do I open both hex ports before pressure testing a mini-split with no refrigerant in it?

[hazehendricks]

do I open both hex ports before pressure testing a mini-split with no refrigerant in it?

 

[hazehendricks]

I was told it has no r410a in it. I installed it with new line set, replaced the 8 year old Schroeder valves, bought refrigerant scale, vacuum pump, nitrogen w 600 psig regulator , 10lb r410a, manifold gauges , temp sensor for lines, 5/16 adaptor , 2 vacuum rated valve core removal tools w/ball valves..etc.....I'm just wanting to better understand the process if the system has no r410a in it.

 

[Terry D]

If you are for sure there is no freon in it, then yes, you would open both ports to pressure test it. I would put 300 psi of nitrogen in it, pressure test it for 30 to 45 minutes. Spray leak detector on your flares and check for bubbles.

Vac it down to 200 microns. Close the valves on your core removal tool for 30 to 45 minutes, as long as it doesn't raise above 500 microns, then you are good to go. Weigh in you charge per the name plate

 

[rkevins]

if no refrigerant, yes you need to evacuate the entire system to get all the moisture out.

 

[Terry D]

This guy is pretty good

 

[hazehendricks]

If you are for sure there is no freon in it, then yes, you would open both ports to pressure test it. I would put 300 psi of nitrogen in it, pressure test it for 30 to 45 minutes. Spray leak detector on your flares and check for bubbles.

Vac it down to 200 microns. Close the valves on your core removal tool for 30 to 45 minutes, as long as it doesn't raise above 500 microns, then you are good to go. Weigh in you charge per the name plate

yes , the hex ports open with no sign of charge... the unit is 7 yrs old-senville 1200btu Leto version . I was thinking about old, possibly trapped r410a that could have been contaminated .....should I get a magnet and use it to manually open up the EEV all the way before test and vacuum. Or will doing a triple evacuation using nitrogen be a good choice seeing as I don't know the units history and I'm concerned about making sure it is free of contaminants. Also is there any other area where contamination could be trapped. I just don't want a system that's not clean, dry and tight.
Thanks for any advise.

 

[Terry D]

If the condenser was stored with the valves closed, I wouldn't worry about anything getting is there. Were the lines taped closed on the evaporator ? Someone else might be able to answer your question better on the EEV. I personally would not think you would have to manually open it, but could ne wrong. I have only installed brand new mini splits, never reinstalled a used one. A triple evacuation would not hurt. Just remember the factory charge on the name plate is based on the length of lineset that originally came with it. Anything longer and you will have to adjust the charge. If you don't have the owners manual, you should be able to find it on line

 

[Milton Shaw]

If you haven't done the repairs yet, you ought to install new dryers on the questionable liquid and suction line. Make sure you point them in the right directions and add the additional charge required for them. If this is a heat pump unit make sure the dryers are heat pump rated. Cheap insurance to make sure all the moisture/trash is out of the systems. This is just as important as pulling a vacuum into the microns range. From what I have seen on EEV's a magnet will not open them, only a stepper coil magnet will turn them open.