DIY Mini Split Installation

[Guest boyd crowder]

Ive been using a 1 hose PortoAC in my grow closet and IM ready to upgrade and retire this incrdibly inefficient machine.

She still works ok, but  I need to upgrade my room and increase my efficiency/lower my op expenses

I believe I can install the thing , run the power and all that jazz, but my big concern is

How do I pressure test/purge/vac the system when im not an ac tech?

im not interested in buying all that kit and wanted to ask you guys who you called or how you handled the situation?

Im not in a legal state btw, so just calling hvac guy is out of the question.

I do realize that the vac pump could be used for concentrates , but man , i just dont wanna do that sort of thing yet, if i dont have to.

@dansbuds @Smokin Joe @Coastal @Nub , any ideas?

BTW, 30 years ago, i worked in aprtment maintenance so i have experience dicking around with the tree gauges and general ac stuff - just - you know - 30 years ago

[Smokin Joe]

You will need the pump, a good flairing tool, a set of gauges with a adapter for the mini and nitrogen for leak testing. I would also replace the flair nuts. I have had lots of problems with those. You can skip the nitrogen if you make sure you he connectors are good and tight. But the rest is a must. 

[Transcendence66]

The flares can be a problem. A little leak lock around the top of  brass and threads, line them up & snug them down tight. Then a 1/4 turn more and you should be fine. I'm an HVAC guy so I usually cut them out and braze the lines. You won't need a vac pump if you take your time and fit the lines up good. Then when you open the valves on the condenser, high side first the purge out the low side Schrader port a bit you should be good. I'd be glad to help. You can pm or call me. 

[Guest boyd crowder]

37 minutes ago, Transcendence66 said:

The flares can be a problem. A little leak lock around the top of  brass and threads, line them up & snug them down tight. Then a 1/4 turn more and you should be fine. I'm an HVAC guy so I usually cut them out and braze the lines. You won't need a vac pump if you take your time and fit the lines up good. Then when you open the valves on the condenser, high side first the purge out the low side Schrader port a bit you should be good. I'd be glad to help. You can pm or call me. 

thats dope , i will pm you once i get the pieces in my hands

[Smokin Joe]

8 hours ago, Transcendence66 said:

The flares can be a problem. A little leak lock around the top of  brass and threads, line them up & snug them down tight. Then a 1/4 turn more and you should be fine. I'm an HVAC guy so I usually cut them out and braze the lines. You won't need a vac pump if you take your time and fit the lines up good. Then when you open the valves on the condenser, high side first the purge out the low side Schrader port a bit you should be good. I'd be glad to help. You can pm or call me. 

Hmmm I'm an hvac guy also and would not open the valves on a system with out a vacuum much less a mini. Ever hear of non condensing gases? 

[Guest boyd crowder]

Just now, Smokin Joe said:

Hmmm I'm an hvac guy also and would open the valves on a system with out a vacuum. Ever hear of non condensing gases? 

would?

[Smokin Joe]

lol would not! 

[Transcendence66]

8 minutes ago, Smokin Joe said:

Hmmm I'm an hvac guy also and would open the valves on a system with out a vacuum much less a mini. Ever hear of non cnsing gases? 

If you don't have access to a vac pump and the lineset supplied is capped off " new" and you purge the nitro that is in there by cracking a valve the system would be fine. 

 

[Guest boyd crowder]

ok so ive thought seriously about just using external air to try and cool the room, but cutting holes in my hardwood floors or in high trafic conspicuos areas externally seems to be a 4-5 month opton per year

i need to just get right and seal the environments thus mini splits

i can pm you joe for advice as well?

[Smokin Joe]

Yes you can. You have another option also. They make a mini split that has precharged line sets. No pressure check or vacuums required. Just do like transcends said with the thread tape and leak check with soap bubbles. Not sure the brand but I have hunk it fredrich or something like that. 

[Transcendence66]

In other words cracking the high side valve and allowing the gas the purge through the evap and out the suction valve for about a 30 seconds on a small mini split especially with new clean copper would work just fine. I agree with Smokin Joe

>It would be optimal to have a bottle of nitro with regulator, vacuum pump and vac to 500 microns

Then again if the line set is not pre charged and is capped off, usually with a small static charge of nitrogen. You could do the above and purge and be ok. If you can source a vacuum pump to borrow you will be 100%

[Smokin Joe]

30 seconds of purging a system that holds maybe 2lbs of refrigerant and that charge is critical down to a few ounces? Really?

[unregistered190]

Mini-splits only are used for cooling? Correct? Or can they also function as a heater?

[Guest boyd crowder]

so i could in theory have a chance in no gear if i get new in box= NIB and recut flares and use some soap water and just follow yalls directions 

so im hearing this:

NIB systems

the exterior units are charged and ready ,

the interior is the open system , thge part that needa to be vacd, pressure tested before opening the valves 

as are the fittings can and often are poor or just beat up from the trnsit from origin

theres enough headroom for a pro to slap it together and it will work fine but an amateur could get it done if he has some pros giving him the bidness

 

 

 

[Smokin Joe]

Both. They make straight ac and heat pumps

[Guest boyd crowder]

am i missing something

i thought that atmosphere in the head unit  would be enough to water down the whole rig

[Smokin Joe]

In time it could. 

Yes the lines and indoor unit is what you evacuate. Ho long of a line set would it take? 

[Smokin Joe]

What happens when moisture gets in the system is that it mixes with the oil and crates an acid that will corrode internal parts and deteriorate the windings in the compressor causing premature failure.   

[Smokin Joe]

Here is 1 unit I found but there are others 

https://www.totalhomesupply.com/diy-mini-splits/c/329

[Smokin Joe]

And another 

https://climateright.com/mini-split-4000-12000btu-diy-quick-connect-air-conditioner-heater.html

[Coastal]

I've done a few of those, and only had issue once when a small plastic piece was leaking in the inside unit... the line sets are like putting together an air compressor fitting.you pull back the knurled bit and then it grabs the flange, then tighten on. Easy peasy but if there is a leak you need to know a guy.. and if you kink the lines you gotta know a guy. And even when your putting that big fitting on, make sure the lines are going to make for an easy connection because if you loose any charge the ac will run like shit and freeze up.., possibly killing your shit... get a high temp shut off aswell!

[Guest 3rdCoaster]

I have set a couple minisplits up...I am not an hvac tech.    

Never used the precharged line sets or the quick connect style fittings.  Leaks are not an option with this unless you can call a tech to service it or you gotta a very good friend thats knows whats up.

If you buy a standard unit, not quick connect, cut the factory flares off the line set and make your own . Throw away the flare nuts that came with the lineset and use the ones that are on the unit. Get piece of scrap and practice until you can make nice smooth flares.  A dab of NYLOG on the dye is good as a lubricant. Lots of flare tools to choose buy a good easy to use one...they are specific to r410a.  I have had good luck with the Yellow Jacket Deluxe 45 Flaring tool #60278.  

And because nobody is perfect and its better to be lucky than good  NYLOG.  Its thread sealer and assembly lube for hvac, non reactive to 410a.

 

Digital pressure gauge...al ittle overkill, but leak detection  is key.  Pull a deep vac on the lineset and let any moisture boil off.  Moisture will contaminate the refrigerant and cause it to go acidic. Then pull it back down and leave it...if your losing vac over hours you will also be losing refrigerant over time......take the time...pull a deep vac and be sure.  Time spent now will save $ and pulling your hair out later.

Use a decent 2 stage pump, with fresh oil ....it will vac down faster.    If you have a leak fix it now and retest.  

 

I dont do these everyday so I dont trust my touch to set the flares like i would the lug nuts on a tire..  Sprung for the torque wrench/flare nut set.  The units dont leak, so money well spent.

Just my 2 cents as a novice.  

 

[Guest boyd crowder]

so according to this sticky from the rag

id need 13000btu to cool my veg+flower rooms 

OK guys so this come's up as or in a thread just about every other day.... 
with this formula a room would be able to get in the 70-72 deg range even when it's 100+ but yet still maintain humidity at night time with proper air movement 

Calculating Heat Load
Heat is measured in either BTU or Kilowatts. 1KW is equivalent to 3500BTUs. 
The heat load depends on a number of factor's

1.The floor area of the room
2.The heat generated by equipment
3 the heat from lighting
4.The number of room occupants
5.The ambient temp ( your room's starting temp ) this will be added asap im still playing with the #'s

1.Floor Area of Room

Room Area BTU = L x W x 40 ( H = 8foot + 5btu per foot after that)

If you have a wall that is facing the sun add in for the extra heat

Sun facing wall BTU = L x H x 40 

2.Equipment
This is trickier to calculate than you might think. The wattage on equipment is the maximum power consumption rating, the actual power consumed may be less. However it is safer to overestimate the wattage than underestimate it.

Equipment BTU = Total wattage for equipment x 3.5

Ballast in room BTU = ballast wattage/2 x 3.5 

3.Lighting 

Lighting BTU = Total wattage for all lighting x 4

Air cooled hood BTU = wattage x 4 / 2 
@
400= 200-250 cfm
600= 250-300 cfm
1k = 300-350 cfm 
^ is just a guide cfm per hood will be on your ducting/SP....

4.Occupants
even being that im only there for 2 or so of the 12 hrs i like it to be able to handle the extra sweat when i smoke one.

Total Occupant BTU = Number of occupants x 400

Total Cooling Required

Add all the BTUs together.

Total Heat Load = Room Area BTU + Total Occupant BTU + Equipment BTU + Lighting BTU

If your using a portable a/c 

Total Heat Load BTU x 2

^this has been from threads on this site i dont have any real experince with portable a/c's other then one and it was not in a growroom but if you plan on getting one id think about one thats bigger then you thought about 


sample

so if we have a 3 x 3 room with 1k and 200 watt's in fan's/pump's 

for room we need 360 btu
for fan we need 700 btu
1k = 4000btu 
ballast in the room = 1500 btu

we would need a/c that is 6560 btu i would round up to the next size 7kbtu


air exchange 
aka intake/exhaust 
complete air exchange every 4-5 minutes is average for a grow room/greenhouse (co2 control).... 
for heat control (no a/c) i like to use 2.5 minutes {1M is best imo} 
m=air exchange in min's

l x w x h = cf / m = cfm

lets use are room from above as a sample 
3 x 3 x 8 = 72 /2.5 = 28.8 (30)
highend turn over = 72cfm
lowend turn over = 30cfm
now for the light 1k = 300-350cfm

exhaust system and air-cooled hood should be separated but most ppl cant/dont ( it's spendy) so add them together if your using 1 fan for both

the fan size we need is 330-422 remember you have duct loss (SP) in the sample room i would use a 440 cfm fan

SEER & EER ratings NO they are not the same.....

EER, or the Energy Efficient Ratio, is a measure of how efficiently a cooling system will operate when the outdoor temperature is at a specific level - usually 95°F. EER is calculated as a simple ratio of BTU's to the amount of power a unit consumes in watts. Here is an example using an air conditioner with 12,000 BTU's and consuming 1500 watts of power:

EER = BTU's / Watts

12,000 / 1500 = 8

EER = 8


While it is true that the higher the EER and BTU's, the more efficient the cooling system, many make the mistake of purchasing oversized air conditioners and ignoring EER ratings. The following is an example of an air conditioner with 12,000 BTU's and 1200 watts:

12,000 / 1200 = 10

EER =10

This would mean that this second unit can produce the same amount of cooling but more energy efficiently. Therefore, to save money on your monthly electric bill, choose a cooling system by getting an appropriately sized unit with a high EER.


SEER(seasonal energy efficiency ratio) measures how efficiently a residential central cooling system (air conditioner or heat pump) will operate over an entire cooling season, as opposed to a single outdoor temperature. As with EER, a higher SEER reflects a more efficient cooling system. SEER is calculated based on the total amount of cooling (in Btu) the system will provide over the entire season divided by the total number of watt-hours it will consume:

SEER = seasonal Btu of cooling / seasonal watt-hours used
 

full disclosure:

this post id from the rag , more here https://www.icmag.com/ic/showthread.php?t=95259

[Coastal]

Because your not dealing in a lot of space or a lot of power I think it will be way easier... I think mini splits only go down to 1 or 1.5 ton and that should  easily cover ya. Even with Co2 burner and a dehum I think a 1 ton is good for 2500-3000 watts lighting..

[Smokin Joe]

Every watt of anything in the room makes 3.41 btu's of heat so at the minimum you need to mach the heat with cool  to keep the heat from building in the room