Drawing a vacuum on a mini split?

[Holdin']

You either have bad fittings, or a bad micron gauge. Also be very aware that poor quality copper can make successful flare fittings NOT 100% even for the experienced. Also what type of vacuum pump are you using? I don't think I noticed you saying you got a new one...

For comparison, I am a full time HVAC service tech, formally an installer, I have installed hundreds of these things, and as a technician have repaired many poor flare fittings. But anyway, I have a 7 cfm vacuum pump, with a dependable micron gauge, and say I suck down a 2 zone system with say 50 ft worth of lineset, I should be down to 300 microns within 30-45 minutes.

Over the three hour period you had the pump on, I'm also curious what kind of readings you were getting on the micron gauge.

And for the record, I work for a HVAC company in WA state. We have done work for patients a couple of times... But most companies don't want much to do with DIY, and if they do, they charge ridiculous prices. There's a good handful of weed smoking, tight lipped, understanding technicians out there who will do work on the side. If you can use a professional, it is most recommended, as I would hate to see you trying to do a DIY compressor replacement in a couple of years.

 

[the_extremist]

Yeah, I think I found one of those guys today. He's coming by tomorrow to check it out.

I'm all for fucking around and learning things on my own when it comes to most things, but I'm behind schedule now and I know fuck all about HVAC work. I'll let you all know what the problem is.

 

[RedRain]

hey the_extremist

good to hear you have some help on your way. let us know how it works out for you.

I normally braze or use quick connects, so I dont ever use the flares so I cant comment on crappy flares, but it doesn't surprise me.

the tech should figure it out pretty quick with 200psi of nitro.

Holdin'- he is using a cheap no name, but very recommended pump by some members here

 

[the_extremist]

So it turns out my micron gauge was no good. The guy that came to help me out drew vacuum and then charged the system. His gauges read fine. No leaks, held pressure under load for over an hour.

I'm so happy to have this thing up and running. I can't say enough good things about the Mr Slim. This thing is so quiet that it barely even sounds like it's running. And they blow ice cold air.

Mucho thanks to everyone who helped me out with advice. Reps for you.

 

[RedRain]

ya i was wondering.

i paid $900 for my digital micron gauge!!

you can never waste money on quality tools!!

good to hear!

 

[Bubbly Terps]

Ya so u installed a simple mini split yourself do u want a gold star? They are simple enough for anyone to so but when u have a problem that's when u need a professional because u don't have the knowledge or the tools to solve an simple issue that a pro could fix.

If u don't know to vac down lines or quick connects after brazing then u don't know enough about AC work.

I also mentioned to take it to a pro to have them braze on quick connects, so the company would have already pressure tested , and pulled vac.

U are a tool buddy !!

LOL typical attitude from an HVAC "pro" on a cannabis board...this one must have gotten banned for forgetting to pay his "advertising" bribes? I love how he assumes that you'd take your indoor + outdoor units for your splits, along with your linesets, TO a professional in order to get QUICK CONNECTS brazed on. That'll make things simpler, I'll just transport my house piece by piece via wide load truck. Yep, they would have pressure tested, because all your unnecessary work has now necessitated the use of pure nitrogen to prevent oxidation! Genius, but your attempt to lure growers into giving you more money has failed. Mini-splits for all!

 

[gypsya]

vacuum not done right...can we try again?

vacuum not done right...can we try again?

Hi,

My husband installed a unit similar to this one:

http://www.homedepot.com/p/Celiera-...ct-5-_-203013144-_-203369166-_-N#.UhKNUtJ4yVo

But, it didn't work right when all set up. After reading the instructions again, he saw there were discrepancies in how to draw the vacuum on the unit. He thinks he followed the directions that left out a step.

The unit ran for about 3-4 hours, possibly without the vacuum done properly, resulting in no cool air. Can he try again to do the vacuum, using the other instructions that include a different step, or have we done damage to the machine already????

Thanks for any advice.

 

[Puscifer]

What step did he leave out?
And did he open the service valves to release the freon into the lines?

 

[gypsya]

One set of instructions said open the liquid valve 1/4 turn, wait 10 sec then press the service valve for 2 seconds, then fully open the liquid valve.

The other set of instructions said open the liquid valve 1/4 turn, wait 10 and then CLOSE it (and the rest of the instructions were the same).

He followed the first instructions, which now we see are the "purging" instructions. The other is the bleeding. The instructions said the purging is the only thing that's needed.

If he did step one and it ran for a few hours and didn't get cold, does that mean he did it wrong or that we ruined the machine by letting it run?

 

[Puscifer]

Did he open the gas valve?
Also, when he pressed the service valve for 2 seconds, did freon spray out?

 

[gypsya]

He must have done something right to fix it, in between me texting and relaying your questions, because now it's working. It's pumping out great and it's really cool! Yay! Thanks for your help.

 

[the gnome]

good info in this thread,
i'm installing a 32.5btu mitsu-mr slim in the next few weeks.
i kno an hvac guy(doesn't kno what I'll be doing) and want him to possibly vac the lines and make sure its doing its thing.
I'll get everything installed where it needs to be and do the elec hooks ups.
he will only hook up the line set, vac and make sure its good to go.

I really prefer no one knows where this is being installed for security reasons.
he may say or wonder why a 32.5K btu for a 14x 23ft room
also depending what he's going to charge I may buy the vac pump, gauges and micron tester.
if i do everything what brand size vac pump, gauges and testers do i need to complete the install, i read earlier in this post don't get the vac pumps from harbor freight.

i do kno a auto guy the did the ac leak fix on my truck,
he has a vac pump on a dolly to check for leaks etc etc.
he said i could use it on a weekend.
would this vac pump work?
or is there a rating for a minimum size pump??

 

[Puscifer]

A 3 cfm or higher will do the job. Also, it needs to be a two stage pump. Shop around online and you can get a good one for 'round $200.
A Supco digital micron gauge is decent for the price. And a manifold gauge set with hoses can be had for less than $100. Make sure the gauge set is for R410!
Don't know if your buddies vac pump will work, ask him if it's a two stage.

 

[the gnome]

A 3 cfm or higher will do the job. Also, it needs to be a two stage pump. Shop around online and you can get a good one for 'round $200.
A Supco digital micron gauge is decent for the price. And a manifold gauge set with hoses can be had for less than $100. Make sure the gauge set is for R410!
Don't know if your buddies vac pump will work, ask him if it's a two stage.

talked to my auto guy and he said it wouldn't work, cars don't use R-410 and the fittings won't connect to my mini-split.
the hvac guy will look at it this afternoon and give me a price so i'll decide then.

thanks for the heads up on the pump/equipment puscifer


edited:
well talked to the Hvac fella, if all he has to do is connect the lines, vac and start it up its gonna cost me $75 for initial visit for the 1st hour and $50 an hour after that.
so about 2 hrs, were looking at $125.
I think that's adeal!