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Product Information => Product Reviews => Topic started by: lighthunter on December 16, 2021, 11:29:16 am

Title: Mini Split
Post by: lighthunter on December 16, 2021, 11:29:16 am
Hi all! During summer months, any extra solar panel power goes to the 100gal hot water heater. Works great as it can carry a couple cloudy days and good sized dump load in two stages. During winter i dont need it as the outdoor wood boiler heats the water. Air source heat pumps boast a 3 to 1 gain over electrical resistance heating in watts per btu out. I think thats a pretty optimistic figure strictly for above freezing outdoor temps.

So i finally bit the bullet and installed this a week before it turned cold.
R410A, 12000btu 1 ton, 5.3Amps at 240VAC cost $750.

It does what it says do so im happy. Id say it works darn well just above freezing. 5 deg below freezing and its busy with defrost cycles a lot. Right now its 25 deg, and solar panels have plenty so its busy heating.

I guess if thats your need its real nice, i think it would take a few years to pay for itself. They are immensely complicated so i cant think this will be running 20 years from now the way old fridges do. Its got a 3phase inverter for variable speed refrigerant pump and the same for the indoor air handler and outdoor fan. Not to mention electric refrigerant reversing valve maybe even variable plus pressure transducers and temp sensors etc all over. 

Not complicated to install, refrigerant came inside. The liquid and vapor lines are different sizes but dont expect traditional pressures if your used to older refrigeration systems. The larger vapor line is indeed 125-150 psi in cooling mode but in heat mode the same line becomes 400psi. Once you install you can move it if you have to without loosing refrigerant. There are two valves one on each line and in coolling mode you can shut the liquid valve and leave pump on to evacuate the vapor side. Then shut the vapor valve and turn it off, esentially putting the jack back in the box. Of course a vacuum pump is needed same as the install to remove contaminants from lineset. They do sell canned nitrogen to puff them out if preferred.

All in all, im happy with it but it wont be a great idea for everybody. I can see more and more new homes with these covering the entire heating and cooling as a cheaper install and cheaper to run than traditional systems until the temp drops to -25 (-32C) then people will freeze to death.





Title: Re: Mini Split
Post by: Pete on December 16, 2021, 04:34:17 pm
Hi LH, it sounds like a good system.
How realistic are the power draw figures on the unit?
I have been wondering about fitting a heat pump type unit to our place as it would be better environmentally than burning wood.
Sounds like the unit you have is rated at around 1200 watts, that would be fine for us, depending on how long it runs for each day.
Our temperatures are much milder than yours, we never get below about -3 degrees C at night. Winter days are around 1 to 3 degrees at a minimum, so the unit should not freeze up.
It sounds like they don't like very cold temperatures, not so good if you prefer to stay defrosted.
Let us know how it goes, and what sort of power consumption it has.
Pete
Title: Re: Mini Split
Post by: lighthunter on December 17, 2021, 12:16:04 am
Hi Pete!

The 5.3 Amps @ 240V is a measured value on max heat at 34 F (1C),  they list the max power current as 6.1A and rated 4.9A.

This thing really pushes heat above freeze point. The real question is, at what temperature does the coefficient of performance drop to 1. This is where youd be better off switching on a resistance heater. The sales flyer says it will heat down to -13F, ok maybe it will. I have only seen it working at 25 so far and it does ok minus the frequent 5 minute defrost cycles. Realistically i cant see it as a heater if outdoor temp hits 0F (-18).  They dont like to print the COP vs temp graph. 

So it works, just less so as you go below freezing which makes sense as your really trying to get heat from an ice cube at that point. I would hate to try to run it on battery to heat a home though. I suppose anything is possible but my bank couldnt do it.

It is interesting to note that a 9x7 foot garage door framed with thick clear vinyl will produce a comparable amount of heat with considerably less up front cost but a window that size may not always be an option.
Title: Re: Mini Split
Post by: Pete on December 17, 2021, 03:00:00 pm
Thanks for that info LH.
We never run heating at night, our house if tiny, so once it is heated up it stays warm enough for a long time.
We open doors when the house gets to 22 degrees C, that is too hot for us.
So I would only use a heater in the mornings and sometimes in the middle of the day in winter.
Cheers
Pete
Title: Re: Mini Split
Post by: lighthunter on December 24, 2021, 01:37:21 pm
Yeah, sounds like your weather would work real well with one of these.  Today i took this photo at 12:30 PM 38°F (3.3 C) . I mustve caught it just before a defrost cycle.
This is side view, the back is the large surface area of radiator, it had same ice pattern.
I think defrost is triggered by outdoor air temp, coil temp and a timer and software.
As expected, the heat output varies a lot based on the outdoor temp and ice packing the coil. They mitigate the effects of this by ramping the fan up and down on the indoor HX, this gives a pretty constant discharge air temp but at varying flow.

With the mild temps weve had this year so far I'm very happy with it.


Title: Re: Mini Split
Post by: Pete on December 24, 2021, 03:06:00 pm
Thanks for the update LH. As we are now into summer here heating is not an issue. We very rarely need cooling as most Summer days are less than 25 degrees C. We don't really like it when it gets over 20 degrees C, but then our blood has thickened from living on the mountain .
I am toying with putting in another panel rack near my ground mounted panels, as the panels are so cheap these days. Then I would have enough power for winter use of heating.
We get quite a lot of foggy, cloudy days in winter. Some solar power still happens but not a lot.
I will let the idea rattle about in my head for a while.
Have a great time and enjoy your winter.
Cheers
Pete
Title: Re: Mini Split
Post by: lighthunter on December 27, 2021, 11:14:49 pm
Im jealous of your season Pete! Its 10F -12C 85% humidity dewpoint 7° right now... brrr, the heat pump is drawing about 1100W 4.6A warm breeze from the vent, definitely not hot but it holding well insulated 3 vehicle garage about 50F. I set timer to come on at 11AM today and it will turn off at midnight, so 13 hrs of run time.
I cant deny this thing works but an 1100W resistive heater would compare in these conditions for sure. If you think about it, this poor thing is making ice cubes outside and then having to melt them into water. That phase change in these outdoor temps takes significant lost energy. Its hard to get a grip on what conditions make it senseless to run. That point is some combination of relative humidity and 10-20F outdoor  temperature.
The rule of thumb for disharge temp is 110°F + ambient which would be 120F.   By comparison, when my boiler water gets down to 120 the radiators are not putting out a lot of heat.

Definitely not complaining, just clarifying the below freezing performance in high humidity is marginally better or equal to resistive heating.
Title: Re: Mini Split
Post by: lighthunter on December 31, 2021, 06:51:39 pm
Hi all!  I know in previous posts i was not optimistic about cold weather heating with this 12kbtu heat pump.

After using it hard for a month i gotta say it works great!  The heat pump has maintained the garage at 40°-52°F (8°C) during 7°-20° (-10C) outside temps with heavy cloud cover and running continuously. Tstat set @80F. Current is right at 5A 243V. Defrosting every 40 to 120 minutes. Attached is a photo of the ice it has melted from the coils lately, 92% humidity last night. Id say more than 5 gal ice there.

 A 1200W electric heater produces about 4100 btu/hr. Im fairly sure its outputting twice that judging by garage temp. I shut it off for now and turned on a 5400 btu unvented propane burner so will see what happens to the garage temperature. The doors have been used very little, maybe once/day so will be fairly good comparison.

All in all its a win for heating with electricity. With mild outdoor temps, the cost per btu is very close to propane, maybe cheaper in some cases. As hard as the poor thing works to heat i would think longevity may not be that great but who knows. So far so good.

(Update)

After running the propane 5400btu heater last night instead of heat pump, the garage temperature dip at night was 5 degrees, very similar to the heat pump so that means under 10°F (-12°C) outdoor  conditions we arent doing a lot more than resistance heating, maybe x 1.3 at best. Why this is important? Well, in those conditions, why wear it out when theres no gain? Use a simple resistive heater or propane in those conditions. So my (at a glance) conclusion is... A 19 SEER 9.5HSPF air source heat pump will do you well as a heater from 25•F.
(-4°C) on up and i expect cooling will be fantastic. Happy New Year!
Title: Re: Mini Split
Post by: Pete on January 01, 2022, 05:05:59 pm
Hi LH sounds good. I would much rather use Solar power than Gas to heat our place.
At this time of year we don't need to heat the place at all. We are in the middle of 4 days of what for us is hot weather (25C)
Looking forward to it cooling down, we both much prefer the cooler weather, 15C and down is good for us.
In winter the house is heated at the moment by wood, we open doors if it gets to 22 C inside.
The idea of a heat pump is still rattling about in the brain box.
pete
Title: Re: Mini Split
Post by: lighthunter on January 15, 2022, 08:48:12 pm
Hi!  Since its been so cold i havent used the heat pump much but today it got up to 14F (-10C) and plenty of sun (after removing 10" snow from panels), I turned it on and it impressed me again. It wasnt a ton of heat but it was certainly more than a 1200w electric heater.  I shut it off again at 5pm at 8F(-13C) when sun went down but it was still heating a fair amount and the garage temp had raised from 40F to 53F so it defenitely did some heating.

To be clear, if you want to spend the money, they make units like Cooper&Hunter that have an hspf of 12 and will heat down to -22F for $1269. There are of course units that cost less than this Pioneer at around $500. But they dont even have an hspf rating. So be aware, they are not all created equal.
Title: Re: Mini Split
Post by: lighthunter on January 16, 2022, 04:37:49 am
I finally found some comparable information, below is the AHRI label for a slightly better heat pump than the one i have also made by Pioneer, it also costs $1058 whereas mine was $750 and has HSPF4 rating of 9.5. The one below has hspf of 9.8. So if you can find this information it helps compare apples to apples before you make a decision. Unfortunately it appears like those that have the rating cost substantially more and arent necessarily better.
Title: Re: Mini Split
Post by: lighthunter on January 29, 2022, 11:00:29 am
Update: Hi all!

 For solar heat nothing beats a window but for heating with RE electric and temps above 14°F (-10C) air source heat pumps are the way to go.
I can heat a 3 car garage to 50°with 1200w of electricity. By comparison, a 1500w space heater barely effects the garage temperature.
Lessons ive learned, do not mount on a ground pad like many install photos show.  Need outdoor unit off the ground 6" to 24" to prevent leaves and or ice buildup.If you intend to do a fair amount of heating mount on sunny side of your house, it makes a difference during defrost.
Title: Re: Mini Split
Post by: Pete on January 29, 2022, 03:03:13 pm
Thanks for the updates LH. sounds like it is a winner.
I can understand the necessity of a pad mount, we get a lot of leaves built up around here due to wind.
Also it would keep the unit above the coldest parts of the outside of the house.
Good to read your results.
We have a small 800/1200 watt radiator that gets used rarely, but as you point out it really only heats someone who is sitting in front of it.
Cheers
Pete
Title: Re: Mini Split
Post by: lighthunter on February 05, 2022, 07:49:45 pm
Very good point Pete! Air temperature does change with height above ground and if outside unit is mounted on sunny side of home it could benefit from being mounted up a distance above ground for heating and cooling.
 Using the AHRI numbers for the model i have, i made a graph of btu vs outdoor air temperature. Green is heat pump performance, the red is an equivalent watt resistance heater. Hspf 9.5 in this case refers to 9.5 btu/watt in region 4. One bugger about the AHRI numbers is they do not include energy used for defrost cycles which can be significant not to mention the unit is not heating during defrost cycle. Even still if using it around water freeze temps and above, it really works well.
Note AHRI label posted earlier is for a very similar unit that cost $300usd more than this one which is posted below.
Title: Re: Mini Split
Post by: Pete on February 06, 2022, 03:07:02 pm
HI LH, I haven't seen BTU's quoted for a long time. As we only use metric stuff in Oz, BTU's went out a long time ago.
I wonder how British Thermal Units differ from any other countries thermal units. But then they must have got in first with naming rights.
Pete
Title: Re: Mini Split
Post by: lighthunter on February 06, 2022, 05:15:35 pm
Hi Pete! Ha! I cant even guess which one you guys  use😁.
Maybe. Calories? Or Joules?

Looking through this conversion app ive had for years and i see someone was bored with a sense of humor.😂


Title: Re: Mini Split
Post by: lighthunter on February 06, 2022, 05:20:14 pm
Energy
Title: Re: Mini Split
Post by: Pete on February 07, 2022, 02:52:46 pm
Yep looks like someone had far too much time on their hands. A bit like those you tubers who have to explain the bleeding obvious to everyone who looks at their videos.
As far as heat goes , I see calories mentioned for food energy
and most of the time Kilojoules is the common measurement used here
Pete
Title: Re: Mini Split
Post by: lighthunter on February 12, 2022, 09:04:53 am
Hey guys, were in the middle of another cold snap again. It has cycled many times this winter to the negative digits for a week or so then 2 to 3 days of mild temps which has allowed the minisplit heat pump feature very useful. Last night i fell asleep without turning it off and i woke at midnight and saw outdoor temp at -4F (-20C). To my surprise it was heating quite nicely, not a ton of heat like above freezing temps but obviously better than a plain electric heater.
I know the sales info said it could heat down to -13F but really didnt belive it would be effective. So i got to digging a bit more and it turns out they are indeed not all the same design. I kept seeing the term "hyperheat compressor" while i figured there was something to it, no company that i had read about went into detail and it seemed like more of a marketing gimick. Yet a few mfgs would list able to heat to -13 while others didnt mention it. 

It turns out the "hyperheat" compressor feature is not a standard compressor, it has 3 refrigerant pipes instead of two which is called. "enhanced vapour injection".

The unique compressor has two input ports, the traditional suction port and a mid-pressure port. An additional heat exchanger provides mid pressure vapor to this port while the compressor compresses both intakes to the high temp discharge port.

 The result is high pressure/temperature lift capability of a two-stage compressor without needing two compressors.

This feature perhaps isnt important for someone who doesnt need to heat in below freezing temperatures but i have no idea at what temps the control starts using this feature or maybe its continuous. This is a much more complex refrigerant circuit than the yesteryear car air conditioner where you had a pump, two radiator heat exchangers an orfice and a phase change gas of some type. I know you can buy these 12k munisplits anywhere from $523 to $2500.  I think it is doubtful you would get this type of compressor at the low end especially when they dont mention it. On the other end, i cant comment but the math dollar/btu doesnt seem worth it but then longevity/quality/ actual performance etc is something ive no information on.

Boring stuff to many im sure, i just thought it kinda interesting. Seems a shame this info isnt commonly included in sales literature but then many may not care.

I found the refrigeration piping diagram for this unit and it doesnt look like it has the hyperheat feature so i dont know how they get it to perform that well. Maybe by winding the compressor up to a really high speed r410A can get hot at 400+ psi. Whatever the case it seems to work well. Maybe thats the reason for the high price of the mitsubishi models, HA!

 Have a great day!

Title: Re: Mini Split
Post by: Pete on February 12, 2022, 03:00:00 pm
Well is does get pretty cool at your place. Amazing that the heatpump was still working well down to minus20 c.
Does it run more and subsequently use more power when it is really cold?
Just wondering what sort of KWH per day it is using.
Pete
Title: Re: Mini Split
Post by: lighthunter on February 12, 2022, 07:47:16 pm
Hi Pete! Its amp draw is usually 5.1-5.3A at 240v during heating (1224-1272w) during defrost its less. So the thermostat setting and heat load in the room will throttle it back from there. It never really shuts off unless you lower tstat setting. When it catches up to the setpoint (61F) is as low as it goes then the usage can drop back under 2 amps. Ive not watched it for the minimum but one nice thing is it runs much more efficiently once it reaches setpoint because the outside radiator isnt maxed out and wont frost as easily especially above frrezing ambient temps. I will get some numbers next warm spell.
Title: Re: Mini Split
Post by: Pete on February 12, 2022, 09:25:28 pm
Thanks LH, it is good to know how much and how often they run. Still looking at them but so far I have a few years of firewood stored.
Enjoy the winter
Pete
Title: Re: Mini Split
Post by: lighthunter on February 20, 2022, 02:24:33 pm
Hi Pete! The outside temp at 1 pm today was 45°F(7.2C). The mini S heat pump was caught up at noon to the 61° minimum setpoint. The unit throttled back to 1.97A at 240V. Im thinking it can reduce further as OAT (out air temp) goes up. It will be interesting to see how low minimum is before it just shuts off.


Its crazy how much ice has built up around it. Literally a frozen pond on a grade, easy to fall on the caboose if not careful. When warmer weather arrives, i will remount it at the same height as refrigerant pipe exit. I dont think you dare mount it above the height of the refrigerant pipes so oil can drain back to compressor in outdoor unit.
Next heating season i will hopefully be ready to run it and two more like it with a turbine and a few more panels. I want splitting wood to be an option not a must during retirement. This winter the wood boiler has been a continuous burn since october. At least ive not had to light a fire.😁
Title: Re: Mini Split
Post by: Pete on February 20, 2022, 03:13:25 pm
It sure gets cold there in winter. Our house is very tiny, so we light the wood heater in winter and usually let it go out in the afternoon. Once the house gets to 21 or 22 degrees C ( 70 to 71F) we open the door for a while, to cool the house down.
Neither of us sleep well in a heated house, so we let the heater go out in the afternoon.
Your place is way colder than here.
What are the Summer temps like there?
Here we get a few days above 25C but most days are around 20C and below. This morning it is 4C outside and sunny. I think we are heading for about 15C today which is perfect for us.
Have fun
Pete
Title: Re: Mini Split
Post by: lighthunter on February 23, 2022, 02:17:19 am
Hi Pete, yeah -7F (-21C) here at the moment. I shut the heat pump off this afternoon. Some ice bridging up at bottom of coils from snow as we just had a storm. I will have to make a cover to prevent that next year.

 When i was brooming snow off solar panels the sun was about half (over 5 amps on 8 amp panels) between the current and dark surface it melted and evaporated any remaining snow in an hour. I didnt look at OAT but it wasnt near melting anywhere else. So solar panels do clear themselves of snow especially if at correct winter angle.

Regarding open door to cool off house, HA! I have a buddy that does that often here even! Its a good problem to have😁.
It does warm here in summer, rarely over 100F(38C)usually hot is 90-95, my younger years we never worried about AC but now people see it as a requirement. Where i work is not air conditioned in the shop but offices are. Humidity here is quite high normally which counts for a lot.

I put together another graph comparing output of minisplits in heating mode and its real surprising how much variance there is. Cooling mode you are only working with a 20 degree differential so its not so much work but depending on where you live heating can require 70F (45C) of lift. The performance data is hard to obtain and for some reason doesnt match AHRI tests, very puzzling. But here it is. These are just 4 arbitrary units i looked at not necessarily the best or all inclusive of whats available. The top performer, 9Kbtu Fujitsu Halcyon XLT (hspf 14.2) next 12kbtuThermocore, (12) then a 9kbtu mrcool (12) and at the bottom, the pioneer (9.5) i have. The straight line is a 1350w resistive element which is supposed to represent consumption of each but only true of the pioneer maximum. Prices are $1800, $1100, 760, 750. The top 3 are all labled as "hyperheat" though the technology used is unlikely the same. I have not personally tested these so i cant speak for accuracy but most of the data came from mfr data sheets. Its also interesting the electricity used is not similar. For instance, the bottom one claims to be around 1250w full heat, i have verified. The Thermocore is using 2kw around the 0 degree mark. It goes down above and below that OAT. It kinda makes the graph misleading. So choosing one of these, price vs performance can be tricky as they are very dynamic animals but worth the trouble, like solar panels😁



Title: Re: Mini Split
Post by: lighthunter on March 08, 2022, 03:49:17 am
Recent storm proves ground pad is not what you want for harsh winter conditions. Off the ground and a doghouse of sorts would help with freezing rain. Ive had to pour hot water to melt ice about 5 times this winter. Not a tremendous amount of care but it could be avoided with install changes.

I plan to use a large plastic container to catch condensate next season. That way i can move it away from garage foundation and break ice from tub once a month.

Lowest current draw ive seen is around 3 amps (720w) of minimum modulation but then maybe the heatload wont allow lower as yet. Ive a feeling this 12k btu can only modulate from 720w to 1250w. Every machine is different but i personally think this one would be better off for efficiency wide open and then off for heat mode at least. Because of this issue i have decided on 9k unit for the next one so it can modulate lower down to match load, i understand this is especially important when used for cooling. That is if you want to realize stated efficiencys. It appears like a small modification to the indoor temp sensor could allow external manual control of power usage anywhere in modulation range.
Title: Re: Mini Split
Post by: lighthunter on March 13, 2022, 06:32:38 pm
Hi all!

Very mild heating today. Outside temp only 10°F below the 61°F setpoint in garage.
Thought id check the minimum modulation current on the mini split. Room temp was extremely close to set point but it was not off, it was throwing a healthy supply of luke warm air. Supply volts 119.2-120.8- 1 volt for line loss. 239v @ 1.75A. = 418w. Ive no idea if it can go lower but ive never seen it this low.

This is a 12000btu unit. They make 9000 btu units that would be capable of modulating lower than this one, guessing they could hit 200w or less. Very nice. Two of the 3 arrays were off most of today. Kinda sad but good problem to have i guess.

Friday evening i noticed programmable relay control rebooting by itself every 20 sec or so and relays of all kinds switching back and forth. I killed power and fixed it this morning. Turned out to be a 48-12 buck converter that was unable to put out 250ma while rating is 10A. I had a spare, swapped it in and running in a few minutes. The culprit i suppose is this P75NF75 FET, 75V 80A driven by a UC3845A PWM controller. Will order a few tomorrow. Its been running several years so i cant complain. Nice thing is the control switched to grid without anyone even knowing there was an issue. (My sweetheart is very easy to get along with as long as her cell phone and the electricity are working properly...whew :P
Title: Re: Mini Split
Post by: noneyabussiness on March 13, 2022, 08:07:25 pm
with the uc3845 IC , check the current sense resistor... had some corrosion on one once and it did a very similar thing .. worked fine for years then suddenly wouldn't supply even the tiniest current ( but voltage regulation unloaded was fine).. cleaned the corrosion off and sealed the board ... been fine since...
Title: Re: Mini Split
Post by: lighthunter on March 14, 2022, 07:18:35 pm
Thanks, that makes sense, no corrosion to speak of but looks like board was never cleaned after assembly. Certainly could be some leakage. Will clean and test tomorrow, then let you know how it turned out.

We were talkin about meters today at work. I grabbed a Fluke 114 off the bench and tried to check internals of a SICK safety relay with it. It didnt even have a diode check function :o. Ok rant end.
When troubleshooting this buck converter, i used a uniT210e dc clamp meter, clamped the yellow wire and it read 250MA then i used probes to measure 10.xx volts on same wire. It sure made troubleshooting easy. I love fluke meters, it just frustrates me when they omit necessary stuff. I have a 189 in my tool bag but i think its gonna get replaced by a uniT. Not because of price but because it does it all, simple and lighter.
Title: Re: Mini Split
Post by: solarnewbee on April 08, 2022, 04:12:04 am
Hi LH, I have installed dozens and dozens of the Pioneer brand mini split. HVAC was my primary business before Covid  Samsung and Mitsubishi when people wanted a familiar brand name. There are other brands with different names but the cases are the same they just slap on the name the customer wants when they order from china. I never had a call back for Pioneer labeled brand or any other brand from china but Samsung and Mitsubishi had many call backs for dead compressor, blown inverter board or bad indoor co from board. As a matter of fact I have 3 pioneer in boxes waiting to be installed when remodeling is done. Summer is almost here in the Philippines so projects need to be rounded out so we don’t run those amp hungry window units.

Adios
Title: Re: Mini Split
Post by: lighthunter on April 09, 2022, 08:05:47 am
Thats interesting SN, thanks for your post! As ive looked at the high end units, ive noticed more comments about failures. Wondering if very high hspf values could equal very thin radiators, not to mention pushing the limits of 410 pressures. Ive cautioned people on going too high performance or too low and choosing a mature product. Your experience is valuable. Yeah, ive 0 complaints on the pioneer, the indoor fan is even quieter than most ive seen.  I turned it on max the other day for a friend to check noise at outdoor unit. It was about 55db running at 0°C OAT. Also discharge air temp in photo. i doubt thats accurate since meter is in airflow but after only a few seconds, my hand felt frostbite for 5 min after so it was cold😨 (farenheit in photo).  And a photo of current draw while still producing heat. (Probably minimum) this is 12k unit.
We really like it.