# Brand new mini split having issues



## WyrTwister (Jul 22, 2013)

The 2 mini splits we installed at our home had a short length of small and large copper refrigeration lines attached to the indoor unit . The remainder of the 2 lines attached there using flares on the copper lines and flare nuts . These flare nuts need to be torqued to the specified amount . Same where the 2 lines attach at the condenser unit .

Did you examine the connections at all 4 flare nuts ? This would involve opening up the insulation at the connection to the indoor unit piping .

A refrigeration gauge needs to be connected to the unit . Mine have only one fitting to attach a hose , at the service fitting for the large line .

I suspect you either have a leak ( look for the presence of leaked refrigeration oil ) .

I hope your friend did not connect the lines by brazing / silver soldering them . This is discouraged . If it has to be done , dry nitrogen must be flowed through the lines while brazing , silver soldering .

If you have a leak , the refrigerant needs to be reclaimed and stored . Fix the leak . Pressure test it . Vacuum the system . Weigh in the refrigerant & if your lines are shorter than the " standard amount " for your system . Subtracting or adding the specified amount , per foot , for the discrepancy in the length of the line set .

Some will criticize , but I use Nylog Blue on all the sealing surfaces of the flare fittings .

I suspect you will need R410a refrigerant . Mine do .

God bless
Wyr


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## Bitters (May 28, 2014)

Sounds like a restriction. Make sure the high side service valve is opened all the way.


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## WyrTwister (Jul 22, 2013)

*Oops .*



WyrTwister said:


> The 2 mini splits we installed at our home had a short length of small and large copper refrigeration lines attached to the indoor unit . The remainder of the 2 lines attached there using flares on the copper lines and flare nuts . These flare nuts need to be torqued to the specified amount . Same where the 2 lines attach at the condenser unit .
> 
> Did you examine the connections at all 4 flare nuts ? This would involve opening up the insulation at the connection to the indoor unit piping .
> 
> ...


 Sorry for the oops . Mine use R410a . Mine are OK & do not , to my knowledge , need refrigerant .

God bless
Wyr


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## roughneck (Nov 28, 2014)

Is their refrigerant in the system? How many microns did the system get evacuated to? What was the test pressure during the leak check, and how long did it hold?


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## supers05 (May 23, 2015)

Both lines will be low pressure on mini splits. Sounds like a leak. 

Cheers!


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## WyrTwister (Jul 22, 2013)

My understanding is the expansion device on a MS is inside the condenser unit . So , in cooling mode , I can see where the small line might not be as high pressure as in a traditional split system . But It seems to me it would probably be higher than at the large line ?

All this , being in cooling cycle .

My understanding is in heat mode , the high pressure gas flows from the condenser unit to the indoor unit via the large line ? So , in those circumstances , would the large line be high pressure ?

God bless
Wyr


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## TraumaMedic (Aug 22, 2015)

Thanks for the fast responses! He didn't use nitrogen but he deep vacuumed the unit down to around 150 microns if I remember right. The vacuum was held for roughly 30 minutes with no changes so we assumed that the system was free of leaks. There is refrigerant in the system unless it leaked out but there is no oil, bubbles or any sign of a leak at any of the connections. 

One weird thing is that in heating mode the large pipe gets hot and the small one is ambient to the touch. However, there is NO heat coming out of the indoor unit. So it seems like the condenser is working but the indoor unit is not. Anyone have any idea why this is happening?


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## roughneck (Nov 28, 2014)

Was any brazing done?


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## WyrTwister (Jul 22, 2013)

I have seen an automotive system where it would hold a deep vacuum for 2 days . But when it was charged with R134a , in 2 days it had leaked down to the point where it had basically quit cooling .

In my mind , if it will not hold vacuum , it certainly is not going to hold pressure . But if it does hold vacuum , it is not necessarily going to hold pressure .

And yes , brazing / silver soldering is contraindicated for MS's .

Has anyone hooked gauges up to the unit ?

God bless
Wyr


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## Ron6519 (Mar 28, 2007)

This wasn't installed correctly. Hire someone who will.


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## TraumaMedic (Aug 22, 2015)

No brazing was done- everything is flare and nut. The only gauge that has been hooked up to it was a blue low side gauge when he was vacuuming it out. The thing looked something like this.

http://www.amazon.com/One-Manifold-...d=1440453059&sr=8-2&keywords=mini+split+gauge

I can't afford to hire someone for another 3 weeks


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## WyrTwister (Jul 22, 2013)

Stick that gauge on it , while it is running & see wgat the pressure is .

God bless
Wyr


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## supers05 (May 23, 2015)

The 2 lines will be within 2psi of each other, or we'd say that it has a restriction. On most mini splits, there is only one service port however, so no easy way to check. It doesn't matter if it's in heating or cooling mode. (The OP only mentioned cooling)

The smaller line in heating mode should be slightly warmer then room temp, or something is wrong. If the air from the inside coil is not at least warm, (in these temps it should be hot,) then again, I still think it's low on refrigerant. 

Just to be on the safe side, push the "turbo" mode or similar button on the remote. After 30sec you should hear the compressor ramp up to 100%. (it may already be there so you'll have to listen on startup too.) It usually takes about 30-60sec to fully ramp up. You should be able to hear it from a ft or 2 away. Check the amp draw then, and report back, along with the fla/rla on the name plate. 

Some times you will only have a leak when it's vibrating, or under the highest run pressures. I've also seen systems hold a vacuum and still leak under pressure. (and vise versa) There's a chance that it's seeping through the u bends on one of the coils. You'll need a leak detector to know though, it won't make bubbles big enough. 

Cheers!


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## TraumaMedic (Aug 22, 2015)

I checked the pressures on the low side and it is fluctuating anywhere from 58 to 66 PSI. Before doing this I found that the low side's (shrader?) valve was busted and the pin wasn't sitting right against my gauges. This means that when I pulled my vacuum I was pulling against the hose only as the valve wasn't actually open... So the unit was never vac'ed out after all, does this mean I'm totally screwed? I am borrowing an amp meter this week and will let you know the results.

Thanks again for all your guys' time.


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## WyrTwister (Jul 22, 2013)

Replace the Schrader valve now .

I would purge it with dry nitrogen and try to flush out the air and some of the water .

Vacuum it down now . 

Leave the vacuum on it for a long , long time . Observe the vacuum level you get to on the micron gauge .

Then pressure test it with dry nitrogen .

Vacuum it down again .

Weigh in the proper amount of refrigerant . Liquid , if it is R410a .

All during this , try not to loose much oil .

God bless
Wyr


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## roughneck (Nov 28, 2014)

The system can be destroyed with noncondensibles inside the circuit.


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## yuri (Nov 29, 2008)

1) Replace the schrader valve

2) Pressure test it with nitrogen to see if you have leaks on your flare connections and use 200 psi or more and make sure it holds. Remove the hose quick and make sure the schraeder works. Should have a step down pressure regulator on your nitrogen tank and a dual gauge set that can read high pressure ( conventional refrigeration/HVAC gauges ). Soap does not work well as it runs off quick. Pros use Nu Calgon gas leak detector soap as it clings and shows VERY VERY tiny bubbles that soap does not. Check the max pressure rating for that unit as it may be below 200 for the low pressure side. On split resi systems we can go that high.

3) Pull a 500 micron vacuum with a micron gauge

4) Weigh in the freon with a scale.

If you cannot do all this hire a Pro.

http://www.nucalgon.com/products/gas-leak-detectors


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## TraumaMedic (Aug 22, 2015)

So the refrigerant has to come out then? Or can the system be pressurized in a way where the refrigerant goes back to where it came from the factory? I can do the vacuum and nitrogen part, but since I can't get refrigerant myself is there a way to reclaim and reuse it? Or am I at a point where I can no longer do this myself and have to call an HVAC guy out? Thanks again for the quick replies and time.


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## yuri (Nov 29, 2008)

It now has air mixed with it. Legally it is supposed to be recovered and destroyed. Not sure everyone does that. You may be able to buy freon if you take the proper EPA course and get a license. I am in Canada so the other posters here can help you with that.

If you hire someone you must tell him it may have air with it or he can get in BIG trouble if he sends a mixture back for recycling. Very expensive to destroy it.


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## roughneck (Nov 28, 2014)

It must be reclaimed and disposed of. Virgin refrigerant must be used for a recharge.


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## TraumaMedic (Aug 22, 2015)

Awesome, I am glad I know whats wrong now! Thanks so much everyone, you really helped me out on this project. :thumbsup:


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## WyrTwister (Jul 22, 2013)

I may be wrong , but technically , in the USA , you may be able to buy R410a ( which is probably what you have ) with out an EPA card . You can buy R134a .

But , I have an EPA card , so , it is a non issue for me . If I can help you with that , PM me .

The issue is air is now mixed with your refrigerant . You can not re-use it , or you will be back in the same boat .

Best of my knowledge , there is no simple / easy to remove the air from the refrigerant .

They make a device to change out Schrader valves with out dumping the refrigerant . I bought one years ago to change out the Schrader valves on my R22 system .

God bless
Wyr


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## Bob Sanders (Nov 10, 2013)

WyrTwister said:


> I may be wrong , but technically , in the USA , you may be able to buy R410a ( which is probably what you have ) with out an EPA card . You can buy R134a .


Correct. No epa card is required to purchase r134 or 410 in the usa. I bought a 28 ounce top up bottle there without issue.


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## WyrTwister (Jul 22, 2013)

Much more cost effective to buy it by the jug . 

Do not know about now , but Sam's Club used to sell R134a , by the jug . I bought my jug of R410a from Johnstone Supply . And a jug of R22 on a different occasion . The R22 was by far the most expensive .

God bless
Wyr


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## Bob Sanders (Nov 10, 2013)

WyrTwister said:


> Much more cost effective to buy it by the jug .


I was carrying it across the border and had concerns about size.


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## WyrTwister (Jul 22, 2013)

Did not want to end up in the pokey ? 

God bless
Wyr


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## Bob Sanders (Nov 10, 2013)

WyrTwister said:


> Did not want to end up in the pokey ?
> 
> God bless
> Wyr


Didn't study up on the r410a (bottled) import laws. Didn't want too lose to much money if it was seized.

Since then however, and interestingly enough in spite of our 'no selling of disposable refrigerant bottles' here, the importation of r410a in a disposable bottle IS permitted. You just can't sell them here.


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