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1999 Bev-Air BM23 Not Running Cold Enough

Discussion in 'Home Bar' started by makats, Apr 12, 2019 at 8:02 PM.

  1. makats

    makats Initiate (0) Friday

    Hi All, new to this forum and to the home dispensing.

    I've just picked up a circa august 1999 (as per bev air customer support) BM23, and I had it run with thermostat set on 7 for ~16 hours with a 5gal bucket inside. The unit seemed to be cooling (I saw some condensation on the tower, and the compressor was cycling fine, about 2-3 times in an hour or so), but when I checked water temps in the bucket after about 16 hours, the temps were only ~47F, and the inside thermometer was showing ~55F (although when I opened it the compressor was off, and only the fan inside was spinning, and I did open the door during the night a few times to check on diameter of replacement tubing I will need to order). When I turned the tstat to 9, the compressor turned right back on and I have it running like this right now for another 8 hours to see what the temps are when I get back home after work, but to me it seems like it should'be been much colder on tstat set to 7. I texted Bev Air tech support with a brief description, and they suggested bad thermostat. Does this sound right to you or perhaps you could help me with troubleshooting it a bit more? Should I try jumping the Tstat first before I order a replacement?

    Just to recap:
    Thermostat set on 7 - 5 gal bucket with water is at ~47 after 16 hours.
    The compressor turns on, runs for a while and cycles off, then turns on again and the cycle continues normally
    The condenser fan turns on each time the compressor turns on
    The evap fan inside is running 24/7
    No loud noises etc. coming from the fridge
    The door seal is shut close, no light coming out with bright LED inside in dark room
    The unit has been sitting in storage for the past 2+ years

    I would really appreciate any help I can get. Thanks
  2. PortLargo

    PortLargo Devotee (441) Oct 19, 2012 Florida

    A couple of things: Waiting 16 hours is not nearly long enough . . . it's not like you are trying to chill a bottle of beer. You probably didn't measure temp when you started, but to chill 5 gals I wouldn't expect much more than 1°/hr (many variables involved). Have you calibrated your thermometer? In a large glass of ice slurry (just enough water to immerse temp probe) check your reading, should be a hair above 32°.

    When running, your compressor is putting out it's maximum amount of cold air, i.e. it's wide open just like Kyle Bush at Daytona. Probably something like zero degrees coming off the evaporator (that's a guess) and expect that whether setting is 1 or 9. The numerical setting just determines the on/off points to maintain a constant interior temp of the liquids (just like your kitchen refrigerator).

    Ignore air temps, they will vary on where you are in the run cycle. The only thing that matters is your liquid temps and they move very slowly. Ideally, after 2 (3?) days the liquid temp will stabilize and unit will run a little less. With some trail and error you can figure out which numerical setting gives the proper temp. You'll find the liquid temps remain pretty much stable when unit is running or off, just like the milk in your fridge.

    Patience is a virtue as nothing happens very fast when chilling liquids. You are smart to start the learning process before any precious beer is put at risk. You didn't ask, but if not familiar with carbonation charts, now's the time to dive in. Several posters here have experience with the BM23, they will probably chime in with more specific tips.
    billandsuz likes this.
  3. makats

    makats Initiate (0) Friday

    Thanks for the reply!

    You were partially right, after 48 hrs the water in 5gal bucket is at 35F and seems to be keeping the temp stable. I am testing the water by both contactless laser thermometer (non-calibrated) and also have a 2-probe calibrated wireless thermaprobe inside (one inside bucket and the other one just in the cabinet).

    My concern is that my understanding is that BM23 is supposed to give a 35F temp on 4-5 settings, but mine is set at 8-9ish... Although it does not run for long at all. I would say that the compressor runs only for about 30% of time, if not less, the rest of the time just the fan inside is running and nothing else. So it might be that my tstat is giving up so I might just end up swapping it for something digital to have better control.

    I've also discovered that my thermostat's probe was not touching the back plate but was rather bent and just hanging in the air mid-cabinet. Can somebody confirm that the tstat probe needs to be in direct contact with the back plate?
  4. billandsuz

    billandsuz Disciple (384) Sep 1, 2004 New York

    First, congrats on picking up a BM 23. The fact that you have a 20 year old kegerator up and running is why we around here promote the name brand equipment. With very little routine maintenance that unit will be good for another 20 years. Easily.

    The T-Stat probe should have a plastic clip to hold it in place. It may have been lost over time. No worries, as long as it is not directly in front of the fan or touching the coils it will be fine. Remember as @PortLargo said the T-Stat is merely an on-off switch. It does not change the temperature produced just the frequency. So we want it to tell us the ambient air temp inside the box and not the temperature of the air being produced.

    If you decide to replace the T-Stat don't buy a digital unit. Well do what you want, but the BM 23 has a direct drop in replacement available. There are a few different models available but if you remove the original you'll be able to order an exact replacement. That's why this is good equipment. It works and they don't change it because it really works. It's also a pretty cheap part.

    Or, if you can get a steady 38 and the compressor is not running all the time, just let it be.
  5. makats

    makats Initiate (0) Friday

    I was amazed myself that a 20-year-old unit would be still running strong (and quite! I read so many complaints that they are loud, but this thing is almost as quiet as my brand new Samsung two-door fridge), but it just seems like those things were built like tanks and as you said, if something does go wrong I expect to be able to service/replace parts myself. I see what you saying about getting the stock analog t-stat, and I might just go this route if and when I decide to replace the T-stat. For right now, the 5-gallon bucket was hovering at 35-37 degrees on the 8ish setting, so I decided to go ahead and get all the new lines ordered, and the unit cleaned for a first keg run. If it will be able to keep the beer in a keg at that temp for me consistently I am not going to mess with it right now, as this should be sufficient for me. And as I said, the unit does not run for long at all and there are no signs of ice on evap coil or lines near the compressor, it might be that there is a slight issue with either the thermostat itself or its probe, but as I said right now it is "good enough".
  6. billandsuz

    billandsuz Disciple (384) Sep 1, 2004 New York

    I'm thinking if you take a sharpie and cross out the numbers on the thermostat dial and write in new numbers, your machine will hold 38 at the #5 setting. Then it will be working perfectly again.
    It's just a thought.

    To expand on the digital t-stat, they do work. Two of my beer fridges have them, a Ranco and a Johnson A 419. But you will have some wires hanging around if you use one. And they require a bit more understanding to get them to do what you need to. Basically you do not really need the flexibility of an outboard digital temp controller. Also cost more. But the installation is very easy. Nothing to remove and replace.

    There is one big issue here though.
    An outboard thermostat will not get the temperature below what the internal thermostat allows.
    If the coldest setting on your kegerator gets to say 38, and you set your external thermostat to say 34, the inside thermostat is going to shut down the compressor at 38. The outboard thermostat works by cutting the power to the whole show, as if the plug were pulled. So it will force the compressor off at the set point, but it can't over ride the internal thermostat which is acting as a switch to turn of the compressor at 38.

    So if you want a keezer to maintain 38 or a fermentation chamber to maintain 60 then yes.
    But otherwise the outboard is not a solution here.

    IceAce and PortLargo like this.
  7. makats

    makats Initiate (0) Friday

    The numbers on the t-stat don't bother me much as long as the unit is operating at the desirable temps and it is not harming it in any way ( I would be concerned if the compressor was running constantly etc, but since this is not the case I am not).

    I also see your point about digital t-stats, and right now I don't really need all the bells and whistles that a digital t-stat might provide, I just want some cold beer :slight_smile: I will most likely have to get a separate fermentation fridge once I get more into brewing and lagering, but right now I am just trying to weed through the plethora of places around me that offer nothing else in kegs bud budlight, coors light, and michelob ultra.... It seems like it is much harder to get some craft kegs in the rural south :slight_smile: