Bm23c thermostat issue?

[Jack312]

Hi, I’ve been doing lots of reading and I haven’t found a good answer, hopefully someone can help me with this.

Recently bought an old beverage air bm23c, was built 3/14/77 it was a wood panel design that someone painted, took me too long to figure that out, but otherwise good condition.

So I plugged it in and it did get cold, 12 hours later when I came back to it was warm. I heard the clicking noise so I replaced the starter relay but not the overload, while I was down there I cleaned the coils out really well and the area in total. Found a few dead mice..yay. Plugged in the new starter relay, it ran like a top all day. Put in the wall thermometer that we have in the shop and it gets coldmid 20’s on 7, I know water temp vs air temp is different I’ll get to that tomorrow. Seals up ok around the door and such. Came in this morning, heard the clicking sound again and inside air temp was 60+. So I unplugged it, an hour later plugged it back in and it’s running like a top. I have the t-stat set at 4.5 out of 7.

My question is, does this seem like it is a thermostat problem?

Compressor and coils turn on and get warm in the back, all fans come on. Compressor also seems to cycle ok. Not on too long or off too long. No weird noises.

Also, it seems that I don’t have a thermostat wire coming out to test the temp. I’ve seen pictures of others bm units with it. Mine doesn’t seem to have ever had one.

Thank you in advance for the help. I am super new at this but a proficient DIY-er.

 

[day_trippr]

On a unit that old I would expect to find a capillary tube leading to a strategically placed bulb and a mechanical thermostat at the other end. I doubt those are likely to "chatter" but I suppose anything is possible.
Is it possible the compressor was in a thermal shutdown state during the clicking thing, and unplugging it let it cool down enough to run again?

Cheers!

 

[Jack312]

That honestly makes the most sense, I’ve never heard of a compressor going into a thermal shutdown, but I’m not a refrigeration tech. I pulled off the cover and this is what I found. Every thing seems to be solid and intact. The drip tray is the worst of it and it is only lightly rusted, a little bit of sanding and a shot of clear should do the trick. Anyone know how to replace the back drain hose easily? Also, the ice forming in one of the photos was me turning on the unit to see if the coils got cold. They do.

So my theory is that use is the solution. The more I use it the more the problem will go away. Currently it is off and dismantled, so I will remedy that soon.

The guy I bought this from had it in his shed out back and turned it on every so often for a party or two a few times every year.

 

[Staticsouls]

I have a similar beverage air and I hooked it up to an inkbird type controller instead of replacing the thermostat, and it works fine.

Just in case you get lazy