How to charge a mini split a/c

[whadeezlrg]

I'm at the point of my current build that I need to get my a/c all charged up and ready to go. my problem is, I don't know how to charge a mini split correctly! lol

a friend of mine gave me a 1 ton Ideal air unit, the outdoor unit is supposedly holding the charge(he had his a/c guy remove the charge before they split it and took it out) so I'm guessing I just need to connect the lines and put it under a vacuum for a certain amount of time and then open up the refrigerant valves more or less?

I don't know that I trust my buddy's a/c guy, although he's used him a bunch of times without any issues and my grow is smaller and considerably more secure, and he'd do it for less than I'd spend on the tools to do it myself...

could anyone with more experience with mini split systems please chime in and help point me in the right direction....I searched and came up with limited amounts of info...I've watched a couple you tube vids as well.

 

[jav2043]

if the system was charged down where the gas is trapped back into outdoor unit then you should be just fine installing and releasing the gas to charge system after vacuum of course. good luck

 

[snake11]

Make sure everything is connected correctly. Leak check with nitrogen. Vacuum down to 500 micron, shut off vac and valve off, and release the charge. That's the short version anyways. Truly you would want to do a triple evac to 500 but no one in the HVAC industry does this. Too time consuming.

 

[Asslover]

What your friend did is called "pumping down". Without getting technical, all the freon is "locked" in the outdoor unit. What you have to do is connect the lineset, vacuum the lineset and check for leaks, then open both service valves. They're located on the outdoor unit right where the lineset is connected.
So yeah, the way you described is the way to do it.

 

[snake11]

What your friend did is called "pumping down". Without getting technical, all the freon is "locked" in the outdoor unit. What you have to do is connect the lineset, vacuum the lineset and check for leaks, then open both service valves. They're located on the outdoor unit right where the lineset is connected.
So yeah, the way you described is the way to do it.

You should check for leaks with positive pressure(nitrogen). A hard vac can actually seal leaks but when you release the charge the leaks will appear.

 

[Asslover]

"Without getting technical"...

 

[sureshot66]

is it an ideal with the braided flexible lineset? if so those seal and dont need to be vacumed down, if not, you need to use a vacume pump...you "should" still have enough freon in the system,though ive moved mini splits and had to just top them off, you need gauges and freon for that, just hit me up if u have questions, im no ac pro ive just done it alot

 

[snake11]

is it an ideal with the braided flexible lineset? if so those seal and dont need to be vacumed down, if not, you need to use a vacume pump...you "should" still have enough freon in the system,though ive moved mini splits and had to just top them off, you need gauges and freon for that, just hit me up if u have questions, im no ac pro ive just done it alot

They all need to be evacuated with a vacuum pump. How else do you get rid of the air in your lines. Moisture in your lines(even the small amount in air) will cause the compressor to burn out prematurely.

 

[jav2043]

Not all need to be vacuumed. I know Ideal and Friedrich Breeze make plug and play models that come pre vacuumed lines which are sealed and won't let in air or moisture when disconnected. Pump it down, disconnect and once installed in new location release the gas and good as new.

 

[snake11]

Not all need to be vacuumed. I know Ideal and Friedrich Breeze make plug and play models that come pre vacuumed lines which are sealed and won't let in air or moisture when disconnected. Pump it down, disconnect and once installed in new location release the gas and good as new.

They may make this claim but I would be amazed if their cheap products were able to disconnect without letting any air in. If this was the case why would you even have to pump it down? Wouldn't their airtight/vacuum tight seal keep all the refrigerant in? Avoid ideals anyways as they are pieces of shit. Stick to Fujitsu and Mitsubishi. These are good reliable brands. You get what you pay for.

 

[Asslover]

They may make this claim but I would be amazed if their cheap products were able to disconnect without letting any air in. If this was the case why would you even have to pump it down? Wouldn't their airtight/vacuum tight seal keep all the refrigerant in? Avoid ideals anyways as they are pieces of shit. Stick to Fujitsu and Mitsubishi. These are good reliable brands. You get what you pay for.

With the plug/play units, they don't get pumped down when one needs to move it. Because the line set is pressurized no air will get sucked in when the line set is disconnected. (after the service valves are closed all the way, of course). Because a small amount of r410 escapes when the line set is disconnected, they recommend you check the charge after disconnecting/reconnecting 5 times.
The only plug/play unit I'd ever use is Friedrich.

 

[sureshot66]

Avoid ideals anyways as they are pieces of shit. .

if you read the post, he was given an Ideal 1 ton, so avoiding it seems unlikely at this point

 

[snake11]

if you read the post, he was given an Ideal 1 ton, so avoiding it seems unlikely at this point

Many others have not made purchases yet so advising them what equipment is no good might help. I am just relating my hvac experience trying to save folks time and money. Fujitsu, Mitsubishi, and daikin are the only ones I would use.

 

[snake11]

With the plug/play units, they don't get pumped down when one needs to move it. Because the line set is pressurized no air will get sucked in when the line set is disconnected. (after the service valves are closed all the way, of course). Because a small amount of r410 escapes when the line set is disconnected, they recommend you check the charge after disconnecting/reconnecting 5 times.
The only plug/play unit I'd ever use is Friedrich.

Thanks for clarifying. The other posted stated pump down before moving which would pretty much guarantee air in the lines. Friedrich is also considered a cheap mini split. The brands I stated have far fewer problems.

 

[snake11]

I'd vacuum it down anyway just because I refuse to run a dangerously poisonous (when exposed to heat) HFC/CFC refrigerant...and as others have mentioned, because you cannot guarantee there isn't some air in the system already. It's not like they pull a vacuum on those units for 48 hours at the factory or anything. In an assembly line they pull 30-120 seconds of vacuum and that's all. I'd personally prefer a deeper vacuum on my refrigeration systems, in addition to switching refrigerants.

If you want maximum cooling, with minimum power draw, and maximum safety in the event of a discharge, use a mixture of R290/R600a refrigerant. Better known as propane and isobutane, in a 60/40% to 80/20% ratio. (60/40 is direct replacement for R-12, in terms of operating pressures. More propane = better cooling, but higher pressures, and may not be plug and play in some systems.)

Outdoor sporting goods stores have little cans (1/2 lb) of 70/30 (or better) isobutane fuel mixture, for those little "Jetboil" camping stoves, which can be adapted to your charging hose with about $20 worth of brass fittings. The can valve with threaded top is known as "Lindal B-88", FYI, but the fitting you're looking for is called "Jetboil to disposable propane tank" adapter. Pick up a bottle of standard Coleman propane camp fuel to complete the charge; less than $10 total refrigerant cost. Use a standard disposable propane bottle extension hose with proper fitting added (hose barb with clamp, brass valve, etc) to connect it to your charging hose.

Pull a deep vacuum on the system, using a high quality vacuum pump (JB Eliminator is always a good choice; old school quality, made in the USA) and hold it for a long time....however long you can, to ensure there is no leaks, and more importantly, to boil off the water.

There should be plenty of oil already in the system, so just connected your isobutane can to the low pressure port and start charging, while the system is turned on to max A/C. (Be sure to bleed all the air from your charging line first!) Use a postal scale to weigh out the full amount of isobutane. The typical total charge needed for this mixture is going to be 1/3 to 1/2 of the factory (R12/R134a) charge amount, so take this into account. At this point the compressor should start short cycling (cycling on/off rapidly) indicating a low charge. Now connect your propane tank and slowly start adding it to the system, bringing the charge up to normal, using the low side pressure (30-35-ish psi is your target) cycling frequency (not too often) and evaporator exit temperature (not too much frost forming on the line) as your guides.

Last step: enjoy ICE COLD A/C for your ladies even on the hottest days, with less power consumption than previously. You'll also find that the A/C system's life is extended, from the lower operating pressures, especially if it was an R-134a system.

Putting flammable explosive gas in a system not designed for it is a quick way to make it in the Darwin awards.

 

[bobblehead]

Grow rooms catch fire sometimes. Using propane in the lines is a bad idea. Ever have 20lbs of propane unloaded in a grow room fire? I have. Refrigerant isn't that expensive.

Ideal-air line sets are nice. 100% plug and play. Unfortunately the air-handler burned up...


HFC-R134A - IS NOT labeled FLAMMABLE, but NOTE: it has a rated Ignition
Temperature (F>) of 1390°F to 1436°F subject to different MSDS sheets from
manufactures. Why isn't IT labeled FLAMMABLE?

R134A FACT Sheet



Propane Chemical formula C3-H8
(3 parts carbon - 8 parts hydrogen)

Octane number 125
Motor Fuel R/M 104
Cu. Ft. Air Required to Burn 1 Cu. Ft. Gas 23.5
Ignition Temperature 920 degrees to 1020 degrees Fahrenheit
Maximum Flame Temperature 3600 degrees Fahrenheit
Flashpoint L.E.L. (Lower Explosive Limit) 2.4%
Flammability U.E.L.(Upper Explosive Limit) 9.5%

PROPANE GAS PROPERTIES - Allgas, Inc.

 

[bobblehead]

R134a flammability test - 970° Celsius

 

[bobblehead]

It's easier to treat exposure to refrigerant than burns from fire. Hot smoke is enough to cause epiglottitis and kill you if you aren't immediately intubated or trached. A fire in progress is exactly what burned up my air-handler. I minimize fuel for fires when designing my grows nowadays.

 

[sureshot66]

Holy hijack, wills that is all just terrible advice who wants to go thru all that to charge a mini split? I get it's a little colder than really cold

 

[queequeg152]

who the hell told you r600 or r290 was intrinsically more efficient? it is not.

systems have to be designed, more or less, around a particular refrigerant.

pumping r600 or a blend into a r410 minisplit will offer terrible results.

there are however... hydrocarbon blends that can successfully replace r22 refrigerant in existing systems... with just a few minor swaps. price r22 and you will see why.