Commercial Refrigerator help needed - It cools, then gets warm?!

[ajwillys]

I recently got a really good deal on a True kegerator. When I picked it up, it was unplugged and warm. I plugged it in and cold air immediately started pouring out of it. It was very noticeably colder than the ambient air. I figured that was good enough and took it home.

Once home, I let it sit unplugged for 48 hours and then plugged it in. Again it immediately started cooling. I came back to it after a few hours and opened the door and it was warm inside. It was actually warmer than the ambient air.

I tried this a few more times and each time, it would pump out really cold air at first, but then would warm up. What's happening is that after it cools for a bit and shuts off, it seems to turn on, run for a very short time, then turn off abruptly. I think its getting warmer than ambient because the compressor is heating up one of the interior walls.

Anyway, does anyone know what might be causing this? Part of me thinks it could be something simple since it cools for awhile, but I'm wondering if its perhaps overheathing or something and that's why its shutting off.

In case it matters, it appears to be an old version of the True TDD-3. I'm not sure if that's the model number or not.

 

[malkore]

It sounds like a problem with the compressor. Since it gets noticably cool, quickly, when first turned on, I think you have enough coolant.

I'm sure someone else here with real refridgeration knowledge will pipe in, but I'm betting this thing has a real problem and that's why you got it for such a good deal.

 

[WrongCoastBrewery]

Can you hear the compressor run constantly? Or does it cycle like a normal refrigerator? I am not so sure you dont have enough refrigerant. Any dents or signs of damage around the sides?

 

[ajwillys]

It cycles on and off, but it never seems to stay on very long after the first time. It's almost like it might be overheating. I'm going to try to capture a recording tonight.

 

[ajwillys]

There are no signs of damage. It's built like a tank. I should mention the air coming out is cool, but not super cold. Just cooler than ambient. The compressor does have a fill valve on it with a large cap and a smaller one next to it.

 

[DeBrewer]

Do you have a thermometer in it? I thought the same thing with my commercial kegorator the first day or two it was plugged in but after a while it regulated it's temp better. I am using the eBay aquarium temp controllers and when it would hit the desired temp inside the temp reading would just start climbing up again until it finally chilled the box itself. Once that happened I can open the doors for a bit to mess with a keg and after shutting it can cool back down in a matter of seconds. Give it some time and check with a gauge...

 

[ajwillys]

I don't have a thermometer in it, but its not cold at all.

I watched it some more and learned a few more things about it. When you first plug it in, it cycles on for a long time and puts out the coldest air. Each cycle gets slightly shorter and puts out less cold air until it's cycling on for 20-30 seconds and putting out room temperature air.

If I unplug it and let it sit for awhile, I can repeat this cycle over again. I really think something is overheating. I'm thinking either the relay is bad or the compressor needs freon or is busted. I read online how to test to the relay but haven't gotten around to it yet. Let me know if anyone has any better ideas. I really want to get this behemoth working. It'll hold 11 kegs!

 

[dogtailale]

http://www.acmehowto.com/howto/appliance/refrigerator/refrigerator.php

I cant help much more than that.

 

[Hermit]

If it comes on, I doubt it is the relay. It would be really helpful to know how many amps it draws when running.

 

[KCBrewer]

It could be low on refrigerant, and it has a pressure cut off switch. The taps on the compressor make it even more suspect to having a leak.

Small appliances are usually sealed systems, and typically only have taps installed when someone has been into the system, like to charge a slow leak .

A pressure switch is sometimes used on refrigeration systems to protect the compressor from being run when low on refrigerant. If yours has one, it could be why it's cutting in and out. It will run pretty much how you described.

What happens after being off for a little while, is the pressure in the system equalizes between the low & high side, so it takes a minute to build that pressure back into the high side. Once it does, the pressure on the low side drops too low, so it cuts off the compressor. Then, as pressure begins to equalize again, pressure on the low side rises again, and it kicks back on.

 

[WrongCoastBrewery]

It could be low on refrigerant, and it has a pressure cut off switch. The taps on the compressor make it even more suspect to having a leak.

Small appliances are usually sealed systems, and typically only have taps installed when someone has been into the system, like to charge a slow leak .

A pressure switch is sometimes used on refrigeration systems to protect the compressor from being run when low on refrigerant. If yours has one, it could be why it's cutting in and out. It will run pretty much how you described.

What happens after being off for a little while, is the pressure in the system equalizes between the low & high side, so it takes a minute to build that pressure back into the high side. Once it does, the pressure on the low side drops too low, so it cuts off the compressor. Then, as pressure begins to equalize again, pressure on the low side rises again, and it kicks back on.

+1 to this. Be very careful snooping around the compressor if it has a leak. Freon is heavier than air and displaces it big time. People who get freon in their lungs have to be hung upside down to allow it to drop out.

 

[Hermit]

It could be low on refrigerant, and it has a pressure cut off switch. The taps on the compressor make it even more suspect to having a leak.

Small appliances are usually sealed systems, and typically only have taps installed when someone has been into the system, like to charge a slow leak .

A pressure switch is sometimes used on refrigeration systems to protect the compressor from being run when low on refrigerant. If yours has one, it could be why it's cutting in and out. It will run pretty much how you described.

What happens after being off for a little while, is the pressure in the system equalizes between the low & high side, so it takes a minute to build that pressure back into the high side. Once it does, the pressure on the low side drops too low, so it cuts off the compressor. Then, as pressure begins to equalize again, pressure on the low side rises again, and it kicks back on.

Commercial systems often have taps from the factory. Good call on the pressure switch though. Is there a schematic on the unit?

 

[Bumbler]

I'd love to see a pic of the service taps. It'll give an indication of factory install or add on by tech.

For what it's worth, here's my 2 cents.

Signs of low refrigerant charge. (most likely)

hot compressor (overloads might open)
short cycling (low pressure or overheat)
low amps (?)
high cooled space temperature
oil stain near leak

signs of overcharge (too much refrigerant) (probably not)

short cycling (high pressure)
cutting out on the high pressure switch
noisy compressor
sweating suction line
sweating compressor

signs of air in system (not very likely)

Short cycling (high pressure switch)
high amps (?)
Hot compressor

There are other indicators, but take specialized tools.

The bottom line, Sounds like an undercharge. Probably not a DIY fix.

Call your local Tech. school with an HVAC program and see if they will fix it. Odds are, they will. They love the real world experience.

 

[ajwillys]

OK, sorry I let this thread hang. I had shoulder surgery and was unable to work on it at all. Now I'm back and am ready to tackle it. I think it might be a low charge, so I took a look at the compressor. It's definitely R134a so I was going to try to fill it using those automotive kits, but the fittings don't seem to work. It looks like the thing sticking out the left side is a valve and maybe there is no 'auto shutoff' on the fitting part on the top. Here a pic:

 

[KCBrewer]

That looks to be a factory service valve, so it's not a tap someone added. You could get an adapter to use the automotive fitting you have. I believe this is the one you'd need:

http://cgi.ebay.com/ebaymotors/R134...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

[WTF_Brewing]

Is this a frost free type fridge?

I had a side by side fridge do the same thing a few years ago. Being a DIY type guy, I tore into it, and found that attached to the cooling coils is a heating element. What happens is when the fridge senses it has a buildup of frost on the cooling coils, it shuts off the compressor and turns on the heating element to defrost them. What happened (and it turned out was a problem common to that model) was the sensor switch on the cooling coils went bad, and was commanding the defrost cycle. I was able to find a new sensor/switch online for about $15. Put it in and that fridge is still running fine 5 years later.

 

[ajwillys]

I have no idea if its frost free. It's a True commercial beer refrigerator. It's an older model of the TDD-3 which is on their website.

I have a few automotive fittings but I haven't tried to fit them yet. Once I took both sides off and realized it looked like a valve there, I decided to think about it a bit more first.

Also, the back of the valve has a pipe that runs inside the compressor.

 

[ajwillys]

You guys are not going to believe this.... I was sitting there staring at the compressor with it plugged in and just happened to notice that way back hidden there was a fan tucked in between the coils and the compressor. It wasn't spinning so I thought maybe it was overheating because of it. I grabbed a clip on fan and pointed it towards the coils through the compressor and turned the fridge on. It never turned off again. That thing ran all the way down to 25 degrees (it was 65 outside) before I finally unplugged it. Needless to say I was pretty excited and figured just the fan was broke. After finagling for a bit, I got the whole assembly slid out (man this commercial stuff is nice) and noticed that the fan blade was stuck on something in there! I cleared it out and plugged it in. The fan started right up and again never quit. This fridge gets super cold and runs like a champ! I'm stoked about this now! Especially since I only paid $75 and it can hold like 12 cornies or 4 or so fermenters.

 

[jwatkins56550]

Nice job fixing that! I have a true commercial fridge and it was giving me similar problems, although mine I found out has a pinhole leak in the freon line. I still need to get that fixed....But it worked well when I got more freon in it, just leaked out again!

 

[KCBrewer]

That's great. It's always nice when the fix is free! And that's a steal of a price, all because something got stuck in the fan. lol