Adjustiing/mod'ing digital thermostat on LG window air conditioner
Dan
The unit has a digital thermostat, which on its lowest setting
displays 60 degrees. However, it is not possible even on this lowest
setting to get the machine to put out cold air below about 69 degrees.
Note I do not mean the machine does not have the capacity to cool the
space (a bedroom of about 175 sq') below 69 degrees, but rather, the
thermostat shuts the compressor off at 69, even when it is set at "60".
I tried moving the electronic temp sensor (thermistor?) from the front
of the evaporator to a position out in the room, thinking this spot
would be warmer & therefore the unit would run longer. This dropped the
room temp about 2 degrees further, to around 67. My wife & I would
prefer about 65, if not lower, for sleeping. Again, this is not a case
of the unit lacking the cooling capacity to reach lower temps, the
thermostat just won't turn the compressor on any lower. So I am
wondering if there is generally a way of adjusting these digital
thermostats (I had a similar issue with a unit having an old style
mechanical thermostat, the type which can be adjusted be varying the
spring tension on the thermostat, tweaking this I was able to get the
unit to attain a lower temp). Perhaps there's a trimmer pot on this
electronic thermostat which can be tweaked? As a second option, maybe I
could connect a wall mount thermostat of the type used on a central air
unit, which would be more accurate. Does anyone know if this can be
done? I'm guessing the thermostat on a window unit directly turns the
compressor on and off, and therefore has the current switching capacity
required for this, while a wall mount type for a central unit probably
signals a central control board on the furnace/ac, which has a relay
that does the actual switching. Is this the case? I could probably set
up a relay, still we're beginning to get to the point of a lot a
screwing around by that time. Anyone have any ideas?
TIA
Dan
i.hat...@comcast.net
> As a second option, maybe I
> could connect a wall mount thermostat of the type used on a central air
> unit, which would be more accurate. Does anyone know if this can be
> done? I'm guessing the thermostat on a window unit directly turns the
> compressor on and off, and therefore has the current switching capacity
> required for this, while a wall mount type for a central unit probably
> signals a central control board on the furnace/ac, which has a relay
> that does the actual switching. Is this the case? I could probably set
> up a relay, still we're beginning to get to the point of a lot a
> screwing around by that time. Anyone have any ideas?
I also have an LG air conditioner with digital controls and would like
to do the same. Mine is a rather large and expensive unit, so I am
reluctant to butcher it or risk damaging it. I am curious as to what
type of component the temperature sensor is.
If the temperature sensor for the digital controls is a thermistor
then it would be easy to make a circuit involving a central AC
thermostat (you would need a stat that uses a relay output instead of a
triac) and a couple of resistors to emulate the sensor indicating a
high temperature or a low temperature to manually control the
compressor.
If the sensor is some sort of temperature sensitive transistor, it
would be a bit tougher to design a similar circuit. If it's a
thermocouple, it is even worse.
If you were to do something like this you would have to beware of
evaporator coil freeze up, especially at the temperature you wish to
run the unit at, since the temperature sensor is no longer in front of
the coil. Evaporator coil freezup can easily ruin the compressor.
Eric
Dan
>
> I also have an LG air conditioner with digital controls and would like
> to do the same. Mine is a rather large and expensive unit, so I am
> reluctant to butcher it or risk damaging it. I am curious as to what
> type of component the temperature sensor is.
>
> If the temperature sensor for the digital controls is a thermistor
> then it would be easy to make a circuit involving a central AC
> thermostat (you would need a stat that uses a relay output instead of a
> triac) and a couple of resistors to emulate the sensor indicating a
> high temperature or a low temperature to manually control the
> compressor.
>
> If the sensor is some sort of temperature sensitive transistor, it
> would be a bit tougher to design a similar circuit. If it's a
> thermocouple, it is even worse.
>
> If you were to do something like this you would have to beware of
> evaporator coil freeze up, especially at the temperature you wish to
> run the unit at, since the temperature sensor is no longer in front of
> the coil. Evaporator coil freezup can easily ruin the compressor.
>
> Eric
>
Eric-Thanks for the reply. I agree about the freeze up potential, have
to keep an eye on it at least initially. I have forced it to run longer
by holding the temp sensor between my fingers for a period of time, so
far minimal frosting on the evaporator. On the other hand, it's not
that humid here at the moment. Another option might be to slightly heat
the sensor with something like a low wattage light bulb placed at a
distance, though again this is kind of a PITA, especially in a bedroom
:-/ This particular unit was fairly cheap, about $160.
Dan
Ken Weitzel
Hi Dan...
I suspect you and your wife might like a 5 or 10 watt
ceramic resistor with a half amp or so at 12 volts better than
a light bulb :)
However, I respectfully suggest that perhaps you and Eric are
asking more of a home cooling unit than it was designed for and
intended to do. Think perhaps you guys liking to sleep at
65 degrees F are in a real minority. Not to mention the
cost on your hydro bill :)
My car has auto climate control. Switched to "US" mode, the
auto temp will drop degree by degree, until it suddenly jumps
to 50F. I'd assumed that meant that it would run virtually
forever, or until it reached 50 if ever. Not so, just tried
it. Something else shuts it down long before it gets that
cold.
Just my 2 cents, FWIW
Take care.
Ken
Mike Berger
condensation or restricted airflow?
Dan
> Are you sure it's not shutting down for another reason, like
> condensation or restricted airflow?
>
Yes, it's the thermostat. After I pulled the sensor from the front of
the evaporator, holding it in my hand momentarily warms it enough to get
the compressor to kick in.
Dan
Dan
> Hi Dan...
>
> I suspect you and your wife might like a 5 or 10 watt
> ceramic resistor with a half amp or so at 12 volts better than
> a light bulb :)
A power resistor is a great idea! Why didn't I think of that!?!
>
> However, I respectfully suggest that perhaps you and Eric are
> asking more of a home cooling unit than it was designed for and
> intended to do. Think perhaps you guys liking to sleep at
> 65 degrees F are in a real minority. Not to mention the
> cost on your hydro bill :)
Hydro bill shmydro bill ;-) I don't doubt you're correct about our
preference for low temps. We open the bedroom windows in February!
Honestly though, I have met others who also like sleeping in the cold.
I have been able to attain the desired temps with other 8kbtu window
units in another bedroom in a climate with a much higher heat load
applied; hotter weather, higher humidity, less insulation, less shade,
etc. I think the unit is capable of what I want, the thermostat just
doesn't think so ;-)
>
> My car has auto climate control. Switched to "US" mode, the
> auto temp will drop degree by degree, until it suddenly jumps
> to 50F. I'd assumed that meant that it would run virtually
> forever, or until it reached 50 if ever. Not so, just tried
> it. Something else shuts it down long before it gets that
> cold.
Probably the same thing, the thermostat is killing the car's AC
compressor clutch before it gets to the indicated temp. I didn't really
expect the "degrees" indicated by the unit's digital readout to be all
that accurate, but if they have a scale going down to 60, I really do
think the damn thing ought to be capable of more than 69 when used in a
space of the size etc. indicated by the btu output.
J. Clarke
If I may venture a stupid question, are you sure that the thing isn't simply
defective?
> TIA
>
> Dan
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
tra...@optonline.net
Or even if that's the way that particular unit was made, since the OP
just bought it, why not just take it back and get one from another
manufacturer? I would think someone must make one that goes below 68.
As a kludge, it sounds like the small power resistor secured to the
temp sensor and controlled by a thermostat located elsewhere would
work. You'd have to do the math, make sure the thermostat could
handle the current or use a relay, use low voltage (12V) for safety,
etc.
Rheilly Phoull
I'd be thinking of a pot in parallel or series with the thermistor.
Assuming you dont want to open up the controller to find adjustments.
--
Regards ......... Rheilly Phoull
Dan
> J. Clarke wrote:
>> If I may venture a stupid question, are you sure that the thing isn't simply
>> defective?
>
>
> Or even if that's the way that particular unit was made, since the OP
> just bought it, why not just take it back and get one from another
> manufacturer? I would think someone must make one that goes below 68.
>
> As a kludge, it sounds like the small power resistor secured to the
> temp sensor and controlled by a thermostat located elsewhere would
> work. You'd have to do the math, make sure the thermostat could
> handle the current or use a relay, use low voltage (12V) for safety,
> etc.
>
Not a stupid question at all. I'm planning to at least swap out this
one today, I just wanted to get some input in case the 2nd example
performs the same way. The problem is this wasn't a typical double hung
installation, the window is a large (tall but narrow) panel which swings
out vertically, I had to remove the window (large, heavy, 2nd floor, no
outside access) & make & install a plywood panel of the right dimensions
to go above the unit. In other words, taking the damn thing out &
putting it back in is a major PITA. I could try another brand, but I'm
not guaranteed it won't behave the same way (it's been at least 7 years
since I had to deal with a window AC, I thought perhaps this was "just
they way they are now", that maybe they won't go any lower for energy
concerns or something) and if its size is different it may require
modifying what was a fairly troublesome installation, especially if it's
shorter & I have to cut/paint another longer plywood panel. Too bad the
mother couldn't just WORK the way I wanted out of the box, (really, I
don't think expected lower than 69 is too much to ask) but alas things
don't seem to go that way for me too often... ;-)
Thanks also for the suggestions on a work around.
Dan
Andy Cuffe
>I just bought an LG 8000 BTU window air conditioner, model LWHD8000RY6.
> The unit has a digital thermostat, which on its lowest setting
>displays 60 degrees. However, it is not possible even on this lowest
>setting to get the machine to put out cold air below about 69 degrees.
I suspect they are limiting it to 69 in order to save energy (probably
an EPA regulation). The simplest solution would be to buy an A/C with
an analog thermostat. It's probably possible to modify the digital
thermostat, but you'd have to figure out how by tracking the circuit
and looking for data sheets for any ICs. It's probably custom to that
A/C and it will be impossible to find a schematic. It might be as
simple as a jumper to switch it to non-EPA mode, or you might have to
modify the temperature sensor circuit. If you modify the temperature
sensor, you'd have to live with an inaccurate temp display (eg. it
still shuts off when it thinks it's 69, but it's actually 65).
Andy Cuffe
Dan
>
> I'd be thinking of a pot in parallel or series with the thermistor.
> Assuming you dont want to open up the controller to find adjustments.
>
I thought of that as well, easy enough to check but at the moment I'm
not sure it IS a thermistor...
Dan
GregS
Round bulb in center of evaporator? I'm just listening. I am going to try
and set mine to below the mark tonight. Mine just has a 9.7 rating.??
greg
larry
my 5K gold star window air:
bg5200er
limited schem on top of black plastic control box)
sensor - thermistor(non polar) in black epoxy glob:
oF ohms
212 = 1.2k
finger(98) = 6.6k
warm room(82) = 7.8k
32 = 26k
negative factor (hotter = lower resistance)
draw a linear chart, see if my numbers are on the line
use ohms law
have fun
-larry / dallas
BTW- if anyone trashes one of these, I would like to buy
your circuit board and keyboard/display. I have a GE I want
to teach new tricks ;-)
Dan
> my 5K gold star window air:
> bg5200er
> limited schem on top of black plastic control box)
> sensor - thermistor(non polar) in black epoxy glob:
> oF ohms
> 212 = 1.2k
> finger(98) = 6.6k
> warm room(82) = 7.8k
> 32 = 26k
>
> negative factor (hotter = lower resistance)
>
> draw a linear chart, see if my numbers are on the line
>
> use ohms law
>
> have fun
>
> -larry / dallas
>
> BTW- if anyone trashes one of these, I would like to buy your circuit
> board and keyboard/display. I have a GE I want to teach new tricks ;-)
>
Thanks Larry, very interesting info. If the sensor in mine also turns
out to be a thermistor (a likelihood) it really simplifies tweaking. In
the case of your figures, you could fool the thermostat into thinking it
was 98 when it was actually 82 by shunting the thermistor with 42,900
ohms. Since the range of actual thermistor values over real room
temperatures would be fairly narrow, something along these lines would
probably be safe (only down side is the temp readout would be wrong, but
since it is anyway (says 60 when it's 69) no loss there). Also very
easy/cheap to implement.
Dan
Ken Weitzel
Dan wrote:
Hi Dan...
With all this great info, seems you can't go wrong! :)
Another suggestion might be to consider using perhaps a 100k
variable rather than a fixed resistor.
A bit of tweaking might let you make the readout "wrong" by
10 degrees F, so that for instance you could more understandably
have 65 degrees read 75, etc.
Take care.
Ken
Dan
>> Thanks Larry, very interesting info. If the sensor in mine also turns
>> out to be a thermistor (a likelihood) it really simplifies tweaking.
>> In the case of your figures, you could fool the thermostat into
>> thinking it was 98 when it was actually 82 by shunting the thermistor
>> with 42,900 ohms. Since the range of actual thermistor values over
>> real room temperatures would be fairly narrow, something along these
>> lines would probably be safe (only down side is the temp readout would
>> be wrong, but since it is anyway (says 60 when it's 69) no loss
>> there). Also very easy/cheap to implement.
>>
>> Dan
>
> Hi Dan...
>
> With all this great info, seems you can't go wrong! :)
>
> Another suggestion might be to consider using perhaps a 100k
> variable rather than a fixed resistor.
>
> A bit of tweaking might let you make the readout "wrong" by
> 10 degrees F, so that for instance you could more understandably
> have 65 degrees read 75, etc.
>
> Take care.
>
> Ken
>
I agree a pot is the way to go, after calculating a ballpark figure.
Thanks!
Dan
Mike Berger
forever to cool down a space. For your purposes you would
probably be happier with an inefficient model, and you might
need to size it up.
ze...@comcast.net
I didn't note the model # but I just bought an 8000 BTU at The Home
Depot.
I tested it and it goes to 60 deg. I put a thermometer near the sensor.
gs
Dan
> Dan wrote:
> I didn't note the model # but I just bought an 8000 BTU at The Home
> Depot.
> I tested it and it goes to 60 deg. I put a thermometer near the sensor.
>
> gs
>
Thanks for the reply. I checked the temperature across the room on a
bedside table. Since the sensor is on the evaporator, it may very well
get to 60 right there, unfortunately it's a little cramped for living
space under the filter ;-) With mine set at 60, the lowest I could get
it in the room was 69, this on a day that wasn't more than about 74. I
attached a 100k pot in series with a 47k resistor across the thermistor,
adjusted to about 75k total (have to remove & measure to be sure) I was
able to get the room down to 61, with an outside temp of around 75. I
don't plan to keep the room this cool, but it does show the machine has
the capacity to lower the temp sufficiently if the thermostat tells it
to. Very easy mod, in case anyone else has a similar issue with a room AC.
Thanks again all who replied.
Dan
ian field
"Mike Berger" <ber...@shout.net> wrote in message
news:e642p2$j2p$1...@roundup.shout.net...
Energy efficient my arse!!! - they chug away drawing 9kW for bloody hours to
drop the temperature 1C. Its not about energy efficiency, its about non-CFC
ozone friendly refrigerant that's next to useless!!
Connie
How do u do this. Mine does the exact same thing and it used to go lower than
69.
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Tim R
What is the delta T? (what is the temperature of the air entering the air conditioner and what is the temperature of the air being supplied to the room)
Refrigerant charges are weighed in (if the maker is careful) or just estimated if not. Either way it is possible to customize them for the actual use scenario based on superheat and subcooling measurements.
Twai
My lg lw2510window AC compressor don't shut off.
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Ryan
I am having the same issue with a brand new wall unit. At least my room temp
goes down to about 65/66 when set at 60. But this is very annoying that these
are all calibrated wrong! Do they do this on purpose to appease the global
warming cults or something?
RION
Well, here it is 2018, and I am having a similar problem with an 8,000 BTU
window ac. I guess I should feel luck that mine does go down to 65.7 F. The
problem here is that I bought this to cool a wine cellar. The ac unit is in a
fake window between two parts of my basement. The wine cellar part is well
insulated, but you can't get 60 F (the temperature I really desire) if the
calibration on the thermistor is wrong. I am getting ready to use a fixed
resistor along with a pot, and hope I get lucky.
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