A lesson learned from a recent multi-zone mini split installation.
I recently installed a two zone mini split heat pump in my auto mechanic’s shop, (see the next article about what I call “trade bartering”). It was a fairly straight forward job…one 9K evaporator in a small customer waiting area and one 12K evaporator in an office with three desks. The waiting room evap is mounted on an outside wall so lineset, cord and drain runs were quite easy. The office evap was on an interior wall and required the installation of a condensate pump…I used the Aspen Mini Blanc, (see a following article for more detail). Lineset, cord and drain runs were made somewhat easy as I had access to an attic space above the office which had direct access to the same outside wall that the waiting room evap was on and the outdoor unit ODU was just below.
When I went to my local supplier for installation accessories like the linesets, disconnect and whip, I was given a non-fused disconnect. I have always been a “belt and suspenders” guy so I have preferred using a fused disconnect but when I requested one, I was told that my supplier only had the non-fused type. I shrugged my shoulders, accepted what they had and didn’t think much of it again.
The equipment installed with little trouble and I was ready to power it up. This was the week of 7/26/15 and the local New York weather report for the week was calling for record heat by mid-week so the installation of the AC could not have come at a better time.
Well, everything went downhill when I powered up the system for the first time.
I placed the pull-out head in the disconnect box and the system began operating…but not for long. The evaps powered up, fans were running and the indoor unit IDU LED screens were indicating the compressor was ramping up, (inverter compressor)…so far so good.
Less than 5 minutes into initial start-up, the system shut down…EVERYTHING was off.
I checked for power at L1 & L2 of the ODU…I had 234 volts.
I pulled the disconnect head out and then back in to reset the power…I also pulled the top cover off the ODU so I could view the LED screen of the ODU to see if it was displaying an error code. Once the disconnect head was replaced, the ODU LED should 00 for exactly 30 seconds, then a P6 error code appeared just before the unit shut down completely. I again checked power to the ODU at L1 and L2 and once again it should 234 volts.
According to the equipment manufacturer, P6 error code represents, “IPM module protection”. The first step in the service manual’s diagnostic chart for the P6 error code was to check the ODU for correct voltage…220 – 240 volts. Once again I confirmed I had 234 volts at L1 and L2 of the ODU.
I consulted directly with the manufacturer in China, (I am lucky enough to have contacts within the major Chinese manufacturers of mini splits). I was told to replace the IPM…and if that didn’t work, replace the main board…and if that didn’t work, replace the compressor.
I kept at it, exhausting what I thought were all possible causes for this problem, less replacing boards and the compressor.
I was out of options when for reasons I can’t fully explain, when replacing the disconnect pull out head for now what was about the 50th time, I decided to hold it in place…putting pressure on the head as I held it.
The system ran!
As soon as I let go of the disconnect head, thirty seconds later the ODU displayed P6 and the system shut down.
The disconnect was the source of my problem…THE DISCONNECT!
I turned off power to the disconnect via the breaker and then began to disassemble the disconnect box. What I found was that when the box was assembled, the stationary portion of the disconnect was torqued so that when I placed the pull out head in it, it made a poor connection…it was loose!
I reassembled the disconnect without torqueing and now the pull out head was solidly in its place.
I powered up the system and voila…it ran like a champ!
In all my years I never had a disconnect be the source of such a problem!
There were clues right from the start that I should have paid closer attention too…
#1) I never felt the disconnect pull out head was seating properly…it always felt a bit loose.
#2) Each time I would replace the pull out head, I would hear a crackling noise…clearly and indication of a poor connection being made.
#3) One time, after pulling the disconnect head out, I noticed the copper tabs which make the connection in the box were now black…another indication of jumping voltage, (poor connection).
#4) The P6 error code was telling me what I needed to know but I wasn’t listening…neither was the manufacturer for that matter. The IPM was in deed being protected as designed. Remember what the service manual had me check first…voltage to the ODU!
Here is where sometimes it gets tough to clearly see what is right in front of you.
Remember every time the system would shut down, I would check for voltage at L1 and L2 of the ODU and every time without fail I had 234 volts. The problem is I was taking that reading AFTER the system had shut down…there was NO load and the system was pulling NO amps in that state! Once I reset the power at the disconnect, had I taken a reading at L1 and L2 during the 30 seconds that the system was trying to start, I would have seen the problem!
Something I call “Trade Bartering”.
I have completed two mini split installations at the shop of my auto mechanic, (and friend). In both cases NO money changed hands between us…we did a little old fashion bartering!
Let me first explain why such an arrangement with my auto mechanic would appeal to me…
My wife and I have a total of 8 vehicles. We are car people for sure and 5 of the 8 are hot rods, dune buggies and a British sports car. The other three are our everyday drivers…my Ford Transit Connect, an old Chevy Blazer that we use as a “beater” and affectionately call it “Murphy’s truck”, (Murphy is our 11 year old Basset Hound), and my wife’s Cadillac CTS.
I do most of the work on the 5 fun cars myself but every once in a while something comes up that is out of my wheelhouse and I need help from our mechanic who after more than 25 years of doing business is a friend as well as business associate.
Well, about a year ago I noticed one of those nasty portable AC units in my friend’s office…and I had a thought. I told him I would install a single zone mini split to cool, (and heat), his office in return for a mutually agreed “store credit” for my wife and myself…he agreed!
Well, a year went by and he was doing yet another renovation to his shop…an upgrade to the customer waiting area and a new office area where customers first come in and talk with an advisor, (this is the job I just wrote about in the previous article).
I love that skilled tradespeople can barter like this for mutually beneficial results. Think about this in your own world…we all have buddies who are electricians, auto mechanics, skilled construction workers…all who can benefit from your skills and vice versa.
I know what you thinking…”this is a good way to LOSE a friend”.
Yeah…maybe…but remember, no money is changing hands and all that is being exchanged is your skills and labor.
Think about it next time you need something done by a fellow tradesperson…I think it’s a cool alternative to writing a check!
A few new items I used on my latest mini split install.
I may have discovered the recipe for a flawless flare each and every time…
First, I use the Yellow Jacket 60278 deluxe 45 degree flaring tool. The 60278 is good for tubing diameters from 1/8” to ¾”. It is specifically designed for R-410A systems.
The best feature of the 60278 is the automatic tube height gauge which does not let you go beyond an integral stop, making sure your flare is perfect every time.
You can see the Yellow Jacket 60278 at this web address…
The next ingredient for a perfect flare is Nylog by Refrigeration Technology. Now keep an open mind here because what I’m about to tell you will run counter to everything you ever learned about making a flare.
Nylog is a gasket, thread sealant and assembly lube which is HFC refrigerant compatible. It is a viscoelastic liquid derived from refrigeration grade lubricants. You place Nylog directly on the face of the flare as well as on threads and the back of the flare. Placing anything on the face of the flare has been a big NO-NO but not with Nylog.
I use Nylog Blue for my R-410A mini split systems. It creates a seal that will never dry out and / or harden and will not clog.
You can see more about Nylog Blue at this address and click on the YouTube link to see a video about it…
I have been a big fan of the Aspen Mini Aqua condensate pump…you have probably seen the video I created on the installation of the Mini Aqua in a mini split evaporator on the ESPCO website and my LinkedIn profile.
My last mini split install, (the one in the auto repair shop I described earlier), called for one of the evaporators to be placed on an interior wall. I decided to try the Aspen Mini Blanc. The Mini Blanc does not integrate into the evaporator like the Mini Aqua does, but rather sits just below the evaporator. The kit comes with everything you need to install the Mini Blanc but the discharge tubing…you will need to provide ¼” diameter clear tubing.
The voltage requirement for the Mini Blanc is 100 – 250 volts so throw anything at it within that range and it will work…PERFECT for inverter systems!
Like the Mini Aqua, the Mini Blanc powers off L1 & L2 of the evaporator. The pump also has a normally closed switch that I placed in series within the communication cable from the ODU to the IDU. Now this too runs counter to what most mini split manufacturers will tell you about the communication cable between the ODU and the IDU…generally, they want an uninterrupted run of cable between the two. I can tell you definitively that as long as you make your connection on the pump and the communication cable with a butt type splice connector you will be fine…DO NOT USE WIRE NUTS! This wiring configuration will stop the IDU from operating should the pump fail…and that’s a good thing!
You can see the Mini Blanc at the following address and watch the video on the site as well…
A BIG move for me!
Approximately three months ago I accepted the position of Director of Training for Watsco, Inc. of Coconut Grove, FL. You may not know the Watsco name but they are the largest distributor of HVAC equipment in North America. Watsco consists of five major subsidiaries…
East Coast Metals
Watsco also has several E-commerce based businesses such as Tradewinds and AC Doctor. Their stock is publically traded on the New York Stock Exchange, (WSO symbol), and have annual sales exceeding $3.9 billion dollars.
As the Director of Training I will be working with the training departments of each of the subsidiaries as well as developing corporate training initiatives…the first of which is based on Variable Refrigerant Flow VRF technology. It is my goal to work with our VRF vendors as well as our internal staff to develop the industry’s best VRF training!
As a result of joining Watsco, my work at ESPCO will now be limited to this newsletter. I will keep the ESPCO website active by using it as a vehicle to promote Watsco sponsored training events around North America as well as a place to post new videos related to my activities and products within Watsco.
This is an exciting time for me…an opportunity to help build a training vehicle of unprecedented and unlimited growth with a team of the best trainers our industry has to offer…WOW!
I haven’t forgotten the next installment of my five part series of articles titled, The five most common statements you hear about Variable Refrigerant Flow VRF systems….truth or urban legend? The next installment will be addressing VRF training and to that end, I have been attending VRF training events conducted by the major VRF manufacturers all around the country. In the interest of fair reporting, I still have a few more to attend and I want to have as much research completed as possible before I write the next installment. My goal is to have this for you in my next newsletter in October.
See you soon!
The views and opinions expressed in this newsletter are those of the author and do not necessarily represent those of ESPCO’s sponsors and training partners.