tad cold (depending on indoor air temp).

 

[ps2cho]

Room temperature was 73F per the unit, so a 30 degree split. I thought I read 20F splits were what to aim for? Just want to be sure it’s not an issue?

 

[PoorUB]

Sounds like it is working fine. Don't try to over analyze it. The electronics in the unit are smarter than you! If it is running, and cooling you can't do much better unless you know how to test for subcooling and what the SC for your unit is supposed to be. As for refrigerant charge, a mini-split is very forgiving. I doubt yours is over charged.

I installed sold and installed them for over 20 years and I can't tell you what the discharge air temp should be.
It also depends on humidity inside. More humidity will raise the discharge air temp so if you just started it it will be higher than after it had run for some time.

Just ignore it and if it cools the space, be happy!

 

[pcmeiners]

" I read 20F splits were what to aim for? Just want to be sure it’s not an issue?"

Just imagine the block of frozen moisture you would have on very humid days if 20 degrees was the target temperature of the air leaving the inside unit .
The low temperature you are referring too is the refrigerant temperature.

 

[ps2cho]

" I read 20F splits were what to aim for? Just want to be sure it’s not an issue?"

Just imagine the block of frozen moisture you would have on very humid days if 20 degrees was the target temperature of the air leaving the inside unit .
The low temperature you are referring too is the refrigerant temperature.

I meant 20F splits between incoming and outgoing air, not the vent temps - 20F exit temps are impossible. Ie if my room is 75F I thought I read 55F was the goal and if it’s exceeding that it’s an issue.

Sounds like on mini splits my 30F delta is OK!

 

[pcmeiners]

Got it..... enjoy your system, Nice going

"Final evac stayed firm at 130 microns,"

You can guarantee there is NO moisture or leaks in your system, if you called in an outside guy you could never be sure, that is the good part of DIY.

 

[justinjoyal]

42f is on the low side but not abnormal. Enjoy !

 

[fitter30]

Since blower, condenser fan and compressor are all variable speed/ refrigerant flow temperature drops will vary. That 18° to 24° temp drop is for conventional equipment.