Mini Split School

[yeldogt]

I found out about a mini split tech session that was occurring the other day .. and was able to sneak a spot with one of the guys I know. It was held at one of the larger distributer offices.

It was an interesting few hours -- and an eyeopener as to the problems the HVAC industry has. Not being part of the industry I was reluctant to get in too deep .. but, I finally had to ask a couple simple questions.

I wanted to know ...... what's the biggest reason for failure?

Not surprising .. it's installation. And a huge problem is installers using pre-made line sets. You have to use the manufacturer's fitting -- and re-make the flare joint correctly .. evidently, making them corrrectly is a bit of a mystery. Both of these points were not a surprise, as I had read about them previously. Most leaks occur at the joints -- the unit become undercharged .. and the problems start. Often, the leak is not located and the tech overcharges the unit later when servicing.

Another item that was pointed out by one of the guys in the session -- and said as sort of as a joke. He said .. "guys ... please use a level and don't try and eye the unit"

Unfortunately, 1/2 of the session was really a sales pitch for equipment .. but some interesting items did come up.

I used a mini for the first time about 15 years ago. The guy who did it was a real pro -- it was early in the game ... so, he was learning and took his time.

IMO the industry has work towards better installation. Simple things like better instructions .. items to make the installations neater and more palatable for US consumers is needed. Most of the installs I see are horrible -- the big manufacturers should spend some money on batter equipment mounts, lineset covers ... even something as simple as a better way for all the stuff to go through a wall.

I see lots of installs that look as if the installer gave little thought as to how the whole job was going to come together.

 

[James-W]

I agree that if the installer would take more time and do a super good job, that would be ideal and problems would be far less. But the thing is, the more time it takes for the installation the more money the installer would want to charge. That being the case the customer would not be pleased with the cost of installation and would probably want to shop around to find someone to do the installation for a lot less money.

Anyway, I think you have a very good idea there, but getting people to spend the extra money to get the job done right is not going to be an easy thing to do.

 

[yeldogt]

Training gets you skill and skill gets you speed. Have seen more than a few installs where it looked as if the installer never opened the instruction book ... it's rare when I see what I would call a nice install.

Evidently, it's common for HVAC companies to purchase the pre-made line sets vs having bulk long length on hand ... they order a "kit" from a distributer .... just like a DIY guy would do. Well -- if you'r not doing one of the most important things -- making sure the unit is not going to leak by remaking the flare/ using the correct nut .. what's the point?

I'm not a tech -- and I don't have the equipment for pumping everything down. I have only done the equipment setting on my LG many years ago ....but I knew 10+ years ago that the premade linesets had to be fixed prior to use.

I sat in on a couple of hydronic/ radiant tech sessions 25+ years ago .. and it convinced me to sign up for a two day class that a hydronic guru was doing in NY about 5 years later when I was doing my first big full radiant project ... His book is "Pumping Away". It's my bible on every project --

I was really surprised when they were installing my Mitsubishi hyper that the industry has such poor compressor install solutions -- both my Carrier split system and the Mitsubishi Hyper are heat pumps requiring elevation from the pad ... both companies show the need for this .. but offer no solutions. It all third party .. and the available products are weak.

 

[LS6 Tommy]

Evidently, it's common for HVAC companies to purchase the pre-made line sets vs having bulk long length on hand ... they order a "kit" from a distributer .... just like a DIY guy would do. Well -- if you'r not doing one of the most important things -- making sure the unit is not going to leak by remaking the flare/ using the correct nut .. what's the point?

I was really surprised when they were installing my Mitsubishi hyper that the industry has such poor compressor install solutions -- both my Carrier split system and the Mitsubishi Hyper are heat pumps requiring elevation from the pad ... both companies show the need for this .. but offer no solutions. It all third party .. and the available products are weak.

Line set "kits" make more sense for two reasons. First, a contractor has to pay taxes on all the stock in his warehouse. More importantly, line sets come nitrogen purged and sealed to keep moisture out. Once you open a roll of copper up, it's the same as leaving it open to the atmosphere.

"Snow legs" or "snow stands" are very readily available, usually directly from the manufacturer. IDK why you had problems getting them.

Tommy

 

[Dagny]

I will only install them where there is no alternative. I don't like them. the parts are special and very expensive. The compact design makes the fin spacing narrow trapping more dirt.

Running piping on the outside of the building looks like **** no matter how you do it.

 

[yeldogt]

Line set "kits" make more sense for two reasons. First, a contractor has to pay taxes on all the stock in his warehouse. More importantly, line sets come nitrogen purged and sealed to keep moisture out. Once you open a roll of copper up, it's the same as leaving it open to the atmosphere.

"Snow legs" or "snow stands" are very readily available, usually directly from the manufacturer. IDK why you had problems getting them.

Tommy

Maybe you can get the line sets purged and caped .. but all the ones I have seen are simply caped with a plastic dust cap -- they are not sealed. Same with those used in this session. He opened new boxes. And sorry -- how is having insulated coil stock any different vs having the proper product to install a split system? Many mini's need longer line sets vs what available out of a box .. that was another point ... don't splice .. evidently another common problem.

And ... yes ........you can get the feet and the stands. Carrier and Mitsubishi have none available if they make them -- the ones available are mostly junk. So you put a 5-6k compressor on top of $20 worth of cheap plastic that wobbles all over the place.

 

[yeldogt]

I will only install them where there is no alternative. I don't like them. the parts are special and very expensive. The compact design makes the fin spacing narrow trapping more dirt.

Running piping on the outside of the building looks like **** no matter how you do it.

Different manufacturers have had issues with particular components -- I guess to be expected with any product. Maybe it's because of foreign ownership -- but they don't get what is expected in the USA for customer service. Sanyo being one .....basically the leader at one point and Fujitsu with some CS problems.

In some countries they used pre-charged hose -- I'm not sure why these are not used in the USA? If they came in enough sizes it could change the industry -- maybe the USA industry does not want that change. I have cars 15 years old with rubber AC lines and never touched -- I'm sure they could figure this out (longevity). Would allow easier installation with neater tighter covers.

 

[Jackfre]

I will only install them where there is no alternative. I don't like them. the parts are special and very expensive. The compact design makes the fin spacing narrow trapping more dirt.

Running piping on the outside of the building looks like **** no matter how you do it.

Curious how you define "no alternative".

 

[Dagny]

Air handler A coil and conventional condensing unit. Hate to call us lucky but we need heat here 9 months of the year so most homes have a nice heating system.

 

[brewchief]

I've done a handful of minisplits, if I never do another it would be fine with me.

Every single one I've dealt with had instructions that read like they had been translated through at least 4 or 5 different languages.

None of them have enough room to make up the line set connections, it's always a fight to get them hooked up and hanging on the wall, drain is just as bad, you get a short piece of crappy tube that is an odd size that you are supposed to do something with.

Line sets are available in a 20 foot or 50 foot length from most of my wholesalers, I've never in my life heard of line sets being sold in bulk lengths, dealing with a 50 foot line set is bad enough, I can't imagine trying to wrestle a longer one.

The plastic caps on the line sets work just fine, in fact one of my local wholesalers probably has 10,000 feet of refrigeration copper in 20 foot lengths with plastic caps on it.


Mini splits get installed like **** because everyone expects to get one installed for a couple hundred bucks over the price that they can find it for online so they hire the cheapest guy to do it.

 

[yeldogt]

I've done a handful of minisplits, if I never do another it would be fine with me.

Every single one I've dealt with had instructions that read like they had been translated through at least 4 or 5 different languages.

None of them have enough room to make up the line set connections, it's always a fight to get them hooked up and hanging on the wall, drain is just as bad, you get a short piece of crappy tube that is an odd size that you are supposed to do something with.

Line sets are available in a 20 foot or 50 foot length from most of my wholesalers, I've never in my life heard of line sets being sold in bulk lengths, dealing with a 50 foot line set is bad enough, I can't imagine trying to wrestle a longer one.

The plastic caps on the line sets work just fine, in fact one of my local wholesalers probably has 10,000 feet of refrigeration copper in 20 foot lengths with plastic caps on it.


Mini splits get installed like **** because everyone expects to get one installed for a couple hundred bucks over the price that they can find it for online so they hire the cheapest guy to do it.

Agree with most -- some simple design changes are needed. Mitsubishi does not want splicing on the line sets -- so they need the long "bulk" product when doing them. At my house two cassettes were used in the upper two bedrooms of a cape. The line came with a heavy protective cover over the insulation/ tubing -- it was installed in the attic and covered with insulation. Tubing was in a very big box!

The dust caps do work -- I have not seen where the caps were sealing a nitrogen filled line set .. just a dust cap.

 

[Brian_WK]

We quit using the manufacturer's line sets a few years ago due to the wonkey flare nut size thin copper and crappy insulation. Ran all soft copper roll and new armorflex insulation and **** glued the ends.
Any time the lineset needs to be brazed you have to purge nitrogen otherwise the scale will plug the electronic expansion valves. This should be done on any A/C system that needs to be brazed.
Precharged lines look like and are ****. Nothing worse then having 3 foot extra of lineset sticking out by the condenser or Evaporator.
We always had our wall mount and snow stands made from aluminum square tubing by a local welder he had a jig set up and could hammer one out in 2 hours. never rusted and always a perfect fit.
We only installed Sanyo then Fujitsu when they bought them out.
The only training these guys provide is factory training the "classes" at distributors are worth NATE hours but are a sales pitch and useless otherwise.

I like mini splits for A/C just not a great fit for my area if you need heating they struggle just like any other air heat pump in my climate especially if you have natural gas available which is dirt cheap around here.

Brian

 

[Voi]

I like mini splits for A/C just not a great fit for my area if you need heating they struggle just like any other air heat pump in my climate especially if you have natural gas available which is dirt cheap around here.

Brian do you know anyone on my side of the state that you'd recommend for a mini split install? We have a cabin down near Hill City and I'd like to use a mini split.

Black Hills Power has their own installers now and I liked the guys I talked to but my main concern is service after the sale/install.

By the way, I'm not concerned about the ability of the heat pump to keep up. We'll have supplemental heat of some sort anyways.

 

[justinjoyal]

I've done a handful of minisplits, if I never do another it would be fine with me.



Every single one I've dealt with had instructions that read like they had been translated through at least 4 or 5 different languages.



None of them have enough room to make up the line set connections, it's always a fight to get them hooked up and hanging on the wall, drain is just as bad, you get a short piece of crappy tube that is an odd size that you are supposed to do something with.



Line sets are available in a 20 foot or 50 foot length from most of my wholesalers, I've never in my life heard of line sets being sold in bulk lengths, dealing with a 50 foot line set is bad enough, I can't imagine trying to wrestle a longer one.

You simply are not used to them or don't have the proper techniques... no offense.

We buy soft copper piping in 50 or 100 ft rolls and use armorflex for insulation. Works great and is easy to work with.

Installing mini–splits is a breeze when you know what you are doing.

Also regarding the stands, our suppliers sell aluminum wall brackets or floor stands that work great, are cheap and will not rust.

 

[eddieK]

Line sets - Most are not just dust sealed, they come plugged and charged with nitrogen. Once cut always seal off or tape off scrap immediately.

No matter if you use the pre made flares or make your own, you simply do a nitrogen test to 400 PSI FIRST - locate leaks and seal them and ALWAYS use refrigerant oil on flares as the FINAL seal (leaks can only be in so many easy to access locations if you put it together correctly)...only after you are certain there are no leaks do you open the valves.

Evacuation is also critical for long term problem free operation.

The instructions are trash...they are poorly translated and cause more confusion than anything.

 

[tyme2par4]

Line sets - Most are not just dust sealed, they come plugged and charged with nitrogen. Once cut always seal off or tape off scrap immediately.

I've bought both Mitsubishi line sets and JMF line sets, and neither were sealed and charged with Nitrogen, Both have premade flares, and a small plastic cap loosely screwed into the flare nut.

 

[86turbodsl]

I sat in on a couple of hydronic/ radiant tech sessions 25+ years ago .. and it convinced me to sign up for a two day class that a hydronic guru was doing in NY about 5 years later when I was doing my first big full radiant project ... His book is "Pumping Away". It's my bible on every project --

Yes, Seigenthaler is great. I have a couple of his books too. I even talked to him once, he and i were discussing my hydronic install at my new house, he didn't like that i was a DIY installer not a contractor (even though i am an M.E. and know my stuff) and clammed up. I don't fault him, but it does illustrate how closed that industry is.

 

[zmaxmotorsports]

The install is the secret to most things,no matter what the trade.

 

[eddieK]

I've bought both Mitsubishi line sets and JMF line sets, and neither were sealed and charged with Nitrogen, Both have premade flares, and a small plastic cap loosely screwed into the flare nut.

My suppliers carry them and I choose them.

 

[LS6 Tommy]

Maybe you can get the line sets purged and caped .. but all the ones I have seen are simply caped with a plastic dust cap -- they are not sealed. Same with those used in this session. He opened new boxes. And sorry -- how is having insulated coil stock any different vs having the proper product to install a split system? Many mini's need longer line sets vs what available out of a box .. that was another point ... don't splice .. evidently another common problem.

I should have been clearer. The cap IS the seal. Once you cut a length off, there's no way to repurge the leftover copper. If you need to make a longer run it's preferred to start from a new coil. Is it always done that way? No. It isn't technically "wrong", either, but some techs are pickier than others about procedures. I was just trying to answer your question. I wasn't arguing with you.



Tommy

 

[eddieK]

I should have been clearer. The cap IS the seal. Once you cut a length off, there's no way to repurge the leftover copper. If you need to make a longer run it's preferred to start from a new coil. Is it always done that way? No. It isn't technically "wrong", either, but some techs are pickier than others about procedures. I was just trying to answer your question. I wasn't arguing with you.



Tommy

This is why you sweep nitrogen and then test the closed system to 400 PSI and then evacuate to 500 microns, close inline valves and wait 7 to 10 minutes, should not rise above 1000 microns..if your gage rises to above 2000 microns you still have moisture (evacuate again). If it continues to rise you have a leak in system.

 

[LS6 Tommy]

This is why you sweep nitrogen and then test the closed system to 400 PSI and then evacuate to 500 microns, close inline valves and wait 7 to 10 minutes, should not rise above 1000 microns..if your gage rises to above 2000 microns you still have moisture (evacuate again). If it continues to rise you have a leak in system.

You're preaching to the choir, eddie... Like I said, it isn't "wrong" to use open copper, I just prefer not to if possible. I've even seen guys solder in an access port, purge nitrogen through the tubing as they pinch off and solder the other end... That's overkill for most people...

Tommy

 

[yeldogt]

The box this line-set came out of was new -- but it was not sealed under any pressure. The internal insulation was covered with a white plastic covering.