Ductless Failure (Mitsubishi mini-split) - Page 3

WyrTwister · 01-12-17, 09:34 PM

Do the newer , higher SEER MS's use less refrigerant ( for the same BTU ) , compared to the older / lower SEER units ( like our 13 SEER living room unit ) ?

God bless
Wyr

Shelby · 01-13-17, 01:11 PM

Again, amazing information here....

Xringer (Rich), I copied your post and forwarded it to my son, he replied that he has the following equipment but doesn't have any of the recovery materials.

"Fieldpiece scale & vacuum gauge
Yellow Jacket 2 stage pump, flaring tool, spare cores & mantooth V2(?!?)
Hilmor ball valve lines & vacuum line
25lb R410a
2 small tanks of nitrogen
Mini-split torque wrench kit
Leak detector spray
Nylog (he indicates it's a bottle from 2 years ago)"

Looking at my receipts from the install back in 2013, I see a 15' Mitsubishi line set. If I recall, they cut the lines shorter but couldn't go any shorter than... Sorry, can't remember but I can have my son check if it helps..

I took a photo of the side of the unit this morning. It indicates 'Factory Charged' with 1lb 12oz of R410A.

--Shelby

Quote:

Originally Posted by Xringer

When pulling the vacuum, you'll need an adapter to match the service port to the standard 1/4" hose fitting..
The best kind of adapters have a cut-off valve.. (see red valve handle) Highly recommended.
https://www.amazon.com/Adapter-R410a...dp/B00M0VL5B0/

When you connect the fill-hose(with cut-off) to that adapter, there will be some air trapped inside.
So, leave it a little loose, and bleed a tiny bit of R410a into the connection as you tighten it up. Flushing out the air..

I hope your son has a good scale to 'weigh in' the R410a.
The tank has to be upside down on the scale, so that liquid flows, not gas..
(You could rock the tank around a little before starting, to mix it up a bit).

The R410a should be sucked right into an evacuated system.. (Should be under 200 microns at least).
You have to watch the scale and allow a very slow in-flow, so there's no over-filling..
If the vacuum doesn't allow enough weight to be pulled in,
then start running the unit in cooling mode.
That will enable the compressor to pull in the R410a.
It will flow into the 4way valve, into the accumulator, and onto the compressor..
You have to go slow, so that liquid is not injected into the compressor.
It's made to pump gas..
Once the right weight is indicated on the scale, shut off the fill hose cut-off.

Then shut the tank valve. Re-open the fill-hose cut-off (10 seconds) to allow the compressor to lower the pressure inside the fill hose.
Close all cut-offs and use gloves to very quickly remove the Adapter
from the service port.. Some R-410a will vent for a second.. If you fail to be quick, a lot of it will vent.. Not good. Global warming..

If you have an extra long line-set, (over 25 feet) you will have to add extra weight R410a.. The ounces per-foot (above 25) amount is shown in the install manual.
If you line set is under 15 feet, you might want to under-fill the system a bit. Per the install manual..
Hope your son also has a micron gauge too! Really necessary to get a good vacuum..

That's all I can think of now.. Maybe the other guys have a better way of doing this..

Shelby · 01-13-17, 01:12 PM

Hi Wyr,

I have two 9,000 BTU Hyper Heat units. The one that's having a problem is 21 or 22 SEER and the other is 28 SEER. The problem unit holds 1lb 12oz.

Hope that helps,
Shelby

Quote:

Originally Posted by WyrTwister

Do the newer , higher SEER MS's use less refrigerant ( for the same BTU ) , compared to the older / lower SEER units ( like our 13 SEER living room unit ) ?

God bless
Wyr

Xringer · 01-13-17, 03:04 PM

Shelby it sounds like your Son has the right tools for the job..
I'm pretty sure no recovery is going to be needed on this project.

If your line set is approximately 15 feet, 28 oz of R410a should work great..

Good Luck

WyrTwister · 01-13-17, 03:37 PM

You are way past me . The 2nd MS we installed in our bedroom is just a 16 SEER . 11,600 or 11,800 BTU .

I 100% agree with Xinger . If the system has leaked to zero psi , I can see no need for recovery equipment .

Just guessing , but I think the less refrigerant the MS holds , the more critical it is to weigh the charge of refrigerant ?

I think I first purchased Nylog Blue for automotive R134a then used it for R410a . The make Nylog Red for refrigerants that use mineral oil .

I suspect , as long as I keep the little squeeze bottle capped properly , it will last a long time in storage .

So , you are going to take the IDU off the wall , disconnect the line set and take the IDU down to work on it ? And replace the evaporator coil in the original system ? Then put everything back together ?

Not sure how your line set is run / installed . Reversing the process on either of my MS's , to disconnect the line set from the IDU would be a chore .

If your MS had 100% leaked out & moisture / air entered the system , seems to me you need to purge the system really well with dry nitrogen to try to flush out as much moisture as you can . Then do a really good job of vacuuming the system .

I think I would look into replacing / adding a new filter dryer while flowing dry nitrogen through the dryer . Then quickly get the system buttoned up .

Wish you all the luck in the world & please keep us updated .

God bless
Wyr

Shelby · 02-04-17, 04:16 PM

Many apologies for the delay in updating this thread. I received the new part on Thursday (a revised part from Mitsubishi) and my son arrived bright and early this morning - eager to get started.

He removed and disassembled the indoor unit - talk about filthy. Are you ladies/gentlemen cleaning the blower wheels annually? If not you might want to consider it.

It definitely took longer for him to disassemble because of all the photos he took so I could document the procedure. He cleaned all the parts and took the blower wheel outside to pressure spray out the gunk. He installed the new heat ex. and took about the same time to assemble due to all the photos. The unit is back on the wall and looks like new.

Outside, he inspected the flares and discovered they were damaged (not the word he used) on the side connecting to the indoor unit. He suspected the A/C repair people over tightened them as they were slightly warped. He removed all four of the flares and re-flared them. A little nylog and he torqued them to spec. He was then able to vacuum the system down to 67 microns in about 5 minutes. He isolated the pump from the gauge and let it sit for an hour. It drifted to about 90 and held.

And we're now in the stage where he pressured the system with dry nitrogen. We monitored it for an hour and it's held pretty steady. The temps are dropping outside so he's going to come back in the morning to check if the pressure is still holding. He'll then open the valves and pull another deep vacuum and weigh in the charge...

Fingers crossed... And some photos.. In one of the photos you can see the refrigerant leak (oil) on the left front side of the heat ex.

WyrTwister · 02-04-17, 06:34 PM

Were the connections to the heat exchanger brazed / silver soldered ?

God bless
Wyr

stevehull · 02-05-17, 07:38 AM

Son is doing a GREAT job. Let us know how it works!

Steve

Shelby · 02-05-17, 02:40 PM

Hi WyrTwister,

The connections leading to the indoor unit (on the outside of the house) were flared.

--Shelby

Quote:

Originally Posted by WyrTwister

Were the connections to the heat exchanger brazed / silver soldered ?

God bless
Wyr

Shelby · 02-05-17, 02:42 PM

Thank you so much Steve, you made his day...

--Shelby

Quote:

Originally Posted by stevehull

Son is doing a GREAT job. Let us know how it works!

Steve

01-13-17, 03:04 PM	#24
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Shelby it sounds like your Son has the right tools for the job.. I'm pretty sure no recovery is going to be needed on this project. If your line set is approximately 15 feet, 28 oz of R410a should work great.. Good Luck __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

02-04-17, 04:16 PM	#26
Shelby Lurking Renovator Join Date: Dec 2016 Location: Texas Posts: 14 Thanks: 3 Thanked 3 Times in 2 Posts	Many apologies for the delay in updating this thread. I received the new part on Thursday (a revised part from Mitsubishi) and my son arrived bright and early this morning - eager to get started. He removed and disassembled the indoor unit - talk about filthy. Are you ladies/gentlemen cleaning the blower wheels annually? If not you might want to consider it. It definitely took longer for him to disassemble because of all the photos he took so I could document the procedure. He cleaned all the parts and took the blower wheel outside to pressure spray out the gunk. He installed the new heat ex. and took about the same time to assemble due to all the photos. The unit is back on the wall and looks like new. Outside, he inspected the flares and discovered they were damaged (not the word he used) on the side connecting to the indoor unit. He suspected the A/C repair people over tightened them as they were slightly warped. He removed all four of the flares and re-flared them. A little nylog and he torqued them to spec. He was then able to vacuum the system down to 67 microns in about 5 minutes. He isolated the pump from the gauge and let it sit for an hour. It drifted to about 90 and held. And we're now in the stage where he pressured the system with dry nitrogen. We monitored it for an hour and it's held pretty steady. The temps are dropping outside so he's going to come back in the morning to check if the pressure is still holding. He'll then open the valves and pull another deep vacuum and weigh in the charge... Fingers crossed... And some photos.. In one of the photos you can see the refrigerant leak (oil) on the left front side of the heat ex. Attached Thumbnails

02-05-17, 07:38 AM	#28
stevehull Steve Hull Join Date: Dec 2012 Location: hilly, tree covered Arcadia, OK USA Posts: 826 Thanks: 241 Thanked 165 Times in 123 Posts	Son is doing a GREAT job. Let us know how it works! Steve __________________ consulting on geothermal heating/cooling & rational energy use since 1990

01-12-17, 09:34 PM	#21
WyrTwister Master EcoRenovator Join Date: Jun 2013 Location: USA Posts: 543 Thanks: 6 Thanked 44 Times in 38 Posts	Do the newer , higher SEER MS's use less refrigerant ( for the same BTU ) , compared to the older / lower SEER units ( like our 13 SEER living room unit ) ? God bless Wyr

01-13-17, 03:37 PM	#25
WyrTwister Master EcoRenovator Join Date: Jun 2013 Location: USA Posts: 543 Thanks: 6 Thanked 44 Times in 38 Posts	You are way past me . The 2nd MS we installed in our bedroom is just a 16 SEER . 11,600 or 11,800 BTU . I 100% agree with Xinger . If the system has leaked to zero psi , I can see no need for recovery equipment . Just guessing , but I think the less refrigerant the MS holds , the more critical it is to weigh the charge of refrigerant ? I think I first purchased Nylog Blue for automotive R134a then used it for R410a . The make Nylog Red for refrigerants that use mineral oil . I suspect , as long as I keep the little squeeze bottle capped properly , it will last a long time in storage . So , you are going to take the IDU off the wall , disconnect the line set and take the IDU down to work on it ? And replace the evaporator coil in the original system ? Then put everything back together ? Not sure how your line set is run / installed . Reversing the process on either of my MS's , to disconnect the line set from the IDU would be a chore . If your MS had 100% leaked out & moisture / air entered the system , seems to me you need to purge the system really well with dry nitrogen to try to flush out as much moisture as you can . Then do a really good job of vacuuming the system . I think I would look into replacing / adding a new filter dryer while flowing dry nitrogen through the dryer . Then quickly get the system buttoned up . Wish you all the luck in the world & please keep us updated . God bless Wyr

02-04-17, 06:34 PM	#27
WyrTwister Master EcoRenovator Join Date: Jun 2013 Location: USA Posts: 543 Thanks: 6 Thanked 44 Times in 38 Posts	Were the connections to the heat exchanger brazed / silver soldered ? God bless Wyr