Tagged: Atosa Msf8302
MemberJanuary 4, 2021 at 12:28 am
It’s been like a month that i’ve been watching it but can’t figure it out what could be wrong with it. It cools and keeps the temperature for few hours and all the sudden stops cooling and temperature goes up for hours , when i touch the compressor it feels hot and running also the coil fan works perfect, coils are clean everything seems to be working fine but just not cooling sometimes .
I figured the freon should be fine since it cools for hours sometimes and it is not that old ,also all the settings on the meter are set correctly, we bought it in 2015 brand new.
Any idea what could it be?
MemberJanuary 4, 2021 at 9:23 am
First off, this type of cabinet is prone to overloading. Make sure there is air clearance in both the front and back of the load inside. Especially the front. I’ve come across many that the door will not fully seal due to load to far forward or to big. Next, always make sure the pans are in the top, even if they are empty. Now when it does this is the compressor running or tripping on overload/hard start? Is the evaporator coil (the one inside) have any ice or heavy frost on it. Often in high load times it will run to long and ice up. Especially if there is a open high moisture product loaded or a warm product loaded. Also if the drain is restricted. You can try raising the thermostat a bit. Check the evaporator with a mirror from the drain side for this. You will also notice a reduced air flow inside the cabinet with ice up.
Another possibility is the control system. I don’t know if yours is mechanical or digital. The digital ones can have a sensing problem or relay problem. Compressor would not be running when it is rising temp in that situation. But you may be seeing it after it has risen.
Make sure to check the liquid line coming out of the high temp situation to see how hot it is. IT should be a max of 10 degrees above ambient room temp. Otherwise you have a condenser cooling problem. They use a very thick condenser (6 rows deep) that is prone to restriction. Check by shining a light thru it.
Hope this help you.
MemberJanuary 4, 2021 at 9:32 am
Is this the same unit you had the low ambient on? If so, I’d be looking at replacing a thermistor or checking the wiring to the controller and the mounting of the thermistor to the evaporator. Especially where the cable goes through the housings.
MemberJanuary 5, 2021 at 12:09 pm
Hello there , yes It is the same unit but I already figured those out , i called Atosa costumer service and we went through the all settings together with one of the technicals so i thong the thermistor is set correct now,
I unplugged it yesterday till this morning just to see if it might change anything , still waiting . The temp right now is at 42F
It’s just hard to figure it out myself, i had a guy he charged me 150$ , he said he fixed it but he didn’t, I don’t want to bring someone else before i have an idea of what’s going on
MemberJanuary 5, 2021 at 1:16 pm
And what did he do?
MemberJanuary 5, 2021 at 2:13 pm
Nothing actually, he came in while I wasn’t there he said he cleaned it and it was cooling and he left , but he thought he did but he didn’t fix the problem still doing the same , someone els said that it needs a new meter or thermistor just like you said, but not willing to pay 400$ just for that, he said 400$ just to replace that
MemberJanuary 5, 2021 at 4:09 pm
The thermistor should only be about $30 to$40 bucks. Think you need to find a more reputable refrigeration man. Contact your local chapter of RSES or a supply house like United refrigeration. They know who is good and will recommend someone local to you. A good supply house will be working with RSES with training.
MemberJanuary 7, 2021 at 1:30 pm
I already replaced this temperature control but still doing the same , the fans are working compressor feels hot and running, it will only start cooling after I unplug it for like 15 seconds and plug it back , after it reaches 35F it stops and even if the compressor turns back on it doesn’t cool, i’m wondering if it has anything to do with the component capacitor, relay component or that computer board. Not sure what else should i try next!
MemberJanuary 7, 2021 at 3:50 pm
Are you certain that the compressor is RUNNING? Not just trying to start.
MemberJanuary 7, 2021 at 4:09 pm
Every time i touch it, is hot and it has a little vibration, feels like running, i might be wrong but that’s how it feels ,
You said that the Thermistor could be the problem, i thought the thermistor is the display on the front that shows the temperature numbers and has all those settings , I changed the display but didn’t help,
Do you know where is this thermistor located and what does it do ?
I might try that next,
MemberJanuary 7, 2021 at 6:23 pm
The thermistor is a sensing device that is mounted in or on the evaporator coil to tell the controller what temperature the coil is at. Normally about a 1/4 inch in diameter and about a inch plus long with a wire cable out of it that goes to the back of the controller. It is a variable resistor that changes resistance as the temperature changes.
MemberJanuary 7, 2021 at 6:27 pm
It can ne tested with a digital ohm meter at the controller. Measure the temp at the coil, then the resistance at the controller.
MemberJanuary 8, 2021 at 12:23 am
I found the thermistor it and it works , what else do you think could be?
some guy said that it could be the defrost sensor or defrost problem but not sure how to find it or how it looks
MemberJanuary 8, 2021 at 7:48 am
It’s not a freezer, so it doesn’t have either a heater or defrost sensor in the normal form. The controller will not start the compressor till the sensor tells it that the coil is above 36 to 39 degrees F. That way it goes through a defrost every cycle. The Evaporator will get down to about 10F near the end of cycle.
Now with Dixel controllers, They are made to be able to use 1 or 2 temperature sensors. Quality units will use 2. One for the box temp and one for the evaporator temp. If your cooler does not have two, You are more likely to experience ice up of the evaporator.
But you are telling us that even if the compressor starts, it isn’t cooling till you unplug it and restart. Is that correct? Is warm air coming out the condenser before reboot? What is the temp of the compressor suction line? Any frost?
Unfortunately, Atosa does not provide much documentation or engineering. Does your machine have a solenoid valve with a separate cooling circuit for the top pan area?
MemberJanuary 8, 2021 at 11:55 am
Sounds to me like the comp is not restarting every time.
Seen it before, normally bad start components.
MemberJanuary 8, 2021 at 8:27 pm
agreed, but not what he is telling me.
MemberJanuary 8, 2021 at 1:36 pm
I think The compressor is running all the time , I checked the evaporator inside and it had very little “snow” at the beginning the compressor was running and it was really hot , I couldn’t hold my hand in it , does it mean it is low on freon?
MemberJanuary 8, 2021 at 6:20 pm
Not necessarily. How hot is it and what temperature is the suction line to the compressor?
Please don’t jump to conclusion’s or replace parts without knowing that they have a problem. The key here is to actually find the problem and correct it. You are our eyes and ears on this. So just let us know what you observe.
MemberJanuary 8, 2021 at 7:37 pm
I’m trying to do my best, at the same time trying to learn at least something on this matter as a restaurant owner. Now days is hard to find a good honest technician that doesn’t try to replace every single part till they find the problem. I’m not sure which is the suction line but I’ve touched both of them and one is hot and the other one i would say it is cold but didn’t seem could enough , the compressor runs all the time, and I don’t have anything to measure that temperature but when i touch it I can’t hold my hand in it for more than a second or two.
The evaporator inside it is not snow all the way , just a little bit at the beginning where the hose comes from the back side, i was thinking it doesn’t have enough freon to make it colder. I might be wrong. Also this compressor doesn’t have a valve to check the freon, i guess will have to add one to make sure it has enough.
This is my best bet and i could be wrong since i’m not a professional ,
MemberJanuary 8, 2021 at 8:18 pm
The evaporator inside it is not snow all the way , just a little bit at the beginning where the hose comes from the back side, i was thinking it doesn’t have enough freon to make it colder.
At what point in the cycle, after it has run say a hour?
Also this compressor doesn’t have a valve to check the freon
That is correct. It is illegal to add a tap and leave it today. Systems are sealed for EPA reasons and rarely need to have access. Not saying that there are ones that require access at times, but its not common. It also require a EPA License and a lot of expensive support equipment ready on standby. Prior to the Montreal protocol in 1992, one could do refrigeration work with less than a $400 investment. After 92 you better have at least $10,000 to get started. Otherwise you were not in compliance.
Now what we need to know is a bit technical at this point. Like compressor amps, discharge temp, suction temp, and box temp. The compressor is cooled by return gas from the evaporator. Lack of flow will feel like a hot compressor. But so will a lack of cooling at the condenser. ie. blockage, fan speed.
<font face=”inherit”>To be honest, you need to find a good tech for this. You can not personally open and work on a refrigeration unit without facing a $25,000 Federal fine </font>Licensed<font face=”inherit”> Techs get a call number to report suspected violations and 50 percent of the fine for reporting it. I don’t know where you are at, but as I previously mentioned, there are good techs across the whole country. But yes, there are also predatory techs out to take advantage of people. Like I said before, contact your local refrigeration supply house. They will point you in the right direction. </font>Preferably<font face=”inherit”> a RSES tech that holds a CM.</font>
MemberJanuary 8, 2021 at 8:50 pm
MemberJanuary 9, 2021 at 1:15 pm
Do they use a cap tube or TXV for metering the refrigerant? It is possible you have a low charge, but with a sealed system it isn’t a norm. Your picture shows that it is starving for refrigerant at the evaporator. Check the liquid line at the dryer/filter. If the outgoing side is colder than the liquid coming in, You’ll need a tech to fix it. That’s also where you can tell if it’s a cap tube system. You’ll see the line size drop to about 1/16 inch.
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