We are talking mini split right, they don’t usually have thermostatic expansion valves in the indoor units, if other equipment adding service ports comes to mind. If you are connecting it anyway, you don’t have to flow nitrogen through the expansion valve just the point you are brazing.
On a traditional US split system, you're right the expansion valve is right before the evaporator. When using a TXV, it has to be because the temperature sensing bulb has to be attached right near the evaporator. On minisplits, they use an electronic expansion valve (EEV). It doesn't have a temperature bulb attached to it. So they put it inside the outside unit to keep the head units simpler and cheaper to make. That's why on a minisplit, all the copper lines have to be fully insulated. On a traditional US split system, the liquid line doesn't have to insulated due to the expansion valve being in the air handler.
This is also why you don't use sub-cooling to determine refrigerant charge level in a minisplit like you do in a traditional US split system. And therefore why they don't put high and low pressure service ports on minisplit systems.
Yes I understand that I was replying to someone else who said brazing a mini split was a good way to avoid flare joint leaking. The one I installed I used nylog on the joints seemed to work okay I don't have a nitrogen bottle to pressure test it. Did hold a vacuum for 24 hours I used a torque wrench on the fittings. Unfortunately do to the E0 error not able to even turn it on yet waiting on Chinese support still about 6am Monday maybe in a few hours they will reply.
I must have missed it.
I used a poor man's torque wrench in a form of spring scale (one you weight stuff by hanging). I "calibrated" my scale with a real torque wrench (I just don't have the ends that fit HVAC fittings) and I "torqued" it like that...
Wow, that's a bummer. I'm sorry to hear that. Here I wouldn't get any warranty by doing a DIY install. But I'm getting a personal HVAC certificate hopefully next month so I'll be able to sign my own paperwork and get warranty etc.
Here state contractors license boards require 2 years of verifiable experience working under someone else's license number before your allowed to even take the contractors test to get a license. I noticed on Diakin registration form they want the contractors license number.
Things have changed I had to have years worth of hours on the job and the test was no piece of cake either, but that was over 25 years ago. We used to have good service technicians as well, now they just rely on error codes and have absolutely no idea how to troubleshoot without a computer telling them what’s wrong and how to fix it.
I'm in Europe (Poland). Here there are two kinds of "entry level" licenses. One is a so called personal license. No experience necessary, but you can't have a conviction for "crimes against the environment" (as funny as it sounds). You just do a days course and pass a theory followed by a practical exam. I'm told its not difficult if you prepare. They even do them on weekends. This gives you ability to buy refrigerant gasses as well as to do installs/servicing for yourself or an employer. If you want to do it for others you need a business license which is a similar procedure (a course followed by a theory+practical exam). You also need to have various equipment for a business license (recovery machine, recovery bottles, leak detection stuff etc). Someone with a personal cert can just hire the kit.
I can have 22 cylinders of R32 delivered tomorrow, so it is available in the PNW.
The expansion valve in a mini split is in the outside unit, and 90% of the time it’s an eev.
Somewhere I heard the hole that goes trough the wall (indoor to outdoor) should be at a downward angle. Is this only because of the condensate tube or other ones too?
It's for the wire dumb dumb, so that the electrons slide the right way
I guess in a lot of situations that would make sense. Especially if going through a thick wall. But it would be as much for the condensate flow as you point out.
