Pioneer Mini-split flare torque questions.

[motterpaul]

I have a registered WYS012AMFI19RL 12,000 BTU Pioneer mini-split that after two good years has suddenly lost coolant. I want to reflare and reload. I need to buy the right-sized torque wrench and wrench jaws for the flares.

The 1/4"-1/2" lineset on that unit correlates to 5/8" and 15/16" tool size needed for the flare nuts. The torque recommendations in the installation manual specifies N.cm measurements for the amount of torque. So for Newton-meters I can just divide by 100. To me, that means 45 N.m, which I can also convert to foot-pounds.

Can someone please give me specific information on what will be the right torque wrenches to buy? How are they commonly described and/or listed (in C-nm, N.m, or Fp? I mean N.cm seems pretty uncommon where I have looked. Maybe someone who is more familiar with torques can give me some clarity on what to look for?

ALSO: What is the best way to detect where a leak has occurred. I know one is to look for oil, but my leak was so slow I do not see any oil. What should that oil look like? Is it slippery, and not sticky (my lines are sticky but I assume that is from the foam cover). I also have bubbles and a somewhat cheap leak detector to use (but it works when tested on larger amounts of R410a)

 

[jjrbus]

One thing I noticed when trying to gather the knowledge needed was some people use a flair gauge, a simple go no go gauge. Seems to be idiot proof? Looking for one for sale I came across a Daikin mini split install kit for very reasonable price and included torque wrenches. https://cdn.daikincloud.io/PIM/Assets/Documents/PB-DACA - Daikin Tool Kit Detail.pdf

 

[metlmunchr]

The current Pioneer installation manual gives the torque values in both N-cm and ft-lb. The original flares on the Pioneer tubing package are far too large. IMO, this causes the pressure on the joints to be too low for reliable sealing. Torque on the nut creates a clamping force. Force divided by the area of the flare gives the pressure on the joint. As a rough guess, I'd say the flares on my Pioneer tubing package were twice the area of a proper flare, and that results in half the pressure on the joint as compared to the pressure resulting from the same torque applied to a proper sized flare.

Pioneer's installation manual gives the proper height to set the tube above the face of the flare block. These dimensions will produce a proper flare.

A 3/8 torque wrench will cover the needed range for both sizes of lines. I already had a set of crowfoot line wrench sockets that covered flare nut hex sizes up thru 7/8", and I don't recall having to purchase a 15/16 socket for the 1/2" tube nut. Don't know if you've actually measured the larger nut, but it would be worthwhile as the parts are all imported and don't necessarily follow all SAE standards for dimensions. If you don't have line wrench sockets, O'Reilly Auto has a set for $29 that covers hex sizes from 3/8 thru 7/8. The quality is excellent, and the full set costs about the same as a single socket from many other brands. The brand is Power Torque, which is O'Reilly's house brand.

When using a crowfoot socket on a torque wrench, you have to calculate the allowance for the fact that the torque is being applied at a different point than the centerline of a standard socket. Otherwise, your actual applied torque will be somewhat higher than the wrench reading. The reduction is the ratio of the length from the square on the wrench to the pivot point on the handle divided by the length from the center of the crowfoot to the pivot point on the handle.

In heating mode, the indoor unit becomes the condenser and the line set is subject to the highest pressures during that mode. Because of this, you can't just squirt a little refrigerant in the lines and get adequate pressure for leak checking. You have to have nitrogen or some other non reactive gas source at a high pressure to get sufficient pressure for reliable testing. I've got an electronic leak detector, but I still find soap bubbles the most reliable method for leak checking. I pressurized mine at 450 psi for testing. I used argon CO2 mix because I had it for mig welding and wasn't interested in buying a nitrogen cylinder.

Obviously, you'll have to have a vacuum pump to evacuate the system prior to charging and a refrigerant scale to weigh in the charge as you can't reliably charge a mini split via pressures.