Drawing a vacuum on a mini split?

[Guest 18340]

Sorry, didn't use a micron gauge. Just used a manifold gauge set for R410A.

 

[RedRain]

Any advice on hoses?

bring your pump to them

you normally need a adapter fitting for mini splits it a weird size

bring your vac pump and tell them the model of your mini split, they will hook u up

 

[Guest 18340]

If I'm not mistaken, the Mitsu's use 1/4" SAE. Some mini splits require an adapter, my Mitsu did not. I know you need an adapter with Sanyo models. I bought a Viot brand manifold gauge set for R410A and did not have to use an adapter.
Btw, here what the adapter's look like;http://kingersons.biz/productdetails.aspx?ProductID=447&categoryID=106

 

[driftersmokinjo]

I concur with RR on this 1 also As long as the pump you are looking at will pull at least 5 cfm and 2 stage you should be ok. another thing is you cant pull a vacuum for too long . Good luck and do as much research on the unit you chose as possible

Thanks guys! I think I'll look into the 3 ton units. I'd definitely rather be safe than sorry.

As far as the pumps go, I completely understand what you are saying Rain, about getting what you pay for. In my situation though, if it works once and I have to throw it away (probably won't be the case) then that's fine by me. I just really want to avoid having a tech come out to my location.

DunkyDunk, can I ask what size pump you went with off the Viot site? They have a lot of pumps and from the pictures they don't look like bad units.

I'm still up in the air about how I want to handle this, but I do have a few more weeks probably before I have to decide.

Thanks again guys...

 

[driftersmokinjo]

Any advice on hoses?

1/4 will do the job. Not sure what length your local supply house sells but I'm sure they have adapters to join hoses together and 6' hoses are common.

 

[RedRain]

1/4 will do the job. Not sure what length your local supply house sells but I'm sure they have adapters to join hoses together and 6' hoses are common.

they sell long hoses, all different sizes.

I am pretty sure all HVAC trade stores out here stocks 10ft hoses if I am not mistaken and longer. But they only sell to the trades, not the public.

GET FRESH VACUUM OIL FOR YOUR PUMP.

YOU NEED FRESH OIL FOR EVERY VACUUM. MOISTURE IS ABSORBED INTO THE OIL, GET FRESH OIL!!!!!

 

[MED-JACK]

well nitrogen is a dry gas and will assist in drawing moisture from inside the lineset. a vaccuum guage will do this as well.

if you are only pulling vacuum to -20 then you still have a ton of moisture in your lines. you should be pulling to -30 and it should hold there until you open the valves. you can test for leaks by just pulling vacuum but this will also show you how much moisture is present in the lines. if you are pulling vacuum and your guage is at -30, but when you close your guage it starts creeping back up, but you have pressure tested with nitrogen and know there are no leaks preset there is moisture in the lines. sometimes it can take hours for a pump to rid a system of moisture. i have 1/2" hoses to pull vacuum and a pump that is ported, polished and balanced and has 1/2" instead of the standard 1/4" inlet ports. my pump pulls vac like no bodys business. yellow jacket / ritchie ad JB make good stuff. pressure testing with nitrogen is used when brazing, cutting or joining pipe to ensure your welds are holding. but nitrogen will assist in ridding moisture from a line. without a micron guage, you wont really know what is going on.

there is alot of things that can go wrong if you dont know/ dont check / dont have the proper stuff. Just take your mini split to an HVAC shop and have them braze threaded quick connects into your mini split. this way you can disconnect, move and reinstall and service without calling a pro into service, recover your system. you cant handle the refrigerant or get holding tanks without a license. you can spend all the money on tools, but wihtout the proper knowledge of how a system works or the principles of refrigeration you are better off taking it to a pro. you make your system totally DIY and you know its done right!!!

mini splits are so expensive and picky and hard to get parts, why do people use them? a normal full sized condenser gives you unlimited repair part access, -50 cold weather working, power efficiency. You can just as easy have brass quick connect taps installed on a house ac and air handler. you also get more air flow and the ability to use a programmable thermostat with a real ac.

Any good sites on installing a normal central air unit???

Can you explain what your talking about the quick connects? So your saying they can make it DIY at your local HVAC place?

Thanks again RR.... keep the great info up...

 

[driftersmokinjo]

Any good sites on installing a normal central air unit???

Can you explain what your talking about the quick connects? So your saying they can make it DIY at your local HVAC place?

Thanks again RR.... keep the great info up...

don't think your gona get much help from rr on this 1. 410A is VERY DANGEROUS and there for it is not advisable to mess with it unless you know what you are dealing with. 410A can and will exceed 600psi I don't know if you have ever been hit with 600 psi of something that drops the temp of any thing it contacts in liquid form to around -58f . The out come won't be pretty I assure you. There is a reason it cost so much to have an HVAC guy do your work.Knowledge don't come cheap.

 

[RedRain]

Lol
R410a only goes 100 psi higher than r22. Max Operating is 350 psi where as r22 is 250

I have been busy as fuck and just haven't had time

I am all about sharing knowledge*

 

[driftersmokinjo]

Lol
R410a only goes 100 psi higher than r22. Max Operating is 350 psi where as r22 is 250

I have been busy as fuck and just haven't had time

I am all about sharing knowledge*

Are you saying 410 will only reach 350 and 22 only 250? What I meant about you helping him. With a normal split a/c system it is not designed as a diy thing and finding a sight with install help will be next to imposable. I am a member of 1 hvac forum and they have a pro section to keep the public out. You have to send a copy of your epa card to get in that part of the site. They will help common folk with simple stuff but not an install. Not intended as a jab at you Red.

 

[dunkydunk]

Mini splits are user friendly installs for anyone with decent screwdriver and wrench skills, many designs in Europe are made even easier with pressurized lines. They are a little harder to source in the U.S. RedRain seems to be saying an HVAC shop could make them for you. Which would be nice, I wish I had known that earlier.

If you were installing a more customized system where you were brazing lines over long runs and having to charge the system with refrigerant, etc., etc., then you damn well better have some chops as an HVAC Tech. But mini's are no big deal, they aren't exactly plug & play, but they're close.

 

[MED-JACK]

Thanks alot.... If you get the time i would like to hear from you..

 

[RedRain]

no worries buddy...I will be back on Wednesday

its not a big trade secret to properly braze on quick connect taps. its quite a common thing to do.

No worries smokinjodrifter, was just checkin in...sorry if i sounded like a jerk... I dont mind educating and sharing.

Yea its a $15,000-20,000 minimum fine when you vent refrigerant into the atmosphere in canada. Even with r410a, its terrible for the earth. But guess what, when pigs bust grows they dont even bother callin a tech out to recover and store the refrigerant. They punch holes in the condensers and vent all the gas out. WTF!!?

I'll snap some pics at work tomorrow for u MED-JACK. No problemo

 

[RedRain]

here are the quick connects....

with these you can disconnect, move, re-install all without losing refrigerant. This also allows you to bring in your unit to be serviced or fixed.

 

[MED-JACK]

here are the quick connects....

with these you can disconnect, move, re-install all without losing refrigerant. This also allows you to bring in your unit to be serviced or fixed.

Thanks alot buddy are those hard to get?

 

[RedRain]

any HVAC company should be able to do this for you, for the above mentioned reason. They are very common.

Do not go with silver quick connects as they rust, these brass ones are great.

 

[the_extremist]

Fuuuck

Fuuuck

Some crazy late season weather put this project off for a couple weeks, but we just finished the install yesterday.

So here's the deal. After everything we got it all installed, I hooked up the vac pump and gauge and the system couldn't draw down to a good vacuum. So I left the vac pump on for two hours and let the unit sit over night to see if it would hold vacuum. Woke up this morning and went and depressed the schrader valve on the service port. No hiss. So the system didn't hold a vacuum over night. I'm assuming that means I have a leak somewhere.

All my flare nuts are tightened very well so I'm at a loss for what it could be. I was very careful not to kink the line sets during installation. Is there a method of troubleshooting that would allow me to locate the leak and fix it?

 

[Guest 18340]

The flare faces where all round and shiny, yeah?

 

[the_extremist]

Yeah, they all looked fine to me. I'm really vexed right now and I don't know any safe HVAC guys. I have a bunch of huge monster bushes in veg too, lol. I can't bloom until the A/C is up and running.

I'm waiting on some advice before I pull it all back apart and start troubleshooting. I really hope I don't have to.

 

[driftersmokinjo]

Your best bet is to get a bottle of nitrogen and a regulator to leak test with. You have now pulled moisture into the system.
This is the exact reason us havc guys use nitrogen to leak test with BEFORE pulling a vacuum. It will be in your best interest at this point to invest in the nitrogen. after you get about 50psi you should be able to find the leak with a spray bottle of water with a tbl spoon of dish soap. You can get the nitrogen and regulator at any welding supply store.