Freezer issues

Discussion in 'General Brewing Discussions' started by Trialben, Sep 17, 2022.

  1. Trialben

    Trialben Well-Known Member

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    Gday brewers.

    To outline objectives here.
    Hopefully bypass chest freezers thermostat with STC1000 thermostat.

    As is I'm using a stc1000 inline with freezers thermostat to switch on compressor.

    Power into freezer then power bypass up into Stc1000 in cabinet to cold relay which returns to power freezer.
    20220917_095333.jpg
    I've got the freezer thermostat set as cold as it goes so in theory the -5c that the stc is controlling should switch without any issues.
    20220917_094710.jpg
    This is by bypass wire hooked into that black box top right
    Freezers thermostat is blue arrow.

    I've had the freezer for atleast 5 years and have run it like this the whole time
    Recently I found the stc cold relay would be on but the freezer wouldn't be running (seemed to me like it's thermostat was switched off preventing the compressor from.l firing

    This is the freezer specs 20220917_095426.jpg

    Looks like it's playing game this morning lol but still to unreliable.

    20220917_094915.jpg

    That's the temp sensor or (thermistor?)
    That black box us sorta the wiring Junction
    I just gotta figure out where them wires go so I can wire them via the STC cold relay wires instead
    That capacitor is probably for the compressor motor?

    Anyhow I think this may have confused you more it's hard to see from just pictures

    Another option is forgoing the STC all together now that I've added more glycol to the chamber it shouldn't freeze if I just use it own controller but I think bottom line it's playing up.

    What do you rekon ?




    If I get a new freezer it's 500$ ish I'd need to match the dimentions because of my cabinet build lol.

    Anyhow enough rambling.
     
  2. The Brew Mentor

    The Brew Mentor Well-Known Member

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    Back when I used one, I just plugged it in and played the freezer and or heater into the controller.
    After a few beers, I can't wrap my head around what you have going there.
    Maybe I'll look at it with a clear head in the morning.
     
  3. Trialben

    Trialben Well-Known Member

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    Pretty much exactly what you did I've plugged it In as in wired it inline.

    Yeah I thought this might be a bit confusing :p.

    I run this plugged in for a few years then I wired it into the freezer housing then when I built the chamber I wired it into the cabinet
    20220917_104253.jpg

    20220917_104305.jpg
    Just power wire up to stc and return to power freezer via the cold stc1000 relay.
    Convoluted but means only one plug goes to the wall.
    20220917_104517.jpg
    That's the freezer power cord it just loops up to stc in cabinet.
    That fan is to cool compressor its piggy backed on the cold relay stc switch.

    You know it could be as simple as one of my active wires not being screwed in right and after mucking around in there it's come good
     
  4. Minbari

    Minbari Well-Known Member

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    most compressor type coolers (freezer or fridge) have a couple safeties. one is a pressure cutout that keeps the compressor from coming on immediately after it has been running. this lets the coolant condense back to liquid and helps save the compressor.
    the other is a temp sensor on the cold side to keep it from freezing up. too much ice forms on the coolant lines and it will turn the compressor off to let it defrost.

    the STC has a compressor timer biult in to it to allow you to keep from turning it off and back on instantly. it is usually set to 10 minutes by default. when it is in delay, the little LED that comes on will flash until the timer expires.

    if the other sensors on the system are causing the unit to turn off, that might not be a bad thing. but you can defeat them, by either pulling off one wire or shorting it together. you just need to take a DMM and see if it is a normally open or normally closed sensor.
     
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  5. Trialben

    Trialben Well-Known Member

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    That's what I was hoping ish just to cut the freezer thermostat out of the equation altogether.

    My stc is set at 2min compressor delay.
    You know what but it's running good now not sure if maybe it was one of my wires just not connected and I've bumped it back in.
    Man if I don't have to go Dicking around in there I don't want to
    Setting it to -6.5 it's playing game 20220917_105714.jpg
    I'm not fermenting anything ATM so will just monitor it and see what it does.

    One other thing is I do just have my stc sensor wire taped to side of freezer housing I don't notice it swinging temp to much but maybe this is where the freezers compressor delay might be overriding the stc I'd it's switching on sooner than it's inbuilt compressor delay:confused:.
     
  6. Minbari

    Minbari Well-Known Member

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    definitely could be.

    there is usualy only one wire on the thermostat that tells the compressor to come on. you could bypass it pretty easy, but just setting it to the min temp should have the same effect, unless something on the cooler is going wonkey.
     
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  7. Trialben

    Trialben Well-Known Member

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    Yup OK will just monitor it .
    Now there is no fermenting the chamber might settle down too.
    Cheers Minbari
     
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  8. RoadRoach

    RoadRoach Well-Known Member

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    What @Minbari said about setting the t-stat to min setting x2. That way, if the contacts in the STC weld, there isn't a problem with toasting the compressor. What he said about the refrigerant condensing is exactly opposite. Gas is compressible, liquid is not. If the freezer isn't getting enough heat exchange between the evaporator coils (inside the box), they will ice up, and the refrigerant will not evaporate (as the coil name suggests it should) thereby will not absorb heat and cool the chamber. If liquid makes it back to the compressor on the low pressure (gaseous) side, it could wreck the compressor if liquid goes into the compression chamber, much like hydrolock on your car with a leaking headgasket. Turning it off (by means of a pressure switch in the low side line) allows all the high pressure (evaporator side) to return to a gaseous state and equalize with the condenser side. High pressure gaseous refrigerant is pumped into the condenser where it gives off heat, then travels through to the evaporator via a dryer and filter through an orifice which regulates how much gas is allowed to go through. As the gas decompresses (less of it on the Low-Pressure side of the orifice) it will absorb heat. The compressor should NEVER receive liquid refrigerant. Much akin to finding a stump on your 4-wheeler when that happens. It will stop very quickly, and likely blow the headgasket if not split internal parts. I've seen the insides of one when it grenades. It ain't pretty. The refrigerant is generally used to cool the compressor and motor inside the nifty little can, along with a small amount of oil. The oil is dissolved in the refrigerant to keep the compressor lubricated, not unlike mixed gas for a 2-cycle engine.

    But, as @Minbari said, the wire you took out to run from the STC output back to the thermostat can just be connected to the other wire going from the thermostat to the compressor (or the next safety as the case may be). I'll sketch a copy of that diagram from the freezer nameplate, and get back to you with a mark-up where to put the contact for the cooling output. What you're basically trying to do is replace the functionality of the freezer's thermostat with a much more accurate and programmable thermostat. Shoot me the diagram for the STC, and I'll even include terminal numbers for it on the diagram that I sketch up for you.

    You are correct, the capacitor is for voltage stabilizing on the compressor motor. When a motor starts, it will pull voltage down pretty low. The capacitor prevents that. Has nothing to do with the cooling efficiency or control, but can make the compressor motor overheat if it's kaput. They usually swell up and turn brown when they fail, or the freezer will start tripping external electrical protection. If they fail open circuit, the thermal overload on the compressor will kick it out before it can cool the freezer.

    A good idea if you think a loose wire might be the issue is to unplug the freezer and tighten every connection and make sure you didn't get insulation in a connection. A bad connection can not only stop something from working correctly, but it can also overheat and start a fire. Again, your current is a lot lower because of having 240V power, meaning it is less likely to overheat, but not unlikely. I noticed at least two terminal strips in the photo. Wouldn't hurt to check every connection there and anywhere else that has a quick-disconnect or screw type connection. If you're not comfy with doing the electrical stuff, get a sparky mate to come over and give a hand. Surely you know at least one electrician that likes a good beer.
     
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  9. Donoroto

    Donoroto Well-Known Member

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    Your setup is right: just set the thermostat as low as it goes and let your controller manage temperature.

    What problem are you trying to solve? Does it not keep temperature properly?
     
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  10. RoadRoach

    RoadRoach Well-Known Member

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    The black plastic box on the side of the compressor appears to be the starter (Item RT on the diagram) for the motor as well as a junction box for that, the compressor motor, and the capacitor and the wiring to the thermal overload. The thermal overload may also be in that, but the diagram suggests it's mounted remotely, and quite likely right behind the thermostat, judging from the wiring photo. Is the thermostat mounted on the front wall of the freezer, and is that the green light (HGN) mounted right beside it to indicate power is on the freezer? The two terminal strips, I'm assuming are for the two cords going up to the STC? Not quite sure where the incoming cord shows up. Or is that the black cord i see also going into the junction box? I see one new blue wire, and one new black wire coming off one of the terminal strips, which I'll assume is the cord coming from the STC Cooling output. All the green wires with yellow tracer SHOULD be grounds and end up attached to the frame somewhere. The wire colors I see in the cords is a European standard, blue and brown for hot legs, and green/yellow for Earth or Ground. The new black wire is spliced with a red wire coming out of the compressor, and the new blue wire is spliced to the black wire coming out of the compressor. The two taped connections are the ones giving me a little heart burn. I'm sure it's an optical illusion, but it looks like the Earth/Ground coming out of the compressor is connected to one of those. Or is that just a yellow wire? Tugging on the wires a bit would tell me more, but I think I've got the gist of the mods. I probably have enough to redraw the circuit diagram, but it would be real nice to know how things are connected inside that junction box. It wouldn't be the first time I've seen the intended purpose/function achieved without the wiring being exactly like the provided diagram. That said, what I think I'm seeing in the wiring photo it looks like the contacts for the cooling might actually be in the hot leg of the compressor AFTER the M symbol. IF that were the case, and the RT picked up, the compressor would not run despite the thermostat in the freezer telling it to. But you'd see that on the STC display, too. Unless the cycling was causing the RT and the STC to conflict with each other. Then who knows what would happen. Need to make sure that the contacts for the STC are between the SAT and F devices on the diagram if you want to override the thermostat with the STC.

    The thing you're calling a thermistor is actually a capillary tube that should go to the thermostat via a small tube that might resemble a wire. Quite likely, it's insulated, but for ambient heat, not electrical insulation. If it were a thermistor, it wouldn't need thermal insulation where it comes through the wall, and it would have two wires on it, minimum. A little caulk and it's done were it a thermistor. A capillary tube is a pressurized device that operates a spring-loaded diaphragm in the thermostat (spring pressure is changed by turning the knob on the control). You cannot buy the thermostat without it, or it without the thermostat. They're factory sealed units, and I have no foggy idea what gas is used in them. As the gas in the capillary tube gets colder, the gas contracts and the pressure drops and allows the spring to overcome the diaphragm and open the contacts. This is why they're notoriously inaccurate after a very short lifespan. But, they're reliable proven technology, cheap, and according to at least ONE engineer and 5 bean counters, the ONLY way to do it. Electronic temperature sensors are a lot more expensive, but that changes daily. If you save half a penny on a million units, well, that's $50,000.00 saved, isn't it? Redesign, testing, and UL approval will knock a big dent in that $50K, very quickly.

    Appliance manufacturers have their own way/standard of drawing things. The RT device is the run relay, which may also have a built in run timer on it. It's basically paralleled with the compressor motor, and if you look at the compressor motor symbol (M), it shows what looks like a contact symbol in the circle. That would be the contacts from RT. It doesn't show the motor windings. The contacts and motor are shown as one symbol because the RT is mounted on the side of the compressor.

    The overheat/overload protector (F) is sometimes mounted on the high-pressure line of the compressor. As flow reduces (because no more refrigerant can be forced through the orifice) the refrigerant temperature will go up and shut off the compressor. This does two things. It shuts the compressor off and forces you to wait until the refrigerant cools enough to start the compressor again. This is also sometimes done with a pressure switch on the low-pressure side (evaporator coil) where the pressure will get too high if the refrigerant cannot evaporate quickly enough to return to gaseous state. Few inexpensive appliances actually have a 'start inhibit timer' so much as just a thermal device you have to let cool down. Some may have a built-in time delay to allow the run contacts to close again after some delay., but that's typically on more expensive units. I've seen both ways, and if you want it done 5 ONLY ways, just ask 5 engineers. If you want to start a good argument, just ask a Chinese engineer. No offense intended to the Chinese, just a personal observation and experience. They'll very quickly tell you that you don't know what you're doing if you question a Chinese design.

    Taping the temperature sensor to the side of the freezer may also give you false ambient air temperatue readings if you're using it to control air temperature in the chest. I elected to use the built-in thermowell on the fermenter so I watch batch temperature, not air temperature. There could be 3-4 degrees difference while fermentation is at its peak. But if you're happy with chest air temperature, then I'd probably find a way to mount it on a wand to suspend it out in the air. Obviously, that presents its own set of problems for handling the kegs in and out.

    I see three different STC's. Chamber, Fermenter, and Glycol. Do you switch them based on what you're trying to cool? How are those contacts wired together for compressor run permissive?
     
  11. Trialben

    Trialben Well-Known Member

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    Yes one terminal block is power up to stc the other is the return power then on to freezer.
    It's actually keeping temp nicely today set at -8.5c
    I don't know what was going on honestly but it seems that the freezers thermostat must of be switched off when the stc was switched to cool.

    Anyhow it seems a few freezers have been on the blink of late. I was watching Martin keens from hombrew on YouTube last night his VB brew clone (not a clone at all lol) his freezer had died.

    Thankyou for your detailed response everyone.
     
  12. Trialben

    Trialben Well-Known Member

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    It wasn't but now it's back on track :)
    20220918_072528.jpg
     
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  13. Donoroto

    Donoroto Well-Known Member

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    Glad I was able to repair it. :rolleyes:
     
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  14. west1m

    west1m Well-Known Member

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    I didn't see it mentioned but most freezers have defrost circuits that stop the comperssor ,fire up a heating rod on the evaporator coil for a few minutes to keep it defrosted.
     
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  15. Trialben

    Trialben Well-Known Member

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    Just a recap on this thread I started on a whim thinking my keezer was on the blink.
    Looks like it's a human error situation of course.
    Well more like a temp probe placement situation I placed the temp pobe previously high up about half way in the freezer and had it set at -5 well after putting the temp sensor prop down the bottom setting at -9c it's running when cooling is called from the STC.

    I think it was below the preset inbuilt low thermosetting setting so it was being over ridden.

    I'll double check were I've got the freezer thermostat set to I'm sure I would of turned it as low as it would go but now I've got it mounted behind the cabinet it's not so easy to just check and see.

    Thanks again forum members for your replies
     
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  16. RoadRoach

    RoadRoach Well-Known Member

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    Not if they aren't frost free. Strangely enough, Frost-Free is still an option on new freezers, and typically will add at least $100 to the price. Mine is exactly 2 days old now, and is NOT frost free. I have a big chest type (21 cu ft) that isn't either. We have to unload it, turn it off, and thaw it out every 2 years or so because the frost will build up and reduce the efficiency. That's usually purge time, too, to get rid of all the old stuff and reorganize it. Some, as you say, stop freezing, but they work a lot like heat pumps and just reverse the refrigerant flow to warm the inside skin of the freezer long enough to melt the frost. With frost free boxes, it's more important to not put food items against the wall because it will partially thaw and refreeze that item every time it cycles. Any freezer works better if there's air flow around the walls, though.

    A lot of them have anti-condensation heater strips in the door gasket as you say, simply because it the condensate freezes and builds up there, the problem will just snowball (pun intended). But those typically are on any time the compressor is running. Heat also keeps the door gasket from molding so bad because of constant moisture presence. This little fella doesn't even have that, but it does have a very wide magnetic seal on it. If I open it for a few minutes, then close it, it chills the air so fast that it pulls a vacuum inside making the door VERY hard to get open. It takes both hands and considerable strength to pull it back open. I'm guessing it'll eventually equalize if I let it sit long enough. Not so bad at the moment the way I'm cyclically running it for fermenting temps, but I can see a cold lagering being fun to check on.

    Looks like I've got this puppy planed out now. Temp is 62.7 this morning with a 63 setpoint and 1 degree deadband. Was a good learning curve (and a lotta stress) trying to do this with ice in warm climate. The bad part is it really isn't "summer" here now. The daily highs right now are about what some of our nightly lows were just 2 months ago. No way I could have kept up with that. Learned my lesson about being stingy (again). Onward and upward to adding pressure transfer and fermenting to the arsenal now.
     
  17. Ozarks Mountain Brew

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    Mine turned out to be a buggy starter relay, I turned it off for a week then plugged it it into the wall and it works as a freezer, not sure if it will last as a fermentation system without replacing parts
     
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  18. Trialben

    Trialben Well-Known Member

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    Can't replace relay unit?
     
  19. Ozarks Mountain Brew

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    Not sure if it's inside the compressor unit or not, it's an igloo freezer
     
  20. Trialben

    Trialben Well-Known Member

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    Hey guess what I think I mighta worked out what's going on with my glycol freezer.
    Well I've got the freezer thermostat set on "Min" thinking that's the minimum temperature well I had a looksie at the manual tonight after witnessing the freezer still not being on when the stc was calling for cooling at -10

    Check it Screenshot_20221008-204441_Samsung Internet.jpg

    Sorry but that's reverse psychology man!

    Heads up to anyone else using a freezer maybe you mightnt have the inbuilt thermostat set to its minimum setting or should i say maximum cooling setting:confused: lol!

    As soon as I set the dial around to Max guess what the compressor kicked in yay!
     
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