Lowest low ambient operating temp for 1 ton mini-split.

[Shmavis]

Trying to do my due diligence researching mini-splits.

Hoping for some advice here. I’m drowning in spec sheets.

1 ton will be more than sufficient for my modest setup. So I’m interested in 1 ton models that can still operate in winter temps down to 0 degrees F. Most of the 1 tons that I’ve been looking at have low ambient capability already installed. But this only amounts to 14 degrees F. I found a Fujitsu that will run at 0 degrees F, but it’s 2 ton.

While my primary concern had been price points and ease of installation, that’s quickly shifted to operating temperature ranges.

Are there 1 ton minis that can operate at 0 degrees F, which I just haven't run across yet?

Greatly appreciate any advice, insights, recommendations.

Thanks!

 

[Ez Rider]

Trying to do my due diligence researching mini-splits.

Hoping for some advice here. I’m drowning in spec sheets.

1 ton will be more than sufficient for my modest setup. So I’m interested in 1 ton models that can still operate in winter temps down to 0 degrees F. Most of the 1 tons that I’ve been looking at have low ambient capability already installed. But this only amounts to 14 degrees F. I found a Fujitsu that will run at 0 degrees F, but it’s 2 ton.

While my primary concern had been price points and ease of installation, that’s quickly shifted to operating temperature ranges.

Are there 1 ton minis that can operate at 0 degrees F, which I just haven't run across yet?

Greatly appreciate any advice, insights, recommendations.

Thanks!

http://http://www.globalindustrial.com/p/hvac/controls/pressure-switches/p70aa-118c-condenser-fan-cycling-controls-for-non-corrosive-refrigerants?infoParam.campaignId=T9F&gclid=CNnB__-Zw8sCFQJsfgodYyYClA

Use one of these to shut off the condenser fan in low ambient conditions.

 

[eebbnflow]

There's also a unit that I inquired about a few years ago but never went through it . it was the Mitsubishi p series it can handle -50c temp (apparently) . I was really interested for that feature alone .

 

[Shmavis]

http://http://www.globalindustrial.com/p/hvac/controls/pressure-switches/p70aa-118c-condenser-fan-cycling-controls-for-non-corrosive-refrigerants?infoParam.campaignId=T9F&gclid=CNnB__-Zw8sCFQJsfgodYyYClA

Use one of these to shut off the condenser fan in low ambient conditions.

Thanks, I appreciate it.

Please excuse my ignorance, as minis are new to me.

If I understand the function of this equipment correctly, it will act as a safeguard for the condenser; protecting the mini during extremely cold weather. Thereby stopping the cooling of the room. So if during a cold snap lasting a few days, the condenser would effectively be shutdown and I would be without control over the room — lots of heat with no means of fighting it. Would this be correct, or am I missing something?

There's also a unit that I inquired about a few years ago but never went through it . it was the Mitsubishi p series it can handle -50c temp (apparently) . I was really interested for that feature alone .

This looked promising. But the P-Series is discontinued. If not the series itself, then the model that I would be interested in.

But that’s pretty cool that I could’ve been protected up to -40. (!)

 

[sourpuss]

Save some money and draw fresh cold air intakes on temp sensors.

 

[Ez Rider]

Thanks, I appreciate it.

Please excuse my ignorance, as minis are new to me.

If I understand the function of this equipment correctly, it will act as a safeguard for the condenser; protecting the mini during extremely cold weather. Thereby stopping the cooling of the room. So if during a cold snap lasting a few days, the condenser would effectively be shutdown and I would be without control over the room — lots of heat with no means of fighting it. Would this be correct, or am I missing something?

When the head pressure of the compressor drops too low or goes too high, the unit ceases to cool. In an extreme low ambient condition, the condenser coils get too cold, and the head pressure drops below the point where the unit will cool. By shutting off the outdoor fan, you let quite a bit more heat build up in the condenser. The head pressure rises, and voila, the unit is cooling again. When the head pressure starts to get too high, the fan will kick back in to lower it. All it's doing is manipulating the outdoor fan to maintain the proper temperature/pressure relationship in the system. I installed a bunch of heatpumps with this setup many years ago. It works very well. You need the pressure switch and a relay for the outdoor fan. Any competent supply house should be able to set you up with the exact parts for your specific unit, and help you with the setpoints for the pressure switch.

Save some money and draw fresh cold air intakes on temp sensors.

 

[queequeg152]

do NOT buy that controller for a minisplit.

that is for a conventional single stage on/off condenser fan motor, not the variable speed fans you find inside most minisplits.

that controller requires a flared connection be added to your condensing unit. it could possibly be connected to your service valves, but this would probably require removing any Schroeder valve and keeping the service valves open all of the time. not a good idea.

i dont know exactly what threads are on minisplits, but i believe thery are NOT the standard 1/4" flare thats on conventional systems.
you could probably use a piercing saddle with a valve? but i would not... just asking for problems.

minisplits manage head pressure via a simple theromwell or sensor clipped somewhere on the return line, usually on the condensor coil itself. the controller modulates the condensor fans speed based on this temp. some of these things might possibly have a pressure sensor on the refrigerant line, but ive never seen that on one of these minisplits.

beign a "smart" fan, it also likely has a feedback loop constantly sending rpm data from the fan back to the controller. its likely that if you cut off the fan contacts with that mechanical controller, you will trigger an error state as the controller believes the fan is malfunctioning.

the best person to discuss accessories with will be the manufacturer. its possible there may be an optioned model or model they can point you to thats setup with expanded accumulator on the suction or a different expansion valve, crank case heaters, different fans etc that would best suit you.

i dont know what mitsubishi customer service is like, but im guessing a potential customer would have littler problem speaking with a regional sales rep or engineer about this issue. its a very common issue with commercial split unit freezers that run year round inside a heated space.
sealed non ventilated equipment rooms sometimes also need a minisplit, even in the hottest of months. its just not an uncommon request at all.

 

[Ez Rider]

do NOT buy that controller for a minisplit.

that is for a conventional single stage on/off condenser fan motor, not the variable speed fans you find inside most minisplits.

that controller requires a flared connection be added to your condensing unit. it could possibly be connected to your service valves, but this would probably require removing any Schroeder valve and keeping the service valves open all of the time. not a good idea.

i dont know exactly what threads are on minisplits, but i believe thery are NOT the standard 1/4" flare thats on conventional systems.
you could probably use a piercing saddle with a valve? but i would not... just asking for problems.

minisplits manage head pressure via a simple theromwell or sensor clipped somewhere on the return line, usually on the condensor coil itself. the controller modulates the condensor fans speed based on this temp. some of these things might possibly have a pressure sensor on the refrigerant line, but ive never seen that on one of these minisplits.

beign a "smart" fan, it also likely has a feedback loop constantly sending rpm data from the fan back to the controller. its likely that if you cut off the fan contacts with that mechanical controller, you will trigger an error state as the controller believes the fan is malfunctioning.

the best person to discuss accessories with will be the manufacturer. its possible there may be an optioned model or model they can point you to thats setup with expanded accumulator on the suction or a different expansion valve, crank case heaters, different fans etc that would best suit you.

i dont know what mitsubishi customer service is like, but im guessing a potential customer would have littler problem speaking with a regional sales rep or engineer about this issue. its a very common issue with commercial split unit freezers that run year round inside a heated space.
sealed non ventilated equipment rooms sometimes also need a minisplit, even in the hottest of months. its just not an uncommon request at all.

Nobody suggested he use that specific control. It was an EXAMPLE. Any head pressure kit mitsu makes will work EXACTLY THE SAME WAY. I'm pretty sure I said to speak to mitsu or a supply house about specific controls for his unit. What is a "schroeder" valve anyway? I didn't know Ricky was in the ac business

 

[queequeg152]

Nobody suggested he use that specific control. It was an EXAMPLE. Any head pressure kit mitsu makes will work EXACTLY THE SAME WAY. I'm pretty sure I said to speak to mitsu or a supply house about specific controls for his unit. What is a "schroeder" valve anyway? I didn't know Ricky was in the ac business

eh, my apologies if i misunderstood.

i just read the post "use one of these to shut off the fan", and assumed you were reccomending that unit in particular.

like i said, these units effectivly manage head pressure via modulation of the compressor and fan motors. unless you are talking about some sort of emergency lockout type arrangement i have to disagree that minisplit parts would run the system in an identical manner to that mechanical switch.

re:
schroeder valve? did i spell it wrong? i used firefoxes autocorrect.

im talking about the depressable valves you use on biycle tires, car tires, and refrigerant service connections? these things are very common.

 

[Ez Rider]

eh, my apologies if i misunderstood.

i just read the post "use one of these to shut off the fan", and assumed you were reccomending that unit in particular.

like i said, these units effectivly manage head pressure via modulation of the compressor and fan motors. unless you are talking about some sort of emergency lockout type arrangement i have to disagree that minisplit parts would run the system in an identical manner to that mechanical switch.

re:
schroeder valve? did i spell it wrong? i used firefoxes autocorrect.

im talking about the depressable valves you use on biycle tires, car tires, and refrigerant service connections? these things are very common.

Try reading the whole thread, it's short.

Low ambient kits work by modulating, or starting and stopping the outdoor fan, based on head pressure. I fail to see the "emergency", or the point. One way or another you need a control(s) that senses head pressure, and controls the outdoor fan accordingly to maintain the proper temperature/pressure relationship in the system. It may turn out to be a digital control, but it's still going to function EXACTLY like "that mechanical switch".

You're talking about a schrader valve, I'm just having a little fun at your expense

 

[queequeg152]

Try reading the whole thread, it's short.

Low ambient kits work by modulating, or starting and stopping the outdoor fan, based on head pressure. I fail to see the "emergency", or the point. One way or another you need a control(s) that senses head pressure, and controls the outdoor fan accordingly to maintain the proper temperature/pressure relationship in the system. It may turn out to be a digital control, but it's still going to function EXACTLY like "that mechanical switch".

You're talking about a schrader valve, I'm just having a little fun at your expense

I guess we have different defination of modulation. i was taught modulation is the gradual or fine stepwise reduction of speed or gas flow or what ever, like the modulating furncaces, ECM blowers etc.

imo this is nothign like that mechanical switch. its quite a bit different, and more efficient for the most part.

the minisplit does the modulation already, out of the box. this is a VRF system afterall.
almost all of them already work vell at lowish temps down to freezing temps easily, unlike the conventional non heat pump split systems that start filling the accumulator at like 50 degrees.

where those mechanical switches or the pressure sensors come in handy is in retrofitting and existing single stage heat pump/ac unit to operate at lower temps. or better yet, you cold buy a three speed fan generic PSC motor and one of those emerson controllers that drop the fan speed in stages.
there are even vaned louver things they build around some rooftop enclosures to prevent hard winds from effecting performance in low ambient conditions.

to get these mini splits to run at even lower temps would probably require adjusting the software or control scheme in some manner, and maby by adding bypass solenoid valves or one of those valves that open up in responce to increasing head pressures.

 

[Shmavis]

Save some money and draw fresh cold air intakes on temp sensors.

I’d really like to get away from fans. As near to silent as possible is my objective. Was thinking a mini would handle that; and allow for year-round fun time...

Maybe I'll have to stick with fans. We'll see.

When the head pressure of the compressor drops too low or goes too high, the unit ceases to cool. In an extreme low ambient condition, the condenser coils get too cold, and the head pressure drops below the point where the unit will cool. By shutting off the outdoor fan, you let quite a bit more heat build up in the condenser. The head pressure rises, and voila, the unit is cooling again. When the head pressure starts to get too high, the fan will kick back in to lower it. All it's doing is manipulating the outdoor fan to maintain the proper temperature/pressure relationship in the system. I installed a bunch of heatpumps with this setup many years ago. It works very well. You need the pressure switch and a relay for the outdoor fan. Any competent supply house should be able to set you up with the exact parts for your specific unit, and help you with the setpoints for the pressure switch.

Whoa! You guys are talking way over my head...

But I really do appreciate you taking the time to explain the process.

Your explanation brings up a question for me: is the pressure regulator separate and independent of a “low ambient kit”? (It seems these two are being referenced as one and the same.) I mean to ask: if I buy a unit with “Built-in low ambient standard, down to 14 Degrees Fahrenheit (Cooling mode)”, can I further extend the operational range of such a unit with the addition of a pressure regulator? Could I, say, get operational below 0 degrees?

I ask because here’s one of the units I’m considering:

https://www.acwholesalers.com/Fried...Only/43011.ac?catId=cat1028&mainCat=&subCat=#

One of its features is “Built-in low ambient standard, down to 14 Degrees Fahrenheit (Cooling mode)” A couple other units I’m considering also state this as a feature.

If the addition of a pressure regulator will allow it to operate below 14 (and preferably even below 0), then it seems to be a no-brainer. Or does the standard low ambient kit mean that it already has a regulator and won’t accept another?

Many thanks.

 

[Ez Rider]

I guess we have different defination of modulation. i was taught modulation is the gradual or fine stepwise reduction of speed or gas flow or what ever, like the modulating furncaces, ECM blowers etc.

imo this is nothign like that mechanical switch. its quite a bit different, and more efficient for the most part.

the minisplit does the modulation already, out of the box. this is a VRF system afterall.
almost all of them already work vell at lowish temps down to freezing temps easily, unlike the conventional non heat pump split systems that start filling the accumulator at like 50 degrees.

where those mechanical switches or the pressure sensors come in handy is in retrofitting and existing single stage heat pump/ac unit to operate at lower temps. or better yet, you cold buy a three speed fan generic PSC motor and one of those emerson controllers that drop the fan speed in stages.
there are even vaned louver things they build around some rooftop enclosures to prevent hard winds from effecting performance in low ambient conditions.

to get these mini splits to run at even lower temps would probably require adjusting the software or control scheme in some manner, and maby by adding bypass solenoid valves or one of those valves that open up in responce to increasing head pressures.

I’d really like to get away from fans. As near to silent as possible is my objective. Was thinking a mini would handle that; and allow for year-round fun time...

Maybe I'll have to stick with fans. We'll see.



Whoa! You guys are talking way over my head...

But I really do appreciate you taking the time to explain the process.

Your explanation brings up a question for me: is the pressure regulator separate and independent of a “low ambient kit”? (It seems these two are being referenced as one and the same.) I mean to ask: if I buy a unit with “Built-in low ambient standard, down to 14 Degrees Fahrenheit (Cooling mode)”, can I further extend the operational range of such a unit with the addition of a pressure regulator? Could I, say, get operational below 0 degrees?

I ask because here’s one of the units I’m considering:

https://www.acwholesalers.com/Fried...Only/43011.ac?catId=cat1028&mainCat=&subCat=#

One of its features is “Built-in low ambient standard, down to 14 Degrees Fahrenheit (Cooling mode)” A couple other units I’m considering also state this as a feature.

If the addition of a pressure regulator will allow it to operate below 14 (and preferably even below 0), then it seems to be a no-brainer. Or does the standard low ambient kit mean that it already has a regulator and won’t accept another?

Many thanks.

They make a "low ambient wind baffle" for you unit. It allows operation down to 0F. It works by...are you ready for this? Restricting the airflow of the outside fan...go figure. It's like $75, and installs with a few screws. Google it.

 

[Shmavis]

They make a "low ambient wind baffle" for you unit. It allows operation down to 0F. It works by...are you ready for this? Restricting the airflow of the outside fan...go figure. It's like $75, and installs with a few screws. Google it.

By golly, that Google thingy works!

Very cool, Dude. You are The Dude.

Feel a bit silly now; but hey, in my defense, that option is not listed under accessories...

Who’d a thought?

Thanks. Thanks a lot!

 

[queequeg152]

I’d really like to get away from fans. As near to silent as possible is my objective. Was thinking a mini would handle that; and allow for year-round fun time...

Maybe I'll have to stick with fans. We'll see.



Whoa! You guys are talking way over my head...

But I really do appreciate you taking the time to explain the process.

Your explanation brings up a question for me: is the pressure regulator separate and independent of a “low ambient kit”? (It seems these two are being referenced as one and the same.) I mean to ask: if I buy a unit with “Built-in low ambient standard, down to 14 Degrees Fahrenheit (Cooling mode)”, can I further extend the operational range of such a unit with the addition of a pressure regulator? Could I, say, get operational below 0 degrees?

I ask because here’s one of the units I’m considering:

https://www.acwholesalers.com/Fried...Only/43011.ac?catId=cat1028&mainCat=&subCat=#

One of its features is “Built-in low ambient standard, down to 14 Degrees Fahrenheit (Cooling mode)” A couple other units I’m considering also state this as a feature.

If the addition of a pressure regulator will allow it to operate below 14 (and preferably even below 0), then it seems to be a no-brainer. Or does the standard low ambient kit mean that it already has a regulator and won’t accept another?

Many thanks.

email the manufacturer.

the pressure regulator you mention is actually a pressure switch. it verifies the operation of the fan condensing fan by closing or opening contacts in responce to air pressure increases.

you may also need somethign like a larger compressor heater to allow the unit to start up well in such cold temps.

you may also need a condensate defrosting heater? idk, some of these minisplits plumb the condensate drain back down through the lineset down through a drain hole in the condensing unit.

 

[biggreg]

Ive been looking into low ambient cooling as well. Its not hard to find minisplits rated down to 15,5, or even zero. minisplit warehouse has a list of grow room ac units with low ambient cooling. Amazon has the pioneer ac with free prime shipping that is rated down to zero outdoor ambient.

If you need it to be rated for colder temps, Mitsubishi and Daikin have a model that equipped with their low ambient kit and fan shroud, are the only minisplits rated to -40 that i could find.

The Bard wallmount AC designed for the telecommunications industry also has a -40 ambient rating.

 

[Shmavis]

email the manufacturer.

the pressure regulator you mention is actually a pressure switch. it verifies the operation of the fan condensing fan by closing or opening contacts in responce to air pressure increases.

you may also need somethign like a larger compressor heater to allow the unit to start up well in such cold temps.

you may also need a condensate defrosting heater? idk, some of these minisplits plumb the condensate drain back down through the lineset down through a drain hole in the condensing unit.

Thanks for the things to consider.

Ive been looking into low ambient cooling as well. Its not hard to find minisplits rated down to 15,5, or even zero. minisplit warehouse has a list of grow room ac units with low ambient cooling. Amazon has the pioneer ac with free prime shipping that is rated down to zero outdoor ambient.

If you need it to be rated for colder temps, Mitsubishi and Daikin have a model that equipped with their low ambient kit and fan shroud, are the only minisplits rated to -40 that i could find.

The Bard wallmount AC designed for the telecommunications industry also has a -40 ambient rating.

Which Pioneer (model #) through Amazon? Was pretty sure the spec sheets I looked over didn’t go that low. But I may’ve missed it. Numbers are bleeding into one another at this point.

I’ve been looking at the Pioneer through Amazon. The big appeal about that route would be one year same as cash payment option. I noticed that the unit is about eighty bucks less if bought direct from HighSeer. Seems like you can even pay there via Amazon.

Anyway, appreciate the leads.

 

[biggreg]

I was looking at the 15 SEER unit. outside operating range 0-122f . The WYE model. They also have a 22 SEER unit WYQ model.

 

[Shmavis]

I was looking at the 15 SEER unit. outside operating range 0-122f . The WYE model. They also have a 22 SEER unit WYQ model.

I’ll look into the WYE model. Maybe I’ve been too hung up on high SEER ratings.

As far as the WYQ model, I’m reading the spec sheet as stating a low of 32 F in cooling mode. The heating mode has a low ambient operating rating of 5 F. So unless I’m reading something wrong, the low ambient operating temp is only at freezing for the cooling function.

I was comparing it (WYQ) to WYS. Main difference, as far as I can tell, is that WYS is 110V whereas WYQ is 220V. Which makes the difference is amperage somewhat significant. 8.4A (960 watts) for WYS and 4.05A (885 watts) for WYQ.

Another thing to consider about the Pioneer is that there’s only a three year warranty on the compressor.

I’ve been in the electrical panel installing breakers and running wire before. I feel pretty comfortable doing that, but, I’ve never played with 220 before. So that’s another aspect for me to consider.

Regarding the Misu S series: do you see a wall mount 1 ton available? That is, at a reasonable price? As best I can tell it’s discontinued. I did find it through an online retailer, apparently a leftover, but it was over $3000. Ouch! Not sure if that price has something to do with it being discontinued or if it’s the normal price.

I’m really thinking that EZ Rider has got me where I need to be. If I can simply install a low ambient wind baffle kit around a unit that already operates at 14 F and be able to then get to 0, then this seems like a good route. Winters can be pretty brutal here. This year not so much. But the previous two had plenty of single digit days as well as plenty of -0 wind chill days. Even some negative days without windchill. But I think given the location of the outdoor unit and the baffle kit, I should be able to swing it, even if we have another crazy cold winter.

I'll have to look into Daikin and Bard, neither of which are brands I've come across yet.

Thanks.

Which way are you leaning? Are you zeroing in on one?

 

[biggreg]

My favorite is the Chilltrix CX30. Its a 2 ton minisplit chiller. Its very efficient and has a free cooling coil option that cuts the compressor off when temps are below 28 and allows the compressor to run at 50% below 38 ambient. The ceiling or wall mount airhandlers are very slim 5.1" and they use low wattage variable dc motors. I really am in love with that machine

BUT...



Our winters are super brutal (-60 some times!) and nothing works right at that temp. No manufacturer will rate that low and it cant be good for the equipment. I also just hate the thought of wasting all that heat so my solution is to place the outdoor unit in a building i want to store my soil, compost and worms in and need heated. Plan to ventilate the building controlled by a thermostat. Will use the pioneer stuff and save a ton on initial costs and the efficiency lost vs the chiller will be balanced by not having to heat my storage building. ( I'm using 6 tons total). My equipment should never be subjected to low ambient or even worse -60.