A/C upgrade/install, questions, 13x6 sealed,co2

[MagniKhan]

Need a little advice ladies and gentlemen. I'm about to finally finish off a sealed room that I have been running with at about 75% done.
I'm looking for some input from any HVAC pro's that have some experience in this area.

Currently it's set up with 2x1kw and 2x600w Air cooled lights on a mover. 14,000 btu portable unit cooling a 13x6.5 room ( 10 x 6.5 production space). Other various pieces of equipment not really germain to the current subject.

I'm setting up a 2.5 ton split a/c and adding a cO2 burner. At this point I will drop the portable and the air cooling on the hoods and let the a/c cool them as well as the burner.

I currently have (from a old house project ( Oh the heady day's of 07') a new Nordyne air handler set up for r410a. At first glance I though I would use a Quick Connect Air Conditioner and Coil , but it looks like the coil won't fit into the handler without modification to the handler.
I've seen others that have had to get vacuum pumps and gauges to get their mini-system running when a flange on a line set is bad or needed to replace a line for one reason on another, it's not like I can have my A/C guy in for a repair on this unit....it's all me.

So I though wtf, i might as well get the tools (or at lest price it out and factor in the differential) and do it myself. I have varied skill set, so I think I can pull this off.

So now I'm thinking on getting this compressor unit, refrigerant, line set and a drier.
Since I'm not going to do this for a living, how important is it to get a good vac pump? What size would be best?

Cheap MAPP gas unit or a small oxy/ac unit?

Nitrogen purge, is it a must? If so, I see a tire unit from Harbor freight that looks like it would do the job with a $50 flow gauge.

Or should I just get the whole unit with quick connects?

 

[Puscifer]

2.5 tons is awfully big for only 3200watts, even if uncooled. Short cycling could be an issue.

 

[MagniKhan]

2.5 tons is awfully big for only 3200watts, even if uncooled. Short cycling could be an issue.

Don't forget the Co2 burner*, and it it get's crazy hot here in the summ.....er um...most of the year. Also, I had thought about that (while obsessively going over the pro's and con's of the current plan) and figured that I could add on a 5x5 veg closet to help balance the system in case of issues.


Also the more I've thought about it, I may just go back to the "Quick Connect" unit and modify the air handler to fit. I'm not to bad of a metal worker and I think I can just make a new back panel and front access. A little glue and fiberglass insulation and it should work as good as anything else..hmmmm still obsessively going over it and double checking,,,,,,here in the 11th hour.
One way or another, I order tomorrow.

P.S, I'll start posting some pics as this go's along if anyone is interested. I've been a little dormant since we lost Evlme,OGH and some of the other "Florida Growers Thread" regulars.
God I miss Evl. Thanks for passin' on tha' love!


* = The item shown may or may not be the exact model, unit and place the I purchase said unit from.

 

[MagniKhan]

2.5 tons is awfully big for only 3200watts, even if uncooled. Short cycling could be an issue.

Do you think, it would be better to downsize to a 2 ton? Though as I said above, it gets real hot here I did insulate the shit out of the room. It's a room built within a room from Rmax and insulated with r14, then sealed with heavy plastic. I can draw a heavy enough vacuum on the box to make the door difficult to open.

 

[Rolldaddy]

The bigger minisplit will work better for you. It's not an overkill, specially if your running bare bulb. Yes it may cycle off more but for these applications you want to be oversized. Whenever the compressor is running it is dehumidifying the room. So with ac units in grow rooms the bigger the better

A good rule of thumb to use. Each 1000k open bulb creates about 5000 btu's of heat and a vented one creates about 3000 btu's of heat.

 

[Puscifer]

The bigger minisplit will work better for you. It's not an overkill, specially if your running bare bulb. Yes it may cycle off more but for these applications you want to be oversized. Whenever the compressor is running it is dehumidifying the room. So with ac units in grow rooms the bigger the better

A good rule of thumb to use. Each 1000k open bulb creates about 5000 btu's of heat and a vented one creates about 3000 btu's of heat.

Not quite. All things being equal; the bigger the compressor the less it will run. The less it runs the less it dehumidifies. Even with a mini split, it is very important to size it correctly. Cycling on/off does not cool/dehumidify as well as an (inverter) mini split that runs at a constant low speed.
MagniKhan, a 24k btu (2 ton) mini split would be perfect for a room that size and with that wattage, especially with the good insulating. The mini split is easier to install than the unit you linked, is MUCH more efficient and won't cost you much more.
A decent 3 or 4 or 5 cfm dual stage vacuum pump and a set of r410 gauges/hoses and you're set. The mini splits come with complete install instructions and even list tools that are needed.
Here's are a few examples. Mitsu being top brand, then Lg or Friedrich, imho...
https://www.goductless.com/LG/LS240...cat6091&mainCat=cat6102&subCat=&trail=1004:LG

https://www.goductless.com/Mitsubis...mainCat=cat6102&subCat=&trail=1004:Mitsubishi

https://www.goductless.com/Friedric...&mainCat=cat6102&subCat=&trail=1004:Friedrich

Also, since your room is not that big you may want to consider co2 tanks instead of burners. Burners add heat AND humidity. Some growers don't mind or it's not what they consider a lot of heat/humidity but my mind set is to remove as many heat sources as possible from the room since i'm paying to cool it

 

[Rolldaddy]

That's exactly what I said that the bigger the compressor the less it will dehumidify. To each his own. a grow room usually has higher humidity levels then a regular room in a house.

 

[guyyug]

From my experience, if you are going to do one install, just get a cheap 2-stage 3-5cfm vacuum pump with a manifold guage, let it run a couple of hours, shut the valve connecting the pump (through manifold) into the lineset and make sure your gauge holds the vacuum for several hours. Then open the valves from your compressor. I would not worry about purging the lines unless they are used (not new) and/or they do not have a cap from the manufacturer keeping them clean.

Now, you know that getting a professional to do this with proper equipment (purging the lineset as well) is the best bet, however, for the risk involved in having someone there is NOT worth the very small added piece of mind. Installing it yourself will also void any warranty these systems have, but getting a few years out of them at least should be easy. I am basing this solely on MY needs, yours may be different.

Also, getting a compressor with inverter will make the unit more quiet and save you some money. Mini splits are pretty cool units, but they do not move near as much air as an air handler, but for the size of your room, I think it would be the best bet

 

[Puscifer]

Rolldaddy, sorry if I misunderstood you.

 

[MagniKhan]

I really appreciate the input guys, it's been a help to make up my mind, though some of it maybe to late.

On the burner verse tank, I can't really see myself moving around tank of co2 every month and I have NG so I thats why I went that route.
I've already obtained a new 2 ton compressor unit, 25lbs tank of r410a, dryer and a 35ft. line set for $1170. Remember I already had the air handler and coil and I had to make the order today.
I did step it down from the 2.5 ton and stepped away from the quick connect compressor coil combo.

In the end I'll move my veging back near this area and hook up to this A/C system, so if I need to balance the system I can seal this area and open it up to the cooling to get a longer cycle. Once the veg is moved back here I can up the two 600w lights to 1k lights ( I can drop the A/C and various other equipment that area and relocate the watts), so add that to 8x54w for the veg lights and that should do it. Yes the romms is well insulated, but hell it gets fucking hot here in tha' dirty south.
Can I use the amount of burners in my burner to manipulate the burn time to make adjustments to the cooling?

On the tools I found a Robinair 15500 VacuMaster 5 CFM Vacuum Pump for $179 and a set of gauges for $40.
Also found a nitrogen tire tank set for $179. I'll just get a $50 flow gauge and I should be set to purge the lines...right?

http://www.ebay.com/itm/Refrigerant-Manifold-Gauge-Set-R410A-R404A-R22-w-5ft-Hose-Set-/110789619346

 

[Treetroit City]

That's exactly what I said that the bigger the compressor the less it will dehumidify. To each his own. a grow room usually has higher humidity levels then a regular room in a house.

I'm confused here. So are you saying it's better to have an ac unit that doesn't dehumidify so much?

I would think you would want your ac to do much of that work.

Am I thinking wrong here?

 

[MagniKhan]

I'm confused here. So are you saying it's better to have an ac unit that doesn't dehumidify so much?

I would think you would want your ac to do much of that work.

Am I thinking wrong here?

What he was saying here is if the unit is to big it will cool the room to fast and not run long enough to lower the humidity in the room.

 

[Rolldaddy]

No prob pascifer.

What we were talking about is that if a unit is undersized the compressor will run longer cycles which will take out the humidity out of the air. If he already got a 2 ton he will be fine. For growing IMO having an oversized unit is the way to go. That way it's not a constant battle to keep RH up at good levels

 

[Puscifer]

Sry to leave ya hangin MagniKhan, my forte with grow room cooling are mini splits. I can't imagine installing a split system is much different but I've only ever installed mini's.

 

[MagniKhan]

Sry to leave ya hangin MagniKhan, my forte with grow room cooling are mini splits. I can't imagine installing a split system is much different but I've only ever installed mini's.

No problem at all, thanks for the input. And for what it's worth I did follow your advice/warning and down sized the unit from the 2.5 ton originally selected to a 2 tone unit. It should arrive early next week along with the line set, etc.

I've ordered the vacuum pump and gauges today. Once I get a few more items together I will start snapping pics.
I still have to pull the wire for the Compressor and the handler, set a disconnect for each and build a stand/intake for the handler.

 

[Bobbito Blaze]

Harbor freight has a 3 cfm vac pump works great I'm a HVAC cert. and have used this pump myself make shure you get 410 gauges. Does the system come precharged? how long is the line set gonna be? depending non the length of line set you might need more feon. You can solder the lineset lots of people do it that way I prefer a hard braze I done them with mapp before but if its cold windy forget it and you might toast your valve remember to wrap valve with wet towel before braze or solder there is a ruber seal in there that you can melt and then it will leak on you. Best bet is silver braze rod with acytaline tank. You dont need nitrogen just leave your linen under vac for a while and make shure it holds. Hell you dont even need the vac pump.n First pressure test line then Just pull the shrader valve out of the low side valve get your line wrench and crack open your high side valve and I mean a crack allow freon to flow threw to low side for few seconds and while freon still flowing carefully reinstall shradder and open valve all the way then crack open your low side valve you'll be all good. Just a cheap option

 

[MagniKhan]

Harbor freight has a 3 cfm vac pump works great I'm a HVAC cert. and have used this pump myself make shure you get 410 gauges. Does the system come precharged? how long is the line set gonna be? depending non the length of line set you might need more feon. You can solder the lineset lots of people do it that way I prefer a hard braze I done them with mapp before but if its cold windy forget it and you might toast your valve remember to wrap valve with wet towel before braze or solder there is a ruber seal in there that you can melt and then it will leak on you. Best bet is silver braze rod with acytaline tank. You dont need nitrogen just leave your linen under vac for a while and make shure it holds. Hell you dont even need the vac pump.n First pressure test line then Just pull the shrader valve out of the low side valve get your line wrench and crack open your high side valve and I mean a crack allow freon to flow threw to low side for few seconds and while freon still flowing carefully reinstall shradder and open valve all the way then crack open your low side valve you'll be all good. Just a cheap option

The 6 cfm unit to ordered was only $174 with shipping, not really to much a difference in price.
The gauges are for r410a and were only $74 shipped, all the lines are included.
As for the pre charge, yes it is. The line set will be about 30 feet, so just for shit's a giggles I ordered a 11.5lbs. tank of r410a, I figure there's enough to top this system off once and recharge the whole unit if I fuck up.
The brazing will be done with silver rod and oxy/acy, and on the nitrogen...call me crazy, but I'm far to much of a perfectionist to not.

Thanks for the options and the input!

 

[guyyug]

Sounds like you got it figured out, but you might check to see if the schrader valve on your gauge will work on that compressor, I know r410 systems use a different one than r22 usually come with, but being it is for r410, I'm sure you are good, (you know how cheap ebay stuff can sometimes screw you on stuff like that)

 

[MagniKhan]

I've gotten a few of my parts for the project so far...



The handler, Vacuum pump, Gauges, Oxy/Acy torch, 2 disconnects, 100' 10/3 , 50' 12/2 wire, weather proof flexable conduit, various breakers and thermostat (though I may use the one on in the Co2 controller depending on suitability).



The compressor unit, refrigerant and line set arrives tomorrow.
Still waiting on Silver solder (15%), nitrogen tank, flow gauge.

After I get this unit installed and dialed in a bit I'll order and install the Co2 burner and controller.


Tonight I'm building the air handler stand and air box for the filters. I'm using uni-strut and all thread for the stand and some 1/2 plywood for the air box and to hold two 20x16x1 filters,also adding some rubber feet to the unit so it doesn't vibrate on the concrete floor.
I'll post the pics of some of the parts once I get them rough cut.

 

[MagniKhan]

Delay, windfall.....and some complications.

The compressor unit that was delivered was the wrong one,.... and will be replaced with a 16 SEER 2 stage unit.

This poses a few complications, but they are only minor one's.
Since I have a single stage air handler I will need to jump out a couple of terminals on the unit. The Y1 and Y2 will need to be jumped so as to keep the unit in the stage II configuration.
Last, but maybe lest, is the unit is a heat pump, so a conductor will have to be added to the reversing valve to keep it in cooling mode. Though I'm sure it's a small chance being that it will never change positions, it's one more part to go bad.

One bonus is that if the unit is over sized I can set it to stage I and it will produce about 60% of it total output. That my work out real well as I don't won't to move my veg box's just yet, AND it may help with humidity during the winter. I may just use a switch instead of a jumper.

I just received my 15% Silver Solder and I'm still waiting on the nitrogen tank and flow gauge. I also have to get a swagging tool to expand the copper tubing so I don't have to add couplers and such and can cut down on the total welds ( the more welds the more that can leak).