Any HVAC Experts On Board? Lennox?

   / Any HVAC Experts On Board? Lennox? #1  

npalen

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Have a new Lennox mini split AC/Heat Pump installed for our 12' x 14' sunroom that has glass on three sides. The problem is accurate control of temperature as it has to get two to three degrees above the set point before the AC kicks on. Then it will freeze you out until it gets a couple degrees below the set point before shutting off.

The unit can be "controlled" with the sensor in the inside air unit or the remote when set to "follow me" mode but the problem occurs with either. Had similar issue in heating mode this winter although the unit did heat well even with outside temp of -20F.

I have tried adjusting the parameter called "F7 cooling temp compensation" which the manual for the remote describes as being related to "stratification", but that doesn't seem to help.

Just wondering if anyone might have some insight here as I do appreciate feedback.
 
   / Any HVAC Experts On Board? Lennox? #2  
How many btu is the unit? It might be that ur unit is oversized for the room. But u can google sizing of heat pumps and do the calculations yourself to determine if that is the case.
 
   / Any HVAC Experts On Board? Lennox?
  • Thread Starter
#3  
Forgot to mention, it's a one ton (12K BTU) and I suspect it is oversized. The installer/dealer suggested an 18K BTU but looking at the calculations beforehand suggested that even the 12K would be plenty.
He felt that all the glass would require more BTU's
 
   / Any HVAC Experts On Board? Lennox? #4  
is your thermostat set in a good place?
Maybe the wall it's on gets heat from the sun, or just has a lot of residual heat in it.
The air gets cold, you get cold, but the wall and thermostat gets cold later.

I've had this problem a couple of times.
 
   / Any HVAC Experts On Board? Lennox? #5  
I'm thinking minimum run and rest times.. ? Also, a lot of newer t-stats like to have the anticipater settings at 1.5* - 2* instead of the more normal .75* - 1*. Double check that..

edit: menagerie-manor beat me to it. Phone call while trying to edit :)
 
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   / Any HVAC Experts On Board? Lennox? #6  
As suggested the T-stat location can be an issue but also look at the thermostat instructions and see if the stat has an adjustable anticipator which sets the rate of temp rise or drop and either turns the ac on or off base on the temp change rate.
 
   / Any HVAC Experts On Board? Lennox? #7  
Many air handler blower motors have low, medium and high settings that are controlled via a switch or “speed wires” (located at the blower, not the thermostat) that can be connected depending upon the season.

Your installer should not object to testing fan speeds for you to find the most comfortable setting.
 
   / Any HVAC Experts On Board? Lennox?
  • Thread Starter
#8  
This is the service manual for the remote control. I have adjusted the F7 parameter to -2 which seemed to help a little in narrowing the band.

The frustrating thing is that this is an expensive unit that has the inverter technology controlling the compressor which supposedly will smooth the operation.

I've taken amp readings on the 230VAC supplying the unit and am amazed at the low power consumption of 2.0 amps or less when cooling. We have only had 90F max days so far so will be interesting how it handles long 100F days here in Kansas.

I've tried a number of "tricks" by placing the remote in various locations for temperature sensing as well as using the sensor in the wall air handling unit rather than the remote.

I believe there is an ambient temp sensor in the outside unit that supposedly anticipates the amount of heating or cooling needed.
 
   / Any HVAC Experts On Board? Lennox? #9  
I believe there is an ambient temp sensor in the outside unit that supposedly anticipates the amount of heating or cooling needed.
I'm not familiar with Lennox's mini splits, as they are private labled made by someone else, and it's hard to keep track of who they are using (use to be Gree sp? last I heard was Media) but you are probably right about the outdoor sensor as I know Daikin, Fujitsu and Mitsubishi all have outdoor temperature sensors.

If you paid a contractor to install the job right the first time, may I ask why hasn't the contractor taken care of the issue?

Even the cheapest mini split you can find (which I wouldn't touch with a ten foot pole) has a inverter compressor.

Again, not familiar with what Lennox is now using, but generally, on a mini split, you can figure the compressor will run at 70% less full rated capacity, so if you have a 12k indoor unit, I doubt the unit is oversized as it should run as low only needing 3,600 BTU/h on a regular basis.

Installing contractor should call lennox, set up a online call meeting with the service tech at a designated time that he is out there to look at the operation, and they should be ready to take his call and go over any possible issues. Even going by what I call the "goodman" load calc, a 12k mini split seems like it should work.

There is a whole set of possible issues which you shouldn't be responsible for IMO and the installing contractor should take care of.
 
   / Any HVAC Experts On Board? Lennox?
  • Thread Starter
#10  
I'm not familiar with Lennox's mini splits, as they are private labled made by someone else, and it's hard to keep track of who they are using (use to be Gree sp? last I heard was Media) but you are probably right about the outdoor sensor as I know Daikin, Fujitsu and Mitsubishi all have outdoor temperature sensors.

If you paid a contractor to install the job right the first time, may I ask why hasn't the contractor taken care of the issue?

Even the cheapest mini split you can find (which I wouldn't touch with a ten foot pole) has a inverter compressor.

Again, not familiar with what Lennox is now using, but generally, on a mini split, you can figure the compressor will run at 70% less full rated capacity, so if you have a 12k indoor unit, I doubt the unit is oversized as it should run as low only needing 3,600 BTU/h on a regular basis.

Installing contractor should call lennox, set up a online call meeting with the service tech at a designated time that he is out there to look at the operation, and they should be ready to take his call and go over any possible issues. Even going by what I call the "goodman" load calc, a 12k mini split seems like it should work.

There is a whole set of possible issues which you shouldn't be responsible for IMO and the installing contractor should take care of.


Your feedback is greatly appreciated. Good to know about the 70%.
Part of the problem is this is only the second mini split the dealer has installed. He is responsive but a big part of the problem is Lennox support.
He had Lennox on the hold line for over an hour the day of installation with a question and never did get to talk to a tech. Also, my understanding is that Lennox doesn't provide adequate written service info to their dealers.

I told him that I would try adjusting the cooling temperature compensation which I did and he will call Lennox when I get back with him with the results. He is a good dealer, it's just hard to get info from Lennox.
 
   / Any HVAC Experts On Board? Lennox? #11  
Your feedback is greatly appreciated. Good to know about the 70%.
Part of the problem is this is only the second mini split the dealer has installed. He is responsive but a big part of the problem is Lennox support.
He had Lennox on the hold line for over an hour the day of installation with a question and never did get to talk to a tech. Also, my understanding is that Lennox doesn't provide adequate written service info to their dealers.

I told him that I would try adjusting the cooling temperature compensation which I did and he will call Lennox when I get back with him with the results. He is a good dealer, it's just hard to get info from Lennox.
Just remember, the guy that knows his ***** on the equipment doesn't work for Lennox, but the manufacturer of the re branded Lennox equipment.

Technical support by Lennox can be regional. Sometimes it's who you know to call. That said, since Lennox doesn't actually make their own mini splits, not certain how they break the technical flow chart for that brand on who gets the call on their end and who those calls go to as I've never dealt with them for mini splits.

Generally when it comes to mini splits, you need to deal with a guy that either works with the manufacturer themselves, or someone who specializes in Mini Splits working for the "sub brand" (in this case Lennox).

I can tell you for a fact and first hand experience, when dealing with Daikin, Fujitsu and Mitsubishi, if the dealer knows what he's doing, he's going to call tech support (direct to that brands tech department) ahead and schedule an appointment when he or his guys are out on the job (generally 1/2 hour after the appointment on the job, so you have time to run the diagnostics and you can start going over the system operation).

I'd rather deal straight with the manufacturer than the sub brand people myself.

Carrier / ICP brands = Toshiba (or they may have changed because I know ICP is now using Gree)
Lennox brand = Media (or they may have changed)
York brand = Gree for residential
Rheem brands = Fujitsu
Trane/American standard brands = Mitsubishi

Word of advice, tell your lennox dealer he should just deal with Daikin, Fujitsu or Mitsubishi and be done with it. That said, regional support with either 3 I mentioned can be different on the contractors side.

EDIT - How old in age is your dealer? Only his second mini split system??! Inverter systems is where everything is going to be at 20 years from now (or sooner), added you'll end up using a inverter compressor for coils on top of gas furnaces and air handlers (already out now). I can't believe that if he already has used Daikin, Fujitsu or Mitsubishi he would of went to Lennox for a private lable brand.

Think about this... Lennox use to use Gree, now they are using Media (or perhaps someone else). Where do you get the parts 10 years from now if it was made by Gree and Lennox is no longer using Gree? Part of the problem on older private labled systems is just trying to figure out who actually made it if you aren't familiar with the nomenclature.

On a sidenote, Far east countries who make mini splits don't use a standard serial number like the Americans do that specify exactly when and where it was made. Seriously. Gave Mitsubishi a serial number for a replacement compressor. They asked me what year it was installed. Told them I had no clue but the serial number should get them in the ballpark. Nope, it was either made in 2001 or 2011, I needed to know the install year for them to look up the part because the parts could be different.
 
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   / Any HVAC Experts On Board? Lennox? #12  
I wish him the best. It has been my experience, Tech support is lacking throughout the industry
 
   / Any HVAC Experts On Board? Lennox? #13  
I wish him the best. It has been my experience, Tech support is lacking throughout the industry
It's who you know and whose cell phone do you have, added you need to ensure you have your data correct and together, other then telling the techincal service guy "everything looks good". FIRST thing I ask a guy myself on a unitary split product system is what's your static pressure and CFM's. The answer is generally always "GOOD!". From a technical standpoint, "GOOD!" means jack crap. Know why they say "GOOD!"? Because they never check because what's more important to them is what their gauges are telling them.
 
   / Any HVAC Experts On Board? Lennox?
  • Thread Starter
#14  
Five degrees between where the unit starts to cool and where it shuts off seems like a very basic problem that should be fixed with a simple parameter adjustment.
I think the problem is that Lennox doesn't supply this info to the dealers.
 
   / Any HVAC Experts On Board? Lennox? #15  
The irony is with all this trouble shooting, the one question not asked / answered is how high is the wall mount unit off the floor (hot air rises, cold air falls)? Also, how far is the wall mount unit away from the opposing wall and what is the throw distance of that unit (should be found in it's tech spec guide).

Honestly from my experience, full glass enclosures can be the most trickiest. Simple solution is it's the equipment's issue, more harder is the environment the equipment is in.

Personal experience in NC, commercial add on to a building, full glass enclosure which had no conditioned space below the add on office space. Job being done in February when it gets cold even in NC. Before the equipment was installed, guys showed up in the new office space at 0800. It was about 35 degrees outside that morning (that's cold for southerners when I could still be wearing shorts LOL). The new office space (without HVAC) was already over 80 degree F that morning in that office space. I didn't plan the job, but it was a "oh *****" moment on the guy who ordered the equipment when everyone looked for the actual low ambient cooling capacity. End of the day, brands were switched out to guaranty low ambient cooling. Point being, sometimes it's not the equipments issue but an envrionment issue.

Never spent much time in Kansas, but had spent some time in Oklahoma. I'm guessing the temps between winter and summer can be extreme?
 
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   / Any HVAC Experts On Board? Lennox? #16  
Five degrees between where the unit starts to cool and where it shuts off seems like a very basic problem that should be fixed with a simple parameter adjustment.
I think the problem is that Lennox doesn't supply this info to the dealers.
I have 3 pioneer mini splits. My understanding and experience is they have a 4 degree swing on-off.
Mini splits are designed to keep you comfortable and control humidity by running continually. They do not cycle like typical split systems.


Mini splits are quiet and energy efficient, however they are poor at circulating air.
Air circulation is important for even cooling and comfort.

I run a fan at all times in the rooms that have mini splits. 2 have ceiling fans and one I use a small Honeywell fan.

Adding the air circulation helped my comfort considerably.

Also, the Auto system selection is worthless for comfort. Only good for vacation. Be sure to use "cool" or "heat" setting.
I do use auto on the fan speed.
 
   / Any HVAC Experts On Board? Lennox? #17  
Also, the Auto system selection is worthless for comfort. Only good for vacation. Be sure to use "cool" or "heat" setting.
I do use auto on the fan speed.
Fact is both Fujitsu and Mitsubishi have a GREAT feature for "auto" between heating and cooling for single zone systems. When it comes to multi zones, Fujitsu has a 30-45 minute delay which can upset customers, and with Mitsubishi its not even possible to set a multi zone on auto unless you use their app software, which can confuse anyone to actually enact the auto feature and it's not worth even trying to go over what you need to do with the homeowner.

At least the unkown Chinese factory used an American name for "Pioneer" 😁 Seems they are imported under Parker Davis HVAC international. Sometimes you do get what you pay for.
 
   / Any HVAC Experts On Board? Lennox?
  • Thread Starter
#18  
Yes, temperatures in Kansas can range from -20F to +120F.


Wondering if this universal mini split controller might be an answer. Supposedly it shuts the unit "off" when set temp is reached and "on" when it needs to heat or cool. My question would be if shutting the unit completely off is a good thing. Anyone with experience with these? They are also wifi controllable with the app for what that's worth.

Edit: After further reading, it sounds like the controller does not actually turn the unit on and off but actually cycles the compressor for heat or cool and also controls the fan speed.

I have 3 pioneer mini splits. My understanding and experience is they have a 4 degree swing on-off.
Mini splits are designed to keep you comfortable and control humidity by running continually. They do not cycle like typical split systems.

Not sure what you're saying above. How does one get them to run continually rather than cycle?
 
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   / Any HVAC Experts On Board? Lennox? #19  
Not sure what you're saying above. How does one get them to run continually rather than cycle?
If you're driving a car, what if you had 160 gears in a automatic?

When you drive a V8, do you get better gas mileage if your in the city stoping and going at every traffic light, or do you do better cruising at 70 at a constant speed?

If your riding a bike, is it easier or harder going uphill and down hill on that bike with a 3 speed vs a 10 speed?

Same concept with inverter compressors.

Take my word for it, stay away from mobile apps on your mini split system. With a mobile app, you're now including a whole set of possible issues that has nothing to do with the mini split system. Set it for the temp you want, and let it run...
 
   / Any HVAC Experts On Board? Lennox?
  • Thread Starter
#20  
Set it for the temp you want, and let it run...

That would be fine if there was not five degrees fahrenheit variance. That's going from uncomfortably warm to uncomfortably cold.

Take my word for it, stay away from mobile apps on your mini split system. With a mobile app, you're now including a whole set of possible issues that has nothing to do with the mini split system. Set it for the temp you want, and let it run...

Can you elaborate? The Cielo controller can be used locally as well as via wifi. Are you saying there are possible issues with either method or just the mobile app and wifi, and what are the issues?
 

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