mini split compressor problems

[guyyug]

New Sanyo mini split 12,000kbtu, installed myself. Pulled a vacuum with correct equipment/gauges for 30 min, held vacuum for 30min, no change in pressure, and released freon. Unit has worked perfectly and quietly for 1 month. Wasn't blowing cold anymore and noticed oil leaking from the flare nut on larger copper tubing connected to valve on condenser. Tightened it and SEEMS to have stopped leaking. Leaked probably half a thimble full of oil. Question: I know it leaked freon as well, but can I charge the unit w/out pulling vacuum on system again, and do I have to add oil back into it? (It holds 2.43lbs of freon) I do not want an A/C guy out so I need to do this myself.

If it is still leaking and I have a bad spot on the flarenut and have to remove and clean end, what is the procedure to do this? R-410a

 

[RedRain]

Well basically u are fucked

You didn't pull vac for long enough to see that your flare nut didn't seal. You didn't pressure test with nitrogen either

I have no idea where you are going to get r410a without a license. *Not to mention u need a recovery tank and recovery pump.*

 

[guyyug]

let's pretend that I have r-410a, can I just add some into the system or does a recovery and vacuum have to take place.

Grabbing the smaller lineset feels COLD still, the larger one, not as cold, but cool. Not that it matters, just fyi. But can I add freon, or do I have to pull vacuum again and/or add oil?

thanks for your time

 

[guyyug]

Also, I understand that there is a difference on what is SUPPOSE to be done and what is POSSIBLE to do. I just need to get this going, if I can keep from taking it out and putting another in it's place, that's what I want to do.

 

[guyyug]

Bad news, there is still a tiny leak at the flare nut. Can someone tell me if this is the correct way to go about fixing it:

Pump and reclaim refrigerant. remove flare and inspect repair flare fitting. with valves open from lineset into condenser, pull 50u vacuum. Check that it holds vacuum for 30 min. (I don't have nitrogen to go that route). Add freon in liquid form (upside down) If this is correct, do I weigh freon before and after to make sure that I have used 2.43lbs? My options are limited as to what I can do, what is the best route to take besides having technician on premise? (and just removing unit all together)

 

[RedRain]

this is what I would do

close liquid line tap (smaller line) watch suction line pressure as you hold contactor down to suck all refrigerant into compressor. Once suction pressure gets down around 10 psi, you can release contactor and start to close the suction line tap (larger line). Now the majority of the refrigerant is trapped in the condensor/compressor. Now recover the small amount of vapor left in the system.

or you recover the refrigerant as a liquid only through the red side of the gauge and through the smaller line. Once all the refrigerant has been transfered purge the pump to transfer the remaining refrigerant. Inspect or cut and braze lines closed. remove a shrader valve on one line and pump nitrogen through the lineset/evap and the excess nitro will leak from the valve where the shrader is removed. Then pressure test to 200psi for 3 hours. Pull vac to below 500 microns and -30. Hold vac overnight.

You can get a flaring tool and cut and re-flare the line and get a new brass flare nut, or acquire a tank of nitro,and braze the lines using couplers.

pulling vac is used to remove the atmosphere, moisture, oxygen from your system. it is also used to ensure no leaks are present. its a must to remove contamination.

 

[guyyug]

Awesome info. My condenser only has a valve on the larger side (low pressure side?). I have everything but the nitrogen, but I bet I can acquire that. Thanks again man.

Just curious, if a small leak occurred and was fixed before 1/4-1/2 of the refrigerant was released, would it be OK to simply add freon in liquid form, slowly, into the system? While compressor is running into the low pressure side? Or should it be done in vapor form? This looks handy, what do you think?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=400193523766&ssPageName=ADME:X:RTQ:US:1123

When I posted I knew RedRain would know the answer to this! Thanks again

 

[RedRain]

never add liquid to the compressor while its running to top off, add vapor.

liquid will cause the oil to froth inside the compressor

nice, I try to lend my knowledge when I can!

so just recover the refrigerant in a liquid form keep the blue (vapor)side closed, but you will see the vapor sides start to go down, as you pump liquid from the (red) side.

LOL fuck i wonder how they get away with selling that!!!

 

[Dammanfu]

Bad news, there is still a tiny leak at the flare nut. Can someone tell me if this is the correct way to go about fixing it:

Pump and reclaim refrigerant. remove flare and inspect repair flare fitting. with valves open from lineset into condenser, pull 50u vacuum. Check that it holds vacuum for 30 min. (I don't have nitrogen to go that route). Add freon in liquid form (upside down) If this is correct, do I weigh freon before and after to make sure that I have used 2.43lbs? My options are limited as to what I can do, what is the best route to take besides having technician on premise? (and just removing unit all together)

Sorry I didn't catch this eariler but this is the correct way to go about it R-410a is a blended refrig so you have to charge it liquid , recover /reclaim check your flare vacuum to 50 micron then weigh charge in (liquid) and with that much of a vacuum you will probably get the entire charge in without starting the unit if not start it and slowly crack the valve on your gauges to add more refrigerant that simple . No offence to the other poster but certian refrigerants have to be charged liquid R-410a being one of them

 

[guyyug]

OK, here is where I am now. I have tightened the sh!$ out of the nut, it has stopped leaking, now new oil, and spraying soapy water yields zero bubbles. The unit is cooling still, and grabbing the high pressure side line is VERY cold. I have read that the better name units over charge the compressors, SOMEWHAT and a small leak will not cause problems.

To check the charge, do I connect my gauge to the low pressure side with the unit running on high and expect to see 120lbs at ~75F ambient? If it is under that, then VERY slowly add refrigerant in liquid form until that pressure is reached? I have read that it should be between 120-150lbs? What do you think about this? I appreciate you guys helping me with this, it is frustrating not having all the knowledge and tools to troubleshoot more.

 

[gardenbug]

OK, here is where I am now. I have tightened the sh!$ out of the nut, it has stopped leaking, now new oil, and spraying soapy water yields zero bubbles. The unit is cooling still, and grabbing the high pressure side line is VERY cold. I have read that the better name units over charge the compressors, SOMEWHAT and a small leak will not cause problems.

To check the charge, do I connect my gauge to the low pressure side with the unit running on high and expect to see 120lbs at ~75F ambient? If it is under that, then VERY slowly add refrigerant in liquid form until that pressure is reached? I have read that it should be between 120-150lbs? What do you think about this? I appreciate you guys helping me with this, it is frustrating not having all the knowledge and tools to troubleshoot more.

As long as the suction side hasn't gone into a vacuum when running and pulled in air, you can add refrig to it.
Doing it the quick way, yes 110-120psi at 75f would work. Mini splits can be a bit harder to charged than a normal system, some run at slightly different pressures. There should be some kind of charging chart on the unit using ambient, approach, subcooling, or whatever method that manufacturer prefers.
Add 410 as liquid, just slowly.
Some old bottles need to be upside down, new don't it has a tube to the bottom to draw liquid, read the bottle it tells you.

As far as reflaring and stuff, usually that fitting is right on the compressor leaving no room to do that. Recover refrig, clean up fittings, vacuum, recharge. If the fitting looks messed up solder over it with hvac solder before adding refrig.

 

[DiscoBiscuit]

Bad news, there is still a tiny leak at the flare nut. Can someone tell me if this is the correct way to go about fixing it

You may already do this, if so please disregard

Can't help with the procedural methods but blue ptfe (teflon tape) wound clockwise two or three revolutions around male nipples should seal the joint.

You can use red ptfe with ~1/3 to 1/2 the amount. It's for threaded water fittings but the same ptfe.

Use your finger nail to seat the applied tape into the male thread valleys. This will keep the female thread ridges from excessively cutting the tape. Excess ptfe is supposed to squeeze away from the joint. Try not to over apply on 1/8" tube fittings.

 

[guyyug]

Update and question:

Low pressure side with unit on read 70psi. It was not blowing cold air. I added freon slowly until it read 115psi. Now the unit is blowing COLD air. The outside temp is 84F, does this seem like the best pressure to keep it (the best as in, the best I can do with what I have)? I do not want to overcharge the unit but wanted it working as efficient as I can get it...

 

[gardenbug]

Sounds about right, maybe slightly higher pressure depending on inside temperature.
Make sure the lines or evaporator coil inside isn't icing up, if it is you need more refrigerant (assuming airflow is good). If no icing then it will work. If you want to do it right follow the directions on the unit. Under one of the panels it will tell you how to charge it. Mini splits are strange sometimes, the only absolutely accurate way to charge them is to weigh in the refrigerant. Lots of them like to use the lineset as part of the condensor coil so it makes taking normal readings unreliable.
Also make sure the suction line (the bigger one) going to the compressor is somewhat cold, usually 40f-60f. The compressor should be warm/hot but not burning hot, if it is you need more refrig.