I am considering installing my Mini split system

[pinballlooking]

I have never used manifold gauges or vacuum pump. But the rest of the install looks like something I can handle.
Would this work.
Air Vacuum Pump with R134A and R12 Connectors
Vacuum Pump - AC Vacuum Pump w/ R134A & R12 Connectors


how about these gauges?
Yellow Jacket 42001 Series 41 Manifold 3 1/8" Gauges: Amazon.com: Industrial & Scientific

how about this gauge or do you recommend a different gauge?
Fieldpiece SVG3 Digital Micron Gauge (Vacuum Gauge)
Fieldpiece SVG3 Easy View Vacuum Gauge - at the Test Equipment Depot

[NiHaoMike]

That vacuum pump is good for vacuum bagging, but no good for HVAC work. A freezer compressor would be far superior to that. But for about $150 or so, you can get a reasonably good two stage.

For some reason, automotive gauges and residential/commercial gauges are different. You should be able to get a reasonable deal at a local HVAC store. (I got my pair of Yellow Jacket gauges for under $50 at a local store a few years back.)

A micron gauge is not a requirement, but it can be very helpful. For a one off, doing a pressure test followed by a triple evac gets it done.

You do need some way to purge (if you need to braze) and pressure test, which can be done with nitrogen or CO2. (Propane can be used for purging, but only for the outdoor connections.)

Also note that a common propane torch will not work for brazing. MAPP gas works, but the good stuff isn't made anymore. Nowadays, either oxy-propane or air-acetylene works great. (So does oxy-acetylene, but it's especially easy to overheat the braze with it...) If you wait long enough, you might be able to find an oxygen concentrator for cheap on Craigslist.

[WyrTwister]

Originally Posted by NiHaoMike

That vacuum pump is good for vacuum bagging, but no good for HVAC work. A freezer compressor would be far superior to that. But for about $150 or so, you can get a reasonably good two stage.

For some reason, automotive gauges and residential/commercial gauges are different. You should be able to get a reasonable deal at a local HVAC store. (I got my pair of Yellow Jacket gauges for under $50 at a local store a few years back.)

A micron gauge is not a requirement, but it can be very helpful. For a one off, doing a pressure test followed by a triple evac gets it done.

You do need some way to purge (if you need to braze) and pressure test, which can be done with nitrogen or CO2. (Propane can be used for purging, but only for the outdoor connections.)

Also note that a common propane torch will not work for brazing. MAPP gas works, but the good stuff isn't made anymore. Nowadays, either oxy-propane or air-acetylene works great. (So does oxy-acetylene, but it's especially easy to overheat the braze with it...) If you wait long enough, you might be able to find an oxygen concentrator for cheap on Craigslist.

I have read multiple warnings about brazing mini splits . Most recommendations were not to . If you do , the recommendation was a gentle flow of dry nitrogen though the lines , to keep air out & prevent oxidation / scale from forming inside the copper , at the point being heated . It was said , due to the small clearances in a small system such as a mini split , they are especially susceptible to such trash stopping stuff up .

My mini split came with flare fittings , as does most of the units I have read about . While I am a little suspicious about leaks with flare fittings , it solves the brazing issue .

I bought metric flare nut / tubing wrenches , a 3/8" drive torque wrench and straight and flare nut 3/8" drive " crows feet " . At Harbor freight .

I bought a small container of Nylog Blue for automotive gasket / o-ring use . Also found a recommendation to use it on mini split flare fittings . It is a slimy , slick , sticky substance . About the consistency of snot . Seems to work ?

I have not found much info on the POE oil used in mini splits ( I have used POE oil in a R12 -> R134a conversion on a car ) . Any one with a catalog # and brand , or a specification ( including viscosity ) , please send the info to me .

God bless
Wyr

[pinballlooking]

Originally Posted by WyrTwister

I bought metric flare nut / tubing wrenches , a 3/8" drive torque wrench and straight and flare nut 3/8" drive " crows feet " . At Harbor freight .

I bought a small container of Nylog Blue for automotive gasket / o-ring use . Also found a recommendation to use it on mini split flare fittings . It is a slimy , slick , sticky substance . About the consistency of snot . Seems to work ?

God bless
Wyr

I bought this same set from Harbor Freight and a bottle of Nylog Blue.

[WyrTwister]

Originally Posted by pinballlooking

I bought this same set from Harbor Freight and a bottle of Nylog Blue.

I ordered the Nylog Blue off the internet . Can not remember where ?

Last used it helping work on my cousin's car A/C .

Seems to work well .

Think they make Nylog Red for R12 systems . Maybe for R22 , also ? Both use mineral oil , but I do not know if they are the same mineral oil ?

God bless
Wyr

[BMR]

Originally Posted by pinballlooking

I bought this same set from Harbor Freight.

Just a heads up that you may find you need fractional, not metric flare and/or crow's foot wrenches. Check your equipment and lineset when you get them.

[WyrTwister]

Originally Posted by BMR

Just a heads up that you may find you need fractional, not metric flare and/or crow's foot wrenches. Check your equipment and lineset when you get them.

Best I remember , mine were metric ? Used the crows foot on the 3/8" torque wrench . Set at 03:00 o'clock or 09: 00 o'clock position ( perpendicular to the handle of the torque wrench ) .

I read that would give the most accurate reading with such a set up . Used a flare nit wrench , for backup , on the small line .

On the big line , best I remember , I did not have a crows foot large enough for the big flare nut . I used the crows foot and torque wrench on the " body " of the fitting and a big crescent wrench on the big flare nut .

The paper instructions had a typo on the torque specs . I had downloaded a pdf file of the instructions . They had the correct info .

So , if the numbers do not sound right , double check .

My outdoor unit had a plastic fitting to go on the bottom . Instructions said this is a drain for water , when the HP went into defrost and melted frost . Some / most of the water may run down inside the metal housing .

I bought a few feed of hose to go on the plastic fitting , but the fitting stuck down too far to allow the unit to set level , on the concrete .

Another trip to the store & bought 8' of 4" x 4" treated post . I cut 2 blocks for the " feet " of the out door unit to set on & screwed the " feet " to the 4" x 4" blocks . This gave plenty of clearance for the drain fitting and hose .

MiniSplitCondensor07-04-2013_zps7dfe4994.jpg Photo by WyrTwister | Photobucket

God bless
Wyr

[pinballlooking]

Ok maybe this pump
3 CFM Two Stage Vacuum Pump
Air Conditioning Vacuum Pump - Two Stage, 3 CFM
I have a 25% off coupon.

[mejunkhound]

Vacuum 'pump' you show is worthless, do not throw even $15 down a rathole. You need something that will pull down to under 1 Torr, 500 microns preferred. (10 Pa ,5 Pa )
Cheapest one I saw right off on ebay is:

Single Stage 3CFM 1 4HP Rotary Vane Vacuum Pump HVAC Air AC A C R410A R134a | eBay

micron gauge is good, but you can probably find a used analog one for less $$. Be aware that if you have any type of leak, the micron gauge will always show maximum even though with a small leak the gauge set will show 30" of vacuum. It will also take a few minutes to pump down until the vac gauge shows anything.

gauge sets per se are OK, but you will need adapters for R134 to R410A connections, and also for sae 5/16 to 1/4 interconnections.

Would be good to get a nitrogen bottle and regulator to do preliminary pressure testing also.

Don't forget to get a small quantity of POE oil to lube ALL surfaces of the flares before torqueing.

I prefer to pull vacuum for 15-20 min, put dry nitrogen into system at 400 psi and turn off all gauges and let sit overnight. Pressure in the morning should read the 'same' as the previous day - don't forget to calculate temperature effect on pressure. Then pull 500 micron or lower vacuum and hold for a few hours (I do overnight just to make sure)

Then just crack slightly open the valves on the outdoor unit, just enough to show a few psi positive pressure - and ONLY then remove the gauge hoses.
Now open the outdoor unit valves fully and cap the ports.

Good luck.

PS: ditto on Mike's comments. I use 15% Ag silphos for brazing, NEVER try to 'just get by' with soldered refrigerant connections.

[NiHaoMike]

An analog vacuum gauge would be worthless for HVAC, except the exotic sealed units that actually measure low vacuums. (But those probably won't be cheap...)

The second vacuum pump you linked is great.

Don't bother with POE oil, just get a small bottle of Nylog Blue. Very cheap and use it on every flared connection.

As for the best brazing rod to use, Dynaflow is cheap but still easy to work with.

You'll want to leave your gauges connected for the initial power up for checking pressures. Once the third stage of the triple evac is over, close off the gauge valves and open the suction side service valve slowly. (Do it too quickly and the oil in the compressor might foam up and get sucked out of the crankcase. Unlikely but possible.) Then open the liquid line valve and start it all up.

You'll also want a torque wrench (and a set of open ended sockets) for flare connections and a thermometer for checking superheat/subcooling.