LG LMU245HV mini split 3 zone heat pump DIY - Page 6

Xringer · 06-21-13, 09:44 AM

Quote:

Originally Posted by Jumpmaster

Xringer,
I have got the three inside units mounted on the brackets and I am ready to bend the copper tubes away from the unit. The instructions say to bend the tubes down and away from the unit. Then it gives instructions on bending the tubing left if you are running the lines to the left. My lines will run straight back into a wall. I am thinking it would be better to bend the tubes straight back from the unit in one movement. How did you bend your tubing on your installation? Thanks.
Scott

At the point of exit, (from the indoor unit) the lines seem to be more flexible
than regular lineset copper. My first install was straight back into the wall too.
(Second install needed a downward bend).
IIRC, I did both jobs slowly, trying to hold firmly onto the lineset,
squeezing the insulation down flat as possible,
while pressing with my thumbs and fingers while pulling the lineset out from it's 'factory' position.
The idea was to distribute the bending pressure over an 'area' of the tube,
and not apply a 'point' pressure that would kink it.

Once the line came outside the wall (outdoors), I used a 2.5" OD wooden dowel,
pushed into the bottom of the line set, as I bent it downwards.

Before:

After: You can see the dowel sitting in the upper right of this pic.

Bending around the wood gave me a nice smooth turn.

Outdoors, where I wanted to make turns with the main lineset,
I would use a large paint bucket etc as a form to bend around.
If you mess up, be ready to spend another $95 on copper.

Elcam84 · 06-23-13, 10:49 AM

Been lurking here for a while. Seems to be a good group of people that like to engineer and build stuff instead of the common ones that think you can't do that... (something that is missing anymore) Anyway

I have installed quite a few mini spits and other units. I used to do commercial refrigeration. The LG units are good. They have a little better quality to some of their smaller parts than some others.

The issues I have with any of them is usually related to drainlines being goofy size or material and difficult to plumb into other pipe. Very thin rubitex on the line sets. (the white will hold up to UV regular black type will not)

I have installed a few Pridiom units and to be honest most all minisplits are made the same with the exception of the mitsubishi. The Pridiom ones are the best bang for the buck that I have found. I have a condenser for one that I plan to use in the shop as a second AC once I get an inside unit for it.

Mitsubishi now has a goofy install and I will not install a multizone one for anyone. They are overcomplicated. They use Y pipes instead of direct runs. The Y pipes have to be installed within 10* of flat or vertical and then there are electrical sub boxes that the units talk to before they talk to the condenser. Difficult install and makes it nearly impossible to install in many houses without tearing out drywall etc go get things where they need to be.

A couple tips. The main failure on the inverter systems is the power supply. The capacitors for the 380v DC are big and since they are outside in the heat in a box that makes even more heat the caps tend to blow over time. Usually you can just replace the caps with new ones and all is well again and you can get higher heat rated caps that are better than OE.
During install I have had some units not communicate. This is 99.9% due to the inside unit being assembled incorrectly at the factory. There are 3 wires two 110 and one com wire. Well what they don't tell you and the tech reps don't know is that part of the communication is also on one of the 110 leads. What happens is they hook them up backwards at the factory at times and it will never work.
So if you install a system and it comes up with a communication error swap the two 110 feed wires to the outside unit and it will most likely work. That's how I ended up with an extra Pridiom condenser cause the tech reps didn't know their product. I figured it out when I pulled out my oscilloscope.

For tools the Harborfreight vacuum pump works great. Go with the small one. You don't need the high CFM. In fact most techs I know still working use their pumps cause they are often stolen or dropped so why have a $$$ one.
The Micron meter is nice but I have never once seen a tech use one or even have one.

AC_Hacker · 06-23-13, 12:13 PM

Quote:

Originally Posted by Elcam84

Been lurking here for a while. Seems to be a good group of people that like to engineer and build stuff instead of the common ones that think you can't do that...

Thanks for the information, all very useful.

However....

Quote:

Originally Posted by Elcam84

...The Micron meter is nice but I have never once seen a tech use one or even have one.

So how do you know for sure that your vacuum pump actually is pulling the required vacuum? This is especially important to know if you have a used or borrowed vacuum pump. Also, how do you know for sure that all of your seals and hoses are really up to snuff? I am strictly an amateur, and since I have gotten a micron gauge, I use it all the time and the problems that I have had with bad hoses, seals and fittings would never have been apparent to me without the micron gauge... I would never have known that I was doing unacceptable work. Also problems with insufficient vacuum and insufficient water removal may not appear for a year or two... and then as shortened system life. This may not be important to a field tech, since it would mean more paying jobs. To an owner-installer, or refrigeration experimenter (hacker) there is nothing to be gained by doing anything less than perfect work.

I think you underestimate the importance of a micron gauge.

Best,

-AC

Elcam84 · 06-23-13, 01:31 PM

I have nothing against using one. It just isn't common practice in the industry. Everyone trusts their gauges to read reasonably accurately which most now are digital and those have even done away with the need for a seperate meter if you are going for perfection. Most everyone goes by the gauge and if the pump pulls down to 30 and holds there for long enough then it's good. Course there are guys I have seen from some companies not even pull a vacuum on a system and instead just flush refrigerant through it and they call it good...
You are doing it the way everyone should be doing it. I have been known to leave a vacuum pump running on a system for 2hours sometimes more. Longer runs don't hurt anything. Course the grocery stores we did we had to rent a diesel powered vacuum pump from a bulk refrigerant supplier then have them come charge it up.

Xringer · 06-23-13, 03:26 PM

I kinda like owning a Micron gauge because it looks so cool..

Just kidding.. If I was an installer with years of experience,
and knew the hardware I was installing was unlikely to fail,
(because everything I had installed before, was still working fine),
I might skip spending money on an expensive piece of test gear.

I have twice sold overly expensive oscilloscopes, (got them for cheap money),
because 99% of my test requirements can be handled by a basic 100 MHz scope..
Plus, it's a lot smaller and lighter..

~~~

I was wondering about those larger inverter caps. How to they fare in cold weather?

AC_Hacker · 06-23-13, 04:17 PM

Quote:

Originally Posted by Elcam84

...Everyone trusts their gauges to read reasonably accurately which most now are digital and those have even done away with the need for a seperate meter if you are going for perfection. Most everyone goes by the gauge and if the pump pulls down to 30 and holds there for long enough then it's good...

Elcam84, I hope you don't take this personally, but there are many people who come to this site and want to try their hand at doing their own install, or hack some system to behave in a novel way, which we completely support. It is quite likely that this will be their very first experience with vapor-compression machinery. We want them to be successful.

By looking at a standard vacuum gauge, which goes down to 30 (whether analog or digital), they could easily think that when they hit 30, they have achieved a total vacuum, and have removed all air and water from the system, and can safely proceed... not knowing that their gauge is unable to respond to very small, but critical changes at the extreme end.

We have already had lengthy discussions about the important vacuum events that happen at the very low end of the dial... when water actually gets evaporated.

It is for this reason that we are encouraging our readers to beg, borrow or buy a micron gauge when they set up equipment.

Your comment that:

> [using a micron gauge] ...just isn't common practice in the industry.

...does not square with recommendations from professionals I have seen seen on HVAC blogs.

I have no doubt that neither you, nor anyone you work with, uses a micron gauge.

But remember, when you finish with a job, you get to walk away, when our readers finish with a job, they will be living with it for years to come. We want them to know and use the best practices available.

-AC

Elcam84 · 06-23-13, 05:11 PM

I'm not trying to steer the readers away from wanting to use the gauge. Just stating that it isn't the way it's done in the field. Many do recommend it but few actually use it themselves.

The gauge is a great time saver because instead of running the pump X amount of time after it hits 30" you can look at the gauge and know you are there. Say the system gets there in say 1hour but without the gauge you follow SOP and you end up running the pump 2hours instead just to make sure you got there because you didn't have the tool to verify so you overshoot. My point is both get you to the same place just one takes longer to make sure.

Yes there are allot of really cool ideas on here which is why I like the board. Not afraid to try something different. I am impressed with the attention to detail I see here. Like the gauge there are other areas that you guys go above and beyond SOP in the field. Course allot more fun and easier than the stuff we did fixing coolers in kitchens, grocery stores etc.. Try building a grocery store with used equipment the owner provides...

06-23-13, 03:26 PM	#55
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	I kinda like owning a Micron gauge because it looks so cool.. Just kidding.. If I was an installer with years of experience, and knew the hardware I was installing was unlikely to fail, (because everything I had installed before, was still working fine), I might skip spending money on an expensive piece of test gear. I have twice sold overly expensive oscilloscopes, (got them for cheap money), because 99% of my test requirements can be handled by a basic 100 MHz scope.. Plus, it's a lot smaller and lighter.. ~~~ I was wondering about those larger inverter caps. How to they fare in cold weather? __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

06-23-13, 10:49 AM	#52
Elcam84 Apprentice EcoRenovator Join Date: Jun 2013 Location: TX Posts: 275 Thanks: 2 Thanked 31 Times in 24 Posts	Been lurking here for a while. Seems to be a good group of people that like to engineer and build stuff instead of the common ones that think you can't do that... (something that is missing anymore) Anyway I have installed quite a few mini spits and other units. I used to do commercial refrigeration. The LG units are good. They have a little better quality to some of their smaller parts than some others. The issues I have with any of them is usually related to drainlines being goofy size or material and difficult to plumb into other pipe. Very thin rubitex on the line sets. (the white will hold up to UV regular black type will not) I have installed a few Pridiom units and to be honest most all minisplits are made the same with the exception of the mitsubishi. The Pridiom ones are the best bang for the buck that I have found. I have a condenser for one that I plan to use in the shop as a second AC once I get an inside unit for it. Mitsubishi now has a goofy install and I will not install a multizone one for anyone. They are overcomplicated. They use Y pipes instead of direct runs. The Y pipes have to be installed within 10* of flat or vertical and then there are electrical sub boxes that the units talk to before they talk to the condenser. Difficult install and makes it nearly impossible to install in many houses without tearing out drywall etc go get things where they need to be. A couple tips. The main failure on the inverter systems is the power supply. The capacitors for the 380v DC are big and since they are outside in the heat in a box that makes even more heat the caps tend to blow over time. Usually you can just replace the caps with new ones and all is well again and you can get higher heat rated caps that are better than OE. During install I have had some units not communicate. This is 99.9% due to the inside unit being assembled incorrectly at the factory. There are 3 wires two 110 and one com wire. Well what they don't tell you and the tech reps don't know is that part of the communication is also on one of the 110 leads. What happens is they hook them up backwards at the factory at times and it will never work. So if you install a system and it comes up with a communication error swap the two 110 feed wires to the outside unit and it will most likely work. That's how I ended up with an extra Pridiom condenser cause the tech reps didn't know their product. I figured it out when I pulled out my oscilloscope. For tools the Harborfreight vacuum pump works great. Go with the small one. You don't need the high CFM. In fact most techs I know still working use their pumps cause they are often stolen or dropped so why have a $$$ one. The Micron meter is nice but I have never once seen a tech use one or even have one.

06-23-13, 01:31 PM	#54
Elcam84 Apprentice EcoRenovator Join Date: Jun 2013 Location: TX Posts: 275 Thanks: 2 Thanked 31 Times in 24 Posts	I have nothing against using one. It just isn't common practice in the industry. Everyone trusts their gauges to read reasonably accurately which most now are digital and those have even done away with the need for a seperate meter if you are going for perfection. Most everyone goes by the gauge and if the pump pulls down to 30 and holds there for long enough then it's good. Course there are guys I have seen from some companies not even pull a vacuum on a system and instead just flush refrigerant through it and they call it good... You are doing it the way everyone should be doing it. I have been known to leave a vacuum pump running on a system for 2hours sometimes more. Longer runs don't hurt anything. Course the grocery stores we did we had to rent a diesel powered vacuum pump from a bulk refrigerant supplier then have them come charge it up.

06-23-13, 05:11 PM	#57
Elcam84 Apprentice EcoRenovator Join Date: Jun 2013 Location: TX Posts: 275 Thanks: 2 Thanked 31 Times in 24 Posts	I'm not trying to steer the readers away from wanting to use the gauge. Just stating that it isn't the way it's done in the field. Many do recommend it but few actually use it themselves. The gauge is a great time saver because instead of running the pump X amount of time after it hits 30" you can look at the gauge and know you are there. Say the system gets there in say 1hour but without the gauge you follow SOP and you end up running the pump 2hours instead just to make sure you got there because you didn't have the tool to verify so you overshoot. My point is both get you to the same place just one takes longer to make sure. Yes there are allot of really cool ideas on here which is why I like the board. Not afraid to try something different. I am impressed with the attention to detail I see here. Like the gauge there are other areas that you guys go above and beyond SOP in the field. Course allot more fun and easier than the stuff we did fixing coolers in kitchens, grocery stores etc.. Try building a grocery store with used equipment the owner provides...