mini split cooling, but not 100%

[CannaBunkerMan]

fuck..ive seen how handy you are and you are saying its a pain? I was about to install one of those self installs as well, i have a hard time setting up a ps3... Ill be following this..

If you had the proper tool set, and someone who's done it before, like evl2me, to help you through it, it's not so bad. There's just a lot of specific convention that you need to learn.

Example? R134a manifolds won't work with R401a systems, since there's a pressure difference between the 2, with the R401a being significantly higher pressure.

Also, clutch-type flaring tools work better than the standard.

I try to never give the impression that something is too difficult to undertake. Research and patience will pay off in the end.

You can do it!

 

[Guest 18340]

So, using the manifold gauge set to determine vacuum level is not sufficient?

No.
Mind you, I've done installs without a micron gauge and those units are still running fine, but the only way to know for sure that you've pulled a vacuum to 500 microns is with a micron gauge.
If you forgo the micron gauge then at least make sure the oil in the vacuum pump is fresh. The fresher the oil the quicker/easier the pump can pull a deep vacuum. And leave the pump running for a few hours if possible.
Btw, the above info you posted about a clutch type flare tool is spot on.

 

[CannaBunkerMan]

Okay, so I just bought the vacuum micron gauge, the correct R-401a vacuum gauge manifold, and the R-401a charger that you linked to above.

Another question, is is possible to pressure test a single indoor unit if you have a dual system, or do you need to do both at the same time?

Also, how long should you pull 500 microns on the system to make sure it's good? Should is stay at or below 500?

 

[Guest 18340]

Okay, so I just bought the vacuum micron gauge, the correct R-401a vacuum gauge manifold, and the R-401a charger that you linked to above.

Another question, is is possible to pressure test a single indoor unit if you have a dual system, or do you need to do both at the same time?

I believe you can pressure test them one at a time since each pair of line set has it's own service port that can be opened/closed individually.
*Mind you, I've never installed a dual head unit. If in doubt about anything I say PLEASE do check around to make sure the procedure is done correctly*

Also, how long should you pull 500 microns on the system to make sure it's good? Should is stay at or below 500?

Within reason, theirs no such thing as pulling a vacuum for too long. I've known tech's who worked on their own equipment and let the vac pump run over night. Mini split manufacturer's generally call for a 10 minute vac, based on a 25' line set. I do an hour minimum just to be uber sure.
"Should it stay at or below 500?" <-A freaking GREAT question! Shows you're paying attention to detail.
Usually it will slowly drift to 1000 microns, and that's acceptable. Ideally you don't want it to go past 1000 or it means you probably have a leak.

Here's a great vid by LG on how to install an LG mini split;
http://www.youtube.com/watch?v=qI5IrR8PceU

The procedure is the same for most all mini's. You'll also see all the extra equipment the pros use.

 

[CannaBunkerMan]

So, I finally got all of the correct adapters and connected my linesets. Then I attached the vacuum pump to the manifold gauge set, then from there to the service port. I left the pump on for a few hours, but it never got below 10,000 microns. Now what? I need to buy more shit, that's what. I need a nitrogen tank to leak test. Spray soapy water to see where the leak is. Mix dish soap and water at a ratio of 1/5 to spray on the fittings.

 

[lobsterbush]

If i were the op i would try to find a trustworthy tech to help out.
I don't have much experience with mini splits but have been doing residential installs for a couple years.

I would recover and vaccuum the system before changing the filter drier and adding a fresh charge. By not vaccuming to begin with moisture was introduced to the system and will be next to impossible to remove said moisture from refrigerant (for a diy'er).

hope you can find someone to give you a hand that has the right tools and some 410A.

 

[takkada]

If i were the op i would try to find a trustworthy tech to help out.
I don't have much experience with mini splits but have been doing residential installs for a couple years.

I would recover and vaccuum the system before changing the filter drier and adding a fresh charge. By not vaccuming to begin with moisture was introduced to the system and will be next to impossible to remove said moisture from refrigerant (for a diy'er).

hope you can find someone to give you a hand that has the right tools and some 410A.

it hard to trust people , i called a tech right out the phone book , i now have good tech , a new friend and a customer . i know its risky but my tech has lots of growers he has helped , he said in his profession this is more common than you think. i know i am lucky to have a good experience . i did the same with an electrician , good luck bro, peace .

 

[CannaBunkerMan]

So, I'm still at this. I've made some progress, but with each success, there's more questions.

I ended up getting a 50# nitrogen tank and regulator to do a leak test, and my issue with not being able to pull more than 10,000 microns became very apparant. My outdoor unit came with 3 connections for 3 indoor units. I have 2 indoor units. The unused port (that I didn't touch), was loose, and was slightly leaking. The soapy water and nitrogen tank made this easy to see. After tightening the unused port caps, I was able to pull 200 microns.

Then I opened up the service ports, and let the coolant into the linesets. I ran into another problem when I tried to add the extra coolant (extra long line sets) to the system. The gague that was linked to earlier in the thread was reading dangerously high pressure when pressed the charge button. I vaguely remembered reading somewhere that you needed to add coolant while the compresser was running. After I turned everything on, the coolant pressure was back into the green. I was a little below the 'low' and 'full' marks on the gauge, so it seems that I need to buy another charging tank to finish the charge.

Now, onto my issue. One of the indoor heads is blowing cool air, but not cold. I'll assume that's because it needs more coolant. My problem is that the other (the larger) indoor air handler is not blowing cool air like the other one. The led indicator light is blinking, with no breaks to indicate an error code, and I can't find a reference online as to what this means.

Also, I noticed that the high side(? larger side) and service port is frosting up. I don't know if this is normal or not. I'm just worried that there's a line kink or something. Why would one unit be working and not the other?

Should I call Mitsubishi tech support to trouble shoot? I've been asking everyone that I know if they know an HVAC tech, but no luck so far. I REALLY wish that I could hire someone that knows what the hell they're doing. This DIY has me pulling out what little hair I have left.

SOS!!! PLEASE HELP!!! SOS!!!

 

[Guest 18340]

Check the communication wire on the unit that's blinking. Check to make sure the wire colors match the indoor and outdoor unit. For example, if you used the red wire for L1 on the outdoor unit then make sure it's wired to L1 on the indoor unit.

 

[CannaBunkerMan]

I'll check in the morning. Do you think that it matters which communication wire terminal I use? I have an A, B, and C, but only 2 of the terminals are being used. There's also an A, B, and C for coolant hookups. The C coolant hookup is larger than the other 2, so I know that the 24,000 indoor air handler goes with that one. Should I match the com wire terminals to the letter on the high and low end coolant hookups? That's what I did, it just feels weird to leave 'B' empty, with 'A' and 'C' wired up.

edit - BTW, is the frost on the service valve and conected copper normal? It looks like it could build up over time, just don't know... I hit the breaker, and decided to try in the morning.

 

[lobsterbush]

Could be frosting up because it's undercharged. You keep saying 401a do you mean 410a. I believe 401a (aka MP39) is a replacement for old R-12. Just curious.

 

[CannaBunkerMan]

So, THAT's why I couldn't search for it on google. Yes, 410a.

 

[Guest 18340]

I'll check in the morning. Do you think that it matters which communication wire terminal I use? I have an A, B, and C, but only 2 of the terminals are being used. There's also an A, B, and C for coolant hookups. The C coolant hookup is larger than the other 2, so I know that the 24,000 indoor air handler goes with that one. Should I match the com wire terminals to the letter on the high and low end coolant hookups? That's what I did, it just feels weird to leave 'B' empty, with 'A' and 'C' wired up.

That whole thing has me confused. I can't quite picture what you're talking about...
I suspected the valve is icing due to low r410 levels.

 

[Guest 18340]

Can u give me the model#?

 

[Smokin Joe]

Evenin fellaz Been keeping up with this 1 since the start. Kinda lurking in the shadows You guys are on the right track. Heres whats going on. The outdoor unit is charged for 1 power head from the factory. For additional heads you must add 410a. You must use care in doing so. 410a is dangerous stuff. It works under very high pressure and will give you almost instant 2nd degree burn if you get in the liquid. That being said "DO NOT" attach your manifold set to the high side( small 3/8 line) while the unit is running unless you know what you are dealing with. Okay you have a manifold set right? Hook the blue hose on the large copper service valve. While unit is running let us know what the pressure is. Not sure about your location but if its around 80f (out doors) you need between 110 and 115 psi (depending on how hot it is in the rooms) to be properly charged. Now not knowing exactly your case but if your line sets were charged with nitrogen and you did not evacuate and pull a strong vacume you are gonna have to dump the freon (recover) pull a strong vacuum and recharge with a close to weighed factory charge and then top off til your pressures are where they need to be. Nitrogen will not damage your unit or contaminate your freon but you will never get it out of the system unless you dump and pump. It will be a thorn in your side at the very least. Hope some of this helps.

 

[CannaBunkerMan]

So, I think I had the high and low sides confused. The 'high' side is the high pressure liquid line? That would put the 'high' side below the 'low' side, to make things more confusing. Here's a picture from before I made the electrical connections, and the model numbers:

MXZ3B30NA / MSZGE09NA + MSZGE24NA (9+24) - Mitsubishi Mr. Slim 17.5 SEER Dual Zone Ductless Mini Split Heat Pump with One 9,000 and One 24,000 BTU Indoor Units

 

[Guest 18340]

Should I match the com wire terminals to the letter on the high and low end coolant hookups? That's what I did, it just feels weird to leave 'B' empty, with 'A' and 'C' wired up.

You did it correctly.

 

[lobsterbush]

Evenin fellaz Been keeping up with this 1 since the start. Kinda lurking in the shadows You guys are on the right track. Heres whats going on. The outdoor unit is charged for 1 power head from the factory. For additional heads you must add 410a. You must use care in doing so. 410a is dangerous stuff. It works under very high pressure and will give you almost instant 2nd degree burn if you get in the liquid. That being said "DO NOT" attach your manifold set to the high side( small 3/8 line) while the unit is running unless you know what you are dealing with. Okay you have a manifold set right? Hook the blue hose on the large copper service valve. While unit is running let us know what the pressure is. Not sure about your location but if its around 80f (out doors) you need between 110 and 115 psi (depending on how hot it is in the rooms) to be properly charged. Now not knowing exactly your case but if your line sets were charged with nitrogen and you did not evacuate and pull a strong vacume you are gonna have to dump the freon (recover) pull a strong vacuum and recharge with a close to weighed factory charge and then top off til your pressures are where they need to be. Nitrogen will not damage your unit or contaminate your freon but you will never get it out of the system unless you dump and pump. It will be a thorn in your side at the very least. Hope some of this helps.

Great advice right here^

 

[CannaBunkerMan]

That IS great advice. Now I don't need to rely on the gauge that came with the coolant tank, since I have my yellow jacket 410a gauge set. I'll check this tomorrow. Thanks

edit - my 2nd coolant refill tank is on the way, it should get here by mid/late week.

 

[Vegan]

wow good read on mini split install woes