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Mini Split Line Installation, What Tools Do I Need?

Kevski

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Joined
Apr 19, 2010
Messages
62
Location
Seattle
Will be installing a Mitsubishi 24K mini split soon. I plan to hook it up with a prefab line set, (so no need to change the refrigerant charge or flare the lines) but don't know what tools to get to purge/evacuate the lines.

I have a Yellow Jacket R410A gauge/manifold set, a 3CFM vacuum pump that will pull 15 microns, and a nitrogen cylinder/regulator.

Do I need a digital vacuum gauge? How about adapter fittings?
 
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Milton Shaw

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Feb 11, 2011
Messages
4,835
To get all the moisture out the digital gauge is needed. Also it will show if you have any slight leaks in the system that would never show on a gauge set. Basically the digital gauge reads from 29" to a perfect vacuum at 0-50 microns where 29" is about 25,000 microns of pressure left. That said you are probably ok to just pull a vacuum and then let it set and see if any change in an hour or so. New systems fully factory sealed will not have moisture in them unless you let some in doing the work.
 

Git

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Joined
May 18, 2008
Messages
6,894
Location
S Cal
You can't get precharged linesets without an EPA certifitcation. At least not legally...

Tommy

The lineset isn't precharged - the unit is.

When I installed my Mr Slim I looked into buying the tools to evacuate the lineset and then pressure test with nitrogen. Somewhere I found the specs for what Mitsubishi requires - it was something like doing this three times, but I lost the link

In the end I contacted a local contractor who did the startup for me - and 'preserved' the warranty. Cost me $300 - which was about what the tools that I didn't have would cost.

Something to think about. Here is video that you may find helpfull
 
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walrus

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Joined
Nov 12, 2008
Messages
11,673
Location
Maine
Most split manufacturers recommend cutting off flares and reflaring and using their flare nuts
 

Git

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Joined
May 18, 2008
Messages
6,894
Location
S Cal
Most split manufacturers recommend cutting off flares and reflaring and using their flare nuts

That is a good point

I noticed that the flare nuts on my lineset were not up to the quality as the flare nuts that came on the Mr Slim. I had planned on only flaring the lines at one end, but I ended up flaring both because of this

Decent flaring tool with some nylog made it real easy

http://www.amazon.com/gp/product/B002SB5RMA/?tag=atomicindus08-20

http://www.amazon.com/gp/product/B008HOSQQQ/?tag=atomicindus08-20
 

crabjoe

Well-known member
Joined
Jul 15, 2012
Messages
197
Location
Ceciltucky, MD
That is a good point

I noticed that the flare nuts on my lineset were not up to the quality as the flare nuts that came on the Mr Slim. I had planned on only flaring the lines at one end, but I ended up flaring both because of this

Decent flaring tool with some nylog made it real easy

http://www.amazon.com/gp/product/B002SB5RMA/?tag=atomicindus08-20

http://www.amazon.com/gp/product/B008HOSQQQ/?tag=atomicindus08-20

I would love to try a set of these for flaring.

http://www.hvacbits.com/shop/flaring-spin/
 
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