HVAC splits?

I would like to get a HVAC double split system and have already figured almost everything out about my install but these two things.
1. I can do all the work except refrigerant lines. I can't have a HVAC guy come into my rooms. He/she will need to do the evacuation and fill of refrigerant at the condenser outside. You supposedly have to have a cert to buy the refrigerant or I could do it all.
I want a condenser with two evaporators/controllers, for two rooms.

2. I already have a 220v wall socket on a 40amp breaker that's not being used in the space so I don't need to direct wire into the breaker box. Do the typical split condensers have a simple connection that can be wired into with a fat 220 elec. cable with the right 220v plug?

1.the refrigerent gas come with the AC. its already inside the condenser

you just need to verify the refrigerent connections with high pressure nitrogen (mini 20bar). if it pass the leak test then use a vaccum pump to purge the circuit from air. disconnect the pump without letting any air in. then use an Allen key to free the gas inside the outdoor unit.
plus it will look strange if you dont want to let them in

2.yes you have 1 power supply cord for each AC

kingromano said:

1.the refrigerent gas come with the AC. its already inside the condenser

you just need to verify the refrigerent connections with high pressure nitrogen (mini 20bar). if it pass the leak test then use a vaccum pump to purge the circuit from air. disconnect the pump without letting any air in. then use an Allen key to free the gas inside the outdoor unit.
plus it will look strange if you dont want to let them in

2.yes you have 1 power supply cord for each AC

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It was suggested to me that I buy the premade hook up package that has the refrig lines included. The shortest ones I've seen are 15ft with 25ft available too. I probably don't need 7' of refrig line to each evap/controller. Then I can cut them in half and hook up all the premade lines inside and have the open ended lines exiting the building and the tech will have to put new connectors on the lines going to the condenser and then do the evac and add if necessary. Thus keeping the tech outside the building.

these are not real AC
it's more a bag of problems than anything
not reliable

kingromano said:

these are not real AC
it's more a bag of problems than anything
not reliable

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I work in an office that uses one [mitsubichi] has been running for 10yrs.

gwhunran said:

You supposedly have to have a cert to buy the refrigerant or I could do it all.

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I found cylinders of R-410a on Amazon and bought a bunch of cylinders before they pulled them off. Sometimes you can find refrigerant on craigslist.

kingromano said:

these are not real AC
it's more a bag of problems than anything
not reliable

Click to expand...

Dude, a split AC unit is what most homes have, wtf?

The only real problem with most split AC units is they don't support low ambient temperatures. If it's gets lower than 60F outside the evaporator coil inside starts freezing into a block of ice. Sometimes you can install a freeze kit but it's not an energy efficient fix like the inverter style mini-splits have. On an inverter mini the power is converted to DC and back to AC to provide any frequency the unit wants in order to run the compressor and fans at variable speeds. When it's cold outside my mini's barely even run the compressor and the fans stop or barely turn on the outside unit.

gwhunran said:

Do the typical split condensers have a simple connection that can be wired into with a fat 220 elec. cable with the right 220v plug?

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As long as the unit doesn't require a neutral this should work fine, if it requires a neutral (some do but not many) then the receptacle would need one also. In this case the receptacle would serve as the disconnect, of course this should be located outside by the condenser for service lock out purposes.

I watched the Youtube videos on the install, bought a vac pump from harbor freight tools . They are precharged so you do not need to buy refrigerant. If it did not come with a line set you can buy make your own it is not that hard. I have now put in 3 already and love them. They are very reliable my first one I installed 6 years ago

Note: You can purchase r-410a off ebay, some sellers don't ask for a license #. May just order your refrigerant and go that route.


Something to consider, a nitrogen pressure test. Yeah a vacuum can be pulled on the line set / connections and wait to see if there is any leakage BUT the vacuum pulls loose connections together where gas under pressure pushes them apart. It is much easier to verify the system is sealed using a nitrogen pressure test. The evaporator coil is usually marked with a max PSI, don't go past that. I test my units at 400 PSI with nitrogen, release the pressure after confirming no leaks, pull a vacuum and then weigh in the charge. Doing the nitrogen pressure test step also purges out any air/moisture in the line set making the vacuum pulled even more effective.

Renfro said:

I found cylinders of R-410a on Amazon and bought a bunch of cylinders before they pulled them off. Sometimes you can find refrigerant on craigslist.

Dude, a split AC unit is what most homes have, wtf?

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wtf ?
if you read my message you will see i speak about models with premade connections
i say it again, these are not reliable, any guy working in HVAC will tell you

you want to use air conditionner ? learn the job or hire a real hvac guy to install PROPERLY your air conditionner
don't use supermarket AC with premade dudgeons connections in your grow room

kingromano said:

wtf ?
if you read my message you will see i speak about models with premade connections
i say it again, these are not reliable, any guy working in HVAC will tell you

you want to use air conditionner ? learn the job or hire a real hvac guy to install PROPERLY your air conditionner
don't use supermarket AC with premade dudgeons connections in your grow room

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I don't think the OP was referring to such a unit. I don't use any units with pre-filled line sets / quick connects. I do use mini splits. The OP is using a normal split type unit from what I gather.

gwhunran said:

I would like to get a HVAC double split system and have already figured almost everything out about my install but these two things.
1. I can do all the work except refrigerant lines. I can't have a HVAC guy come into my rooms. He/she will need to do the evacuation and fill of refrigerant at the condenser outside. You supposedly have to have a cert to buy the refrigerant or I could do it all.
I want a condenser with two evaporators/controllers, for two rooms.

2. I already have a 220v wall socket on a 40amp breaker that's not being used in the space so I don't need to direct wire into the breaker box. Do the typical split condensers have a simple connection that can be wired into with a fat 220 elec. cable with the right 220v plug?

Click to expand...

what wall is the socket on? Outdoors or indoors?
it would be rare to see an outdoor wall socket @ 220v unless in europe or something.
you are planning on running a plug all the way inside im guessing? Yeah you can do that but..
Most codes require an electrical disconnect box with a solid whip going to the condensor

Inside and less than 20' to breaker box

gwhunran said:

Inside and less than 20' to breaker box

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so you plan on running an extension cord to the outdoor condensor? Also what condensor model and type are you using?

gwhunran said:

Inside and less than 20' to breaker box

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That looks like a 20 amp 240 volt receptacle. Are you sure thats gonna be enough for the AC unit? Usually they need more like 40 - 50 amps but they vary. Chances are you will need to run a new circuit for the AC.

gwhunran said:

2. I already have a 220v wall socket on a 40amp breaker that's not being used in the space so I don't need to direct wire into the breaker box. Do the typical split condensers have a simple connection that can be wired into with a fat 220 elec. cable with the right 220v plug?

Click to expand...

The receptacle you pictured is a NEMA 6-20R that is rated for 20 amps

Renfro said:

The receptacle you pictured is a NEMA 6-20R that is rated for 20 amps

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good shit~ this is why people should always hire a licensed person to do the job right. Too much liability if you do not know what you're doing.. Do your homework. There is a reason people call it a "trade". Perhaps you may know some people and can pull some favors? @gwhunran

I've installed numerous "head pressure control" units in order to allow the use of a/c in the winter. As Renfro stated, the fan on the condenser barely moves. If you go this route, I would seriously look into a heat strap to wrap around the compressor. That being said, I've never used them on mini splits but I would assume the same principles apply.

Renfro also hit the nail on the head with pressure checking the system with nitrogen prior to vacuuming it down. 400psi is a little high for my likings but still highly recommended. We also strived to hit 500 microns during the vacuuming. Remember not to take your gauges off until you've released your refrigerant otherwise you will lose your vacuum (even if it is a split second) during the disconnection.

Systems usually come precharged for up to 25' line sets.

I would seriously just find a reliable contractor to do the complete install. I don't see any good contractor giving you any type of warranty on an install where the homeowner completed 1/2 the work. Although it seems simple enough, there's a lot of small variables to take into account, and if missed they could cost you more than just your crops.

That's a 20 amp plug and you have all 20 amp breakers I don't know where you're getting 40 amps from based on those pics. whatever AC you get you're going to need to make sure it can run on a 20 amp circuit