Mini Split Install Done!

[Jack Frederick]

A couple suggestions on mini-split heat pumps (mshp). I represented one of the major brands for 14 years in my business and wouldn't be without them in my home. If you are considering a mshp make sure you understand the performance limits on each model you are considering. Even within one manuf line there are different models of the same size that have different specs. Some will heat down to 5*, others will operate down to -20*. Be right on this or you are stepping into your own personal twilight zone, especially if you buy on-line. Don't oversize them. I have found that they consistently exceed expectations. On modulating equipment th low range is more important than the high. On the wall brackets, definitely anchor them to the studs, but I ALWAYS put a toggle at each corner. I have found the brackets to be so light that in order for the evap to mount nicely to the wall the toggles are necessary. So not mount them to high on the wall. 8' is about max. CLEAN THEM. A contractor will tell you to clean the filters and yes that is necessary. However those filters are not great and with wood shop dust (even with primary and secondary dust control) and the fin spacing on the coils and the fact that about 40% of the coils surface slopes down toward the back, you need to monitor the condition of the coil and prepare to clean them. It is not just the coil. The small curved blade fans load up and there goes your air flow. Also in a humid climate I would want to know how to completely remove the cover, take a can of compressed air and a shop vac and blow off/vacuum the electronic area. The current issue of FWW has an article referencing Chris Beckvoort's mshp install saying it has been trouble free. I wrote the editor suggesting it was time for a thorough cleaning. Btw, how does he keep his shop so clean?

[Jack Frederick]

Jim, you can rout the refrigerant piping up down or sideways as you choose. The drain is the problem. Mshp's are excellent at dehumidification and in Buck's Cty, you will need plenty of it. A gravity drain is desirable as a result, so you will likely have to drill the wall for that. Check the manuf spec on your evaporator to confirm the piping layout. I use Fujitsu's as I know them best. I drill the hole on the left side and move the drain to the left side. That allows the drain line to exit the building directly and makes it future accessible at the connection and easy to deal with. Also the line set goes through that hole and lays across the back of the unit, again allowing easy future access. It is a machine. Build it so you can service it. Another big advantage of putting the drain on the left is that it makes it easier to close the unit down onto the mounting bracket. With the drain line laying across the back it is a classic example of 5# in a 4# bag. You end up shoving things around trying to get the unit to close down and frequently end up trapping the drain line. DO NOT be that guy. Therein lies madness Flooding condensate tray, standing water, mold mildew. Running the line set out of the wall directly on the rt kinds two blocks you for future access. If you choose to pump your condensate, Aspen makes some nice mini pumps, but I find them to be annoying. On the drain connection I have found the best way to deal with them is to Use a plastic barbed fitting with hose clamp X 1/2 or 3/4" mpt plastic fitting into the pvc female adapter.

[Jim Becker]

Jack, your comments are appreciated. After looking at things more closely I should be fine with "normal" through the wall routing of everything because the upper extent of the existing window area will fall within the correct plane for connections out the back of the inside unit, either left or right side, depending on how I decide to handle one other small thing. The existing electrical run is sized correctly for cable, so that's just a matter of re-termination/extension and conversion to 240v. Outside, the drain line will not be an issue at all. The only remaining challenge is to decide whether or not to "ground mount" the external unit or wall mount it on the outside of the new wall that fills in the window opening. The building at that point is partially below grade and putting it "in" a window well is not a permitted configuration. I can do off to the side, above or below the window area on a leveled area on the slope or wall mount directly below "on" the new window wall but above ground.

[Thomas Crawford]

Jack -

Does it matter where you hang the mini-split? Say in a rectangular space should it be a on a long or short wall, centered etc?

[Jack Frederick]

I never ground mount the units. Airtec make nice wall brackets. Your unit stays cleaner longer. You will have fewer bugs. You don't have to kneel to work on it. Also, in a northern climate you want to be above the snow. When it is cold your unit will go into defrost mode periodically. The condensate that forms in the condensing unit has to drain somewhere and has to have a clear path to do so. I have seen ground mounted units build up an ice block to the point it froze those nice high efficiency fan blades in place. Don't be that guy. I have seen ground mounted units that the face of the coil was mudded solid from the splash from rain and flooding gutters. Raise it up.

[Hoang N Nguyen]

I just got a 3 zone Mitsubishi 24k BTUH 20 SHEER system installed in my basement shop last week and I'm LOVING not walking into a 55 degree shop during the winter. I hired a Mitsubishi diamond contractor to install mine, My knowledge of HVAC is zero to none so I didn't want to mess with it. Although, now that I've seen how they did it, I wish I would have done it myself because it looked so easy. The one perk of having a Mitsubishi diamond contractor do my install is that Mitsubishi extends my warranty from 10 years to 12 years. The contractor ran all my copper lines up the walls and along the ceiling joist and all 3 lines exit the house at one location where the outdoor unit is. 2 of my condensate drain lines were ran along my walls, drilling through the studs to connect together before existing to outside. Last line was drained into my sink with it's own P trap.

I opted for the FH series which has automatic vanes that move up and down as well as side to side on it's own. It also has an optical eye at the bottom right corner of the unit that scans for movement within the room and focus the vanes at that location.

I have no experience with any other brands but for those that are considering the Mitsubishi units, I highly recommend them. Although I've only had mine for a week, I'm really loving it so far. It's super quite when it runs and heats up my 1600 sq. ft. basement shop from 55 to 65 degrees in about an hour. The 12 year warranty is a big bonus.

[Jack Frederick]

First off, follow the manuf installation instructions. These units depend upon air circulation to work so don't build them in to a confined space. Also, pay attention to the line set requirements. Some manuf have minimum one set lengths. .

[Mike Hollingsworth]

Jim, you can rout the refrigerant piping up down or sideways as you choose. The drain is the problem. Mshp's are excellent at dehumidification and in Buck's Cty, you will need plenty of it. A gravity drain is desirable as a result, so you will likely have to drill the wall for that. Check the manuf spec on your evaporator to confirm the piping layout. I use Fujitsu's as I know them best. I drill the hole on the left side and move the drain to the left side. That allows the drain line to exit the building directly and makes it future accessible at the connection and easy to deal with. Also the line set goes through that hole and lays across the back of the unit, again allowing easy future access. It is a machine. Build it so you can service it. Another big advantage of putting the drain on the left is that it makes it easier to close the unit down onto the mounting bracket. With the drain line laying across the back it is a classic example of 5# in a 4# bag. You end up shoving things around trying to get the unit to close down and frequently end up trapping the drain line. DO NOT be that guy. Therein lies madness Flooding condensate tray, standing water, mold mildew. Running the line set out of the wall directly on the rt kinds two blocks you for future access. If you choose to pump your condensate, Aspen makes some nice mini pumps, but I find them to be annoying. On the drain connection I have found the best way to deal with them is to Use a plastic barbed fitting with hose clamp X 1/2 or 3/4" mpt plastic fitting into the pvc female adapter.

I've done more than ten of these.
This guy knows what he's talking about.

[Peter Kelly]

I just got a 3 zone Mitsubishi 24k BTUH 20 SHEER system installed in my basement shop last week and I'm LOVING not walking into a 55 degree shop during the winter. I hired a Mitsubishi diamond contractor to install mine, My knowledge of HVAC is zero to none so I didn't want to mess with it. Although, now that I've seen how they did it, I wish I would have done it myself because it looked so easy. The one perk of having a Mitsubishi diamond contractor do my install is that Mitsubishi extends my warranty from 10 years to 12 years. The contractor ran all my copper lines up the walls and along the ceiling joist and all 3 lines exit the house at one location where the outdoor unit is. 2 of my condensate drain lines were ran along my walls, drilling through the studs to connect together before existing to outside. Last line was drained into my sink with it's own P trap.

I opted for the FH series which has automatic vanes that move up and down as well as side to side on it's own. It also has an optical eye at the bottom right corner of the unit that scans for movement within the room and focus the vanes at that location.

I have no experience with any other brands but for those that are considering the Mitsubishi units, I highly recommend them. Although I've only had mine for a week, I'm really loving it so far. It's super quite when it runs and heats up my 1600 sq. ft. basement shop from 55 to 65 degrees in about an hour. The 12 year warranty is a big bonus.

Thanks, am planning on getting the same for the upper floor of my house. Is this a P or M-series unit? What does the 12 year warranty cover? Parts? Just the compressor? Also, how did you locate a Diamond installer? Does the unit need to be purchased through one to get the extended warranty?

[Hoang N Nguyen]

Thanks, am planning on getting the same for the upper floor of my house. Is this a P or M-series unit? What does the 12 year warranty cover? Parts? Just the compressor? Also, how did you locate a Diamond installer? Does the unit need to be purchased through one to get the extended warranty?

Hi Peter, I want to say I have the M series since all my units have their model# starting with the letter MSZ. I can confirm this with my contractor tomorrow.

The 12 year warranty from Mitsubishi covers parts and compressor minus labor, my contractor offers 2 year labor coverage. He said 2 years is more then what most contractors will offer but he wanted his customers to go through 2 cooling and heating cycles just in case.

If you go through the Mitsubishi website and inquire about their units, they will have a diamond contractor in your area come out to provide quotes as well explain their product. All diamond contractors are trained by Mitsubishi, which is why they offer an additional 2 year warranty.

[Jim Becker]

Tim, how did you find a local HVAC tech to do the final work for you? The firms around here look at you like you have two heads if you ask for a "final install only" type quote. They want the whole deal or nothing it seems...

[Tim M Tuttle]

Tim, how did you find a local HVAC tech to do the final work for you? The firms around here look at you like you have two heads if you ask for a "final install only" type quote. They want the whole deal or nothing it seems...

I made a post on Nextdoor.com asking if anyone knew an HVAC tech that might be able to help me. I got a reply from a contractor who uses a guy on a lot of his jobs. Your best bet probably is to find a guy that will do side work or someone who works on his own.

[Bill Dufour]

A car ac guy should be able to do the simple connect and vacuum for a mini split. But they may not own the cheap adapter to connect the smaller service port used on mini splits.
I do not know how many car ac folks even do copper flaring. I think most all car connections are factory connectors with O-rings.
Bill D

[Jim Becker]

A car ac guy should be able to do the simple connect and vacuum for a mini split. But they may not own the cheap adapter to connect the smaller service port use don mini splits.
I do not know how many car ac folks even do copper flaring. I think most all car connections are factory connectors with O-rings.
Bill D

True, but there are warranty implications on who does/signs off on the install for many of the manufacturers. Having someone with proper certifications is helpful with that.

[Brad Adams]

As an HVAC contractor I wouldn’t quote a final install only either. I don’t think you guys realize how expensive it is to maintain and keep a business running with all the regulation we have with licenses, insurance, and everything else that goes with it.
Once we touch it we are liable.
As an example, many years ago, I installed a gas line to a vent free heater in a shed that was converted to a woodworking shop. The homeowner bought and installed the unit, I just installed the gas line. A year later I received a letter in the mail that my insurance company was contacted by his insurance company to pay for damages caused by mold. The guy kept the unit on all the time with no ventilation causing black mold due to all the moisture it put out. Had I not wrote on my invoice that the owner was warned of the dangers of running a vent free heater I would have had to pay the damages. Even then it took a lawyers letter to get them to back off.
Don’t tell me that you won’t hold me liable, it isn’t you that will do it. Your insurance company won’t bat an eye at trying to get out of paying the bill for damages without you even knowing about it.