what's the problem

[botrous]

Guys , I came accros a mini-split unit . . . the problem is , sometimes the unit starts , sometimes it doesn't , in both cases the pcb receives the signal from the remote controller . . .
Anyone had a similar problem ? i mean unit starts sometime and at other time it doesn't ...
Ps: i changed the capacitors and the problem is still here

What do you think is deffective , the relay or something in the pcb

[andrewuk]

See if there is power comeing out of the relay ,then check if the relay is ativated buy the pcb circuit,that will tell you if it is the relay or the pcb.


cheers
andrew

Guys , I came accros a mini-split unit . . . the problem is , sometimes the unit starts , sometimes it doesn't , in both cases the pcb receives the signal from the remote controller . . .
Anyone had a similar problem ? i mean unit starts sometime and at other time it doesn't ...
Ps: i changed the capacitors and the problem is still here

What do you think is deffective , the relay or something in the pcb

[botrous]

Thanks Andrew , more suggestions will be welcomed

[Brian_UK]

Kind of an open ended question here....

Does the indoor unit send a start signal to outdoor unit ?

Does the outdoor unit receive the start signal ?

Does the compressor relay receive a start signal ?

Does the compressor relay respond to the start signal ?

Are all of the electrical connections correct ? Live and neutral as well as signal

Rather hard to provide a definite answer I'm afraid.

[Andy W]

Does the outdoor unit have a contactor? is the unit single phase or three phase?

[chillin out]

Are you saying the whole thing doesn`t start or just the comp?

Could be the indoor unit is either not draining properly (water) or the float switch thinks it`s full of water.

Could be a sensor not reading properly

Or the unit could be tired and in need of a holiday.. like me!

[Temprite]

Botrous.

What brand and model is it?

[botrous]

Guys , the unit starts occasionally , and when it doesn't start , 2 leds flashes . . . the unit is monophase , for the trade mark it's cheepos . . . and no contactor for the compressor , all the wiring is correct . when it starts all starts when it doesn't nothing starts , not the indoor fan , not the outdoor fan , not the compressor .....
Line 1 and Line 2 that supplies the compressor with power both are phase (the test screw driver lights and the voltage between both of the lines is 0 ). . . when the unit starts the voltage between the lines becomes 220 V

The 2 leds that flashes are the defrost and the run leds . . . . . . . .

Any suggestions . . .

[techguy]

Sounds like a bad connection on the control wiring giving you an intermittend fault. Mini splits usually lock out if theres no communication between the outdoor and indoor board. thats assuming there are electonics in the outdoor unit. If not you have just wasted 1minute reading this post:-) throw in a new cable. See if that resolves the issue.

[Temprite]

Botrous.
Didnt get the brand of the a/c.

How many times a second are the lights flashing?

Had a Gree a/c not coming on sometimes because on heating the indoor ambient sensor was retaining heat from the indoor coil and was not indicating proper room temp. Moved sensor away from coil slightly, no problems.

[Peter_1]

Bad soldering on the backside of the PCB which makes contact occasionally..?

[benijoseph]

(]Bad soldering on the backside of the PCB which makes contact occasionally)

U R Right peter . Dry soldering on the pcb might
be the problem. shake the PCB U will know the result?

regards,
beni joseph.

[Abe]

I had a prob with a cheapo once, ( my first and last time I bought El Cheapo......

Prob was remote controller...........I changed it..........worked good after.

I say, try new pcb board, or remote controller.

[botrous]

Well , i saw the unit again today , the probelm was a deffective indoor fan , the pcb detects that the indoor fan isn't working and stops the ac ... but what i want to know is how the pcb will know that the fan isn't working ? assuming that a device in the pcb will mesure the current that the motor absorbs .. well a loked motor absorbs current which makes it difficult to the pcb to tell if the fan is working or not .... does it rely on the air return sensor ? anyone has any idea about that?
when i pushed the fan with a screwdriver the motor started and the ac worked ... though that maybe the capacitor on the pcb is deffective so i wired in parrallel a 1.5 mf with the exsisting one , nothing happened same results ... so i concluded the motor is deffective , now i remember , i had the same problem on a samsung 18000 btu about 3 years ago

[Temprite]

Well , i saw the unit again today , the probelm was a deffective indoor fan , the pcb detects that the indoor fan isn't working and stops the ac ... but what i want to know is how the pcb will know that the fan isn't working ? assuming that a device in the pcb will mesure the current that the motor absorbs .. well a loked motor absorbs current which makes it difficult to the pcb to tell if the fan is working or not .... does it rely on the air return sensor ? anyone has any idea about that?
when i pushed the fan with a screwdriver the motor started and the ac worked ... though that maybe the capacitor on the pcb is deffective so i wired in parrallel a 1.5 mf with the exsisting one , nothing happened same results ... so i concluded the motor is deffective , now i remember , i had the same problem on a samsung 18000 btu about 3 years ago

There is a sensor in the fan motor that counts the motor revolutions on some models I think it is called a hall ic.Pretty basic explanation not exactly sure how it works without reading service manuals.

[botrous]

Temprite , this ac is a cheepos , i don't think they would bother them selfs and put such sensor ..........

[benijoseph]

Mr,BOT.
I think U R afraid of touching PCB , Fan motor
if its works even once , it will only a loose connection from
the PCB .If the remote is put in auto mode and the eva--ter
temperature is very low, fan will start very slow till the temp of the ev-ter goes up,
If indoor fan is defective , your out unit must
work? even it is not working in your case. SO CHECK PCB AGAIN OR KEEP HOLDING THE IN DOOR FAN MOTOR WITH U R SCREWDRIVER OR A CROWBAR!
with kind regards,
beni joseph,

[botrous]

Dear Beni . . . .
I'm not afraid of anything , but i'm trying to solve the problem in a scientific way , not by changing parts and testing ....
If the Indoor fan isn't working the some models will stop . . .
And for if it starts once and then didn't and then started , well man you judged it's the pcb , the pcb outputs are in good condition , the capacitor is good and the motor will start if only i give it a little push , then lets think about the motor start winding . . . am i logic or NOT ???
For your informations , I changed the motor and the unit is working properly ....
So man don't always judge things on the appearence or on the first sight , try to dig a little for some informations and you will find what's deffective .
Now no flashing lights and the unit is working very properly....
Besides I'm not the kind that escapes the problem , i confront it and try my best to fix it .
And my screwdriver that you insulted is a major part of my tools . . . so if you don't appreciate a screwdriver for what it does for you , try to mount a screw with your fingers, then you will realize how a screwdriver is usefull...

Cheers and best regards

[frank]

Hi Botrous

I think maybe the indoor coil sensor stopped the unit. If the fan is not working and the comp starts then the coil will get below freeze point quickly.

Just a theory - without specific details of the unit

OOps! Just read your last post about the defective fan

[botrous]

Hi Frank . . .
The fan motor as i mentioned was deffective . . . i replaced it and it's all ok .
But what i'm interrested in , is how this thing works to know that the fan isn't wokring ... you theory is good , but man the compressor needs 3 minutes to start between successive on/off , and the thing is that the unit started to light the leds and stopps responding after about 20 seconds , so there must be a kind of system to detect the fan . . .
still thinking about that

[malik55]

A processor knows about the fan status by two ways, either by sensing its current or its flow, if the power supply for the motor is through any C.T a coil (you have to check the board throughly) it is a current sensing type, and if there is any sensor in the air supply side it is sensing the flow.

[Peter_1]

Hi Botrous ( and others)

Sometimes, the AC engineers have very bright ideas.
In a Mitsubishi VRF, there is somewhere on the drawing a little capillary tube with just afterwards it an expanded tube and a thermistor. I couldn’t figure out why it was there and what the purpose was of this set-up.
I asked someone of Mitsubishi what the reason was of this capillary injection.
He told me that this simple set-up calculates the evaporating temperature and evaporating pressure. It was a cheap way to determine the pressure instead of an expensive pressure transducer.

I"m always curious how other detects something because these are mostly very simple and cheap solutions which works as good or even better as all that fancy electronics you find nowadys in all kinds of units.

[botrous]

malik55 , thanks for your interrest and your reply , if it was sensing the current , well a blicked motor absorbs current , so it should sens that there is no problem , unless it have a limit , in which the board will block the system is the current is ober the rated current which i will check . . about the sensor for the air flow there are 2 sensors , one for the return air temp , and one for the coil temp , that's it or that what i could only see , i'll check this ac again , but don't rally know when and post the reply herein the same threat.
thanks and best regards

[botrous]

Hi Peter , how are you ?
I'm glad to know that you are curious about the same things as me , let's say that the curiousity of the engineer is what makes him advance in his career continously , let's say it's a kind of continuing education which is vital to be always updated . . .

The AC engineers comes always with new and cheep inventions to contribute in the units performance and lower its price . . . it's for us to figure out and ask what those new things are and how it works in order that we fulfill our curiosity and stay in the market . . . days ago i downloaded the siemens courses (that i posted their links in another threats) and i think there is a course about sensors , but unfortunably still didn't had the time to read it and review the courses from my university days . . . but in electronics and sensors , each day is a new day with new inventions....
So let's try to keep ourselves updated

[Temprite]

Boutrous how many wires were on the fan motor?

[botrous]

Hi Temprite how are you ?
well there were 3 wires for the motor and 3 wires for the speeds , that makes it a total of 6 wires

[Temprite]

I am well thanks Botrous.

One wire for nuetral?
3 wires for fan speeds?
Two wires for capacitor?

After reading Malik 55 post I remember looking at a mitsubishi indoor fan motor measuring the incoming current on the PCB.You may be able to see this on the indoor unit wiring diagram.

Is it only Daikin that use a hall ic. Maybe Frank may be able to shed some light on this.

[botrous]

Glad to know that you are doing well Temprite.
Your are right about the wires , one for neutral , two for the capacitor and three for the speeds ...
I tried to locate the dealer of those ACs , personnaly this is my first time i deal with this brand "Gold" . . . couldn't locate the dealer to get a service manual or a schematic diagram of the pcb , i looked at the pcb , and couldn't see any metering device for the fan motor current ... i tried hard to get the name of the mnaufacturer of this brand , because i think it's a local TM .... no one knows him , seems he's just a trader that wanted to make some extra money by importing a cheepos to the country..

Maybe someone of our fellows can post a pcb diagram as an example with a current metering device for the indoor fan motor so we can discuss how it works.

Cheers
Best regards

[Peter_1]

Hello Botrous: I'm fine thanks (like the weather for the moment)

I couldn’t say it better Botrous: I always want to learn new things and how can we learn better then trying to understand what others invented.

I often do some searches in the Patent databases.

That’s also why I have a very great interest in electronics and computers.
That’s why I’m sometimes – when I find some spare time - busy with programming microprocessors.
I always thought in the past that this was far beyond my knowledge because I never studied in deep electronics.
Till some companies introduced tools, programs, special microprocessors that can be programmed by anyone.
One of the world leaders in this field is Parallax in the US. They developed many years ago as systems that made it so easy that even a kid of 13 years old can start programming microprocessors.
There website is really very, very good and you can surf around there for hours if you’re interested in this topic.
They made special experimental kits and books for the students and the teachers.
And what’s so surprisingly: you can download it all for free on the net
www.parallax.com and look also for the special section Stamps in class. This shows you how easy it is to program these things. You can find there many books that can be downloaded for free. Also the programming software is free.
Some of these processors performed tasks in projects in the Space Shutlle so they must be very reliable.
But you have also www.basicx.com http://www.mcselec.com/ http://www.picbasic.co.uk/ http://www.oopic.com/

Regarding the detection of the fan: if you connect a resistor in line with the common and you measure over the resistor the voltage, then this voltage will be proportional to the current.
This is a technique used if you have a current transmitter like 4-20mA pressure transducer and the controlling device (PLC or microprocessor) can only handle a voltage from 0-10 V. So it’s perhaps done this way.

When I was in the US for my ATPL training together with my colleague – a freelance PLC programmer and a real automation expert - the instructors didn’t know our history and he told us “ You both must be technicians in real life’. If he was explaining something, we never were satisfied with his general approach or explanation. If the switch for the greens isn’t actuated, then you will think that the wheels are not fully open and locked. OK, we understood this but we wanted to see this switch in real life; he even couldn’t tell us if it was located in the engine compartment, the front or rear wheels,…so we searched it ourselves. He said many times:’ You pose too many questions and too difficult questions. A non technician pilot will always be a better pilot because he only will perform the things he learned but you will always have that need to understand everything you’re doing and that’s too much workload for your brain Just believe that it is like I said and don’t try do load you brain with all kinds of stuff you don’t need’
But I think he didn’t get the point: if you understand something, then you don’t have to learn it and store it on the HD in your brain, you feel intuitive how it works.

It’s like all those techs ho installed a liquid trap (a sifon like we call it here) at the outlet of a condenser installed on the roof. Why they did it..? They didn’t know, they did it always that way.
This is what I meant with working like monkeys in an circus act. You have to know what you're doing, not just because someone said it has to be doen this way.

[botrous]

Hi peter , Glad you are good as the weather is , beleive me the weather here (in Lebanon) is wonderful , sunny days with a nice breeze , just puts you in the mood for going to the beach , as a matter of fact for me walking to the beach , my home is less than one minute walking to the beach a relax , but my brain never stops working even there , i want to know everything , is that a sin ???

Thanks for the website , it's wonderful as you said , i gonna download all what can be downloaded to read it as soon as i have some time .... as for PLCs , almost the same was told to me at the university , i was curious , if i do that what will happen , what about doing that , let's try this , where can i get more books about that ??? those things i used to ask , and the professor used to say Pierre can you just stick to the lessons for now ?

Maybe our curiousity is because we don't like to feel inferior in our field , i'm interrested in electricity , electronics , computers and mechanics . . . and maybe because we like to be innovative (that's something born with us i think ) .
To understand how things work is better than to memorize tasks and perform it , it lower the usage of your memory and improove your performance , same as in computers , the lower memory you use , the better your computer performs ....

Anyone who can't take a step forwards can't stay in his place , he's always mooving backwars.

[Peter_1]

We removed this new unit out of a showcase because we can't use it for our application.
The counter had to be lowered and connected to a central installed refrigeration unit, further away.

I found the system for the evaporation of the condensation water a good piece of mechanic, and you see that the engineers have listened to the field guys.

It also helps the condensation when surrounding temperatures are hot.

IN the lower reservoir, there is an electrical resistance, float actuated.

[Peter_1]

Hello Botrous,

Have you read something from the Stamps in Class series?
It's in fact realy simple, isn't it?

I bought from them via their Dutch supplier a BS2P40 professional starter kit.
The smaller components you need for the different electronic circuits came from Farnell UK, they deliver for free, even one piece of a voltage divider.

I printe dout all the manuals.

Have also once a look at http://www.emesystems.com/BS2index.htm a person who implemented the STAMP processor very succesfull in commercial products and he realy helps many for free when you encounter troubles while programming
http://www.rentron.com/
http://www.phanderson.com/ very good website of a professor
http://www.hth.com/losa/
http://www.nutsvolts.com/stmpindx.htm
http://www.dontronics.com/rtc.html
http://www.whimsy.demon.co.uk/sircs/index.html

[botrous]

Ya Peter , i started to read the stamp , and i'm really enjoying it , the dealer here , said that he will be glad to support me different kind of parralax products even in minimum quantities . . .
I will do some tests on them . . . and see how far i can go
You will be always updated on my evolution on those systems . . . maybe i may need some help , maybe we can find useful application for those controllers . . .
I will save those links for further reference . . .
Thanks for your help Peter

Best regards
___________________________

[Peter_1]

Read also once in their forum.
If you post a question, within some hours you will find and answer.

I talked once with Chemi about a great idea I have for it in the refrigeration field. But this project is beyond my knowledge.

But it's not that difficult - I haven't tried it yet - to control an EEV, especially those with a stepper motor like Sporlan - control SV, defrost cycles, ...

If you look also once to the www.basicx.com/Products/BX-24/bx24compare.htm site and compare the Basicx with the Stamp.

You will see that it outperforms by far the Stamp everywhere but...it's not that good supported and less documented.
But it's cheaper, faster, can perform floating point math, has 8 analog inputs(!),...

And something complete different now, the cheapest PLC we sometimes use www.tri-plc.com.
Very reliable units.
Software for free, PID integrated, LCD driver build-in, can be connected to the www, different units can be connected together in a master-slave set-up,

[botrous]

Thanks for the information Peter , i'm getting involved with the parallax controllers in a very fast way . . . and i will see the other when to make a comparision . . .
The project you are talking about is nice , now it's no doupt without my knowldge but who knows , curiousity could lead me to the unkown.
I will see the PLC website and see where it's gets me to . . .

Best regards

[macgyver]

Hi,

Did you manage to find a clear answer to this problem.
I have a unit that does the same thing (Gree KFR-80)
It registers having been turned on, flashes a couple of times and turns off.
It happens only in cooling mode and only occasionally, pressing the on button a second time usually turns the unit on.

I also have not been able to obtain a manual for the unit or the controller, if you know of any links please post, all I could find was this sales spec brochure here (you will have to type this in your browser as I cant submit a link yet)
www . dealquip .com .au /brochure / 80pwnan1.pdf

I would like to get a manual so I can see how to adjust the defrost cycle (measured or timed?)
and I have also heard there is a static pressure adjustment on this unit. so I would like to see how to do this

Any info appreciated
Cheers
Mac