Installing new mini split: tools and prep?

Reply

  #1  
Old 09-18-18, 02:31 PM
T
Member
Thread Starter
Join Date: Sep 2018
Location: usa
Posts: 16
Received 0 Votes on 0 Posts
Installing new mini split: tools and prep?

I'm going to wake this thread back up vs starting a new one, and just add to the discussion. I find myself in a similar position to the OP. I have extensive diy experience (flipped 9 houses with 4 historical restorations in the mix), doing all the work myself. While not HVAC certified, I have course credit hours from HVAC classes I took when i was younger, I wouldn't likely try and repair my own HVAC, but a mini split install seems pretty straight forward to me, especially since most of them come pre-charged now with 410a, so charging is not an issue.

That said, have been researching mini's for some time now and got the requisite quote from a reputable local HVAC dealer for consideration and comparison.

I have a small ranch style house (just shy of 1200 sq ft) located in the Willamette Valley in Oregon. The house was built in 1941, but has been since insulated and new windows by another owner. They seemed to have done a decent job. In the Pacific NW, we don't have the humidity issues that of back east (I lived in the mid-Atlantic 25 years). I.e., it cools off at night. When it gets into the 90's during the summer (i currently only have a gas heater, no air conditioner), it typically gets into the low 60's or high 50's at night. I find the house gets up to 80 during the day with everything closed up, but i can bring that down to 70 opening it up at night, so the temp change is 10 degrees, which strikes me as pretty decent insulation? We don't get too cold during the winter, so I consider this an ideal location for a heat pump.
Given our comparatively short spells of hot weather, i am more inclined to look at the HSPF rating than the SEER rating.
The local HVAC quoted me on a Daikin 9000 and 12000 btu (one at each end of the house) set up with a total price of $6700. I priced the exact units online @ $2744 and am guessing he gets them for less. I priced the cost for material to run two disconnects (breakers, wire, disconnect boxes) at ~$125. Pricing the cost of gauges and vacuum pump on Amazon, cost is ~$100. and if i want to go the route of a nitrogen pressure check, add another $100. All told, the diy project would cost ~$3000 vs $6700 pro.
I'm guesstimating if I want a warranty for diy, it will likely cost about $500-$600 in my area if I can even get an HVAC to do the line test and connect. Am guessing I can since places like Home Depot and Lowe's sell these systems and can connect people with HVAC contractors, am guessing some would be okay with me doing most of the work? Can also pay a higher price for a diy "Mr Cool" unit if i want the warranty.

The option i am seriously considering is buying one of the (Many) Chinese built units rebranded (and quality controlled) through western companies. There's quite a few of them out there now, many use Japanese or GMAC compressors.
I'm strongly considering Senville, a Canadian company, because their units are made for Canadian winters and they pay more attention to the HSPF rating (it seems) than their American counterparts. I can do a comparable efficiency (actually, the Senville units I'm looking at are higher rated Energy Star units). I can do the same set up, sans warranty, for an all in cost of ~$2000.

I'm leaning towards the last option with similar performance at about 30% of the cost. The $4700 difference could pay for a lot of repair work, if even needed. It could actually pay for replacement several times over.

Interested to hear other peoples thoughts?


Separated from...... Installing-new-mini-split-need-advice
 

Last edited by PJmax; 09-19-18 at 11:59 AM.
Sponsored Links
  #2  
Old 09-18-18, 02:49 PM
T
Member
Thread Starter
Join Date: Sep 2018
Location: usa
Posts: 16
Received 0 Votes on 0 Posts
quick p.s.
For those who have done their own mini install, did you do the nitrogen pressure check? I know some simply pull a vacuum with gauges and then let the system hold the vacuum for a time to check for leaks. If vacuuming to 500 microns, that seems like an adequate leak check to me?
 
  #3  
Old 09-19-18, 05:52 AM
jjrbus's Avatar
Member
Join Date: May 2010
Location: US
Posts: 325
Received 1 Vote on 1 Post
I don't do this to save money, I like to learn to do things and have a bit of experience from maintaining my cars AC systems. Doing my due diligence and extensive help from forums and watching every install video on the net. For a long lasting system a nitrogen test is a must, vacuum can seal leaks that pressure will open. A micron gauge is also needed and there are many reports of preformed flairs failing, Adding a quality flair tool to the list. These systems are running 500 psi, need to be done right.

I also noticed that the flair nuts on the preformed lines were much smaller and lighter than the ones supplied by Daikin. Speaking of the nuts unless you are doing this everyday for long lasting connections the nuts must be torqued to manufactures specs.

A VCRT, valve core removal tool also helps do the job right.

I bought a CRS mini split install kit which included everything needed except the micron gauge online for $300, also includes a flair gauge that for a non professional is another way to avoid failure.

I can't seem to get the hang of the fancy deburring tool in the kit so use my old one, care must be taken to not get debur chips in the lines.

Tool kit, micron gauge, nitrogen tank and gauge. Getting over $500 for tools, but can be sold once job is done. Tools can be bought and job done right or you can pay a service tech to do it right the second time. Seems like a lot of money but I have friends that spend that much on a single golf club, I don't play golf, I enjoy this more.

As a side note some of the videos on the net do not have a clue what they are doing!
 
  #4  
Old 09-19-18, 09:19 AM
T
Member
Thread Starter
Join Date: Sep 2018
Location: usa
Posts: 16
Received 0 Votes on 0 Posts
Thanks jjrbus.
jjrbus also sent me a link that show how to flare and connect lines for a mini split. Good into, found the flare tool he used, not to bad on price.

I already have a torque wrench. I've found vacuum pump and gauges for a total of $100. The only thing i get stuck on is the micron meter, they're pretty expensive but important. Here's a good video on pulling a vacuum on a system.
 
  #5  
Old 09-19-18, 12:00 PM
T
Member
Thread Starter
Join Date: Sep 2018
Location: usa
Posts: 16
Received 0 Votes on 0 Posts
For those of you following this discussion, here's a few more item/comments.

As jjrbus mentioned, a micro gauge is pretty important when installing a HVAC system, of any kind really. For those who are not familiar, the reason is to remove moisture. Refrigerant is dry. HVAC systems utilize a metering device (e.g. expansion valve) that takes liquid refrigerant from one end of the system and, sort of like a nozzle on a hose, turns it into spray. Moisture can freeze and clog the metering device, just as one example of damage it can do.

Mini Splits seem to only have one service valve for vacuuming, this is because the metering device is located in the outside unit, so the vacuum is not impeded by it when just drawing from one side. The micron gauge is to measure vs guessing that the system is truly vacuumed. Most pros i am seeing recommend vacuuming down to 500 microns. Here's a micron gauge that looks reasonable to me and has good reviews.

The other tool jjrbus mentions is a VCRT. I believe he is referring to a tool for removing schrader valves? I found this one for about half the price of most on Amazon. Not a tool i'd use a lot, has good reviews and seems adequate to the task.
 
  #6  
Old 09-19-18, 12:01 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 59,772
Received 1,192 Votes on 1,103 Posts
Welcome to the forums.

Although they were on the same topic..... the thread would become too long with this one attached to that one. Please keep in mind that we don't discuss charging methods or pressures here.
 
  #7  
Old 09-19-18, 06:14 PM
T
Member
Thread Starter
Join Date: Sep 2018
Location: usa
Posts: 16
Received 0 Votes on 0 Posts
Thanks PJmax,
And got it re charging, I understand. Good thing about the mini splits is they come pre charged, so that is not an issue for me. I'd get a certified HVAC person if it came to that.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: