True Beer Cooler

[andrewd33]

I do HVAC not refrigeration, but do some maintenance on the refrigeration and ice machine in my fathers bar. I have a True Beer Cooler that I had a compressor replaced on about 2 years ago. The cooler was not getting that cold. I blasted condenser with nitrogen and unit went on and got cold, but next day noticed compresor short cycling. I didn't want to leave on until I determined what was causing this. I do know that when condenser was dirty the compressor cycled off on thermal overload. Upon further looking I noticed that although coil appeared clean that the actual refrig tubing crossing through the fins had been insulated with dust that didn't come off with nitrogen blast. I worked on cleaning the coil for about an hour and 1/2 and finally alki foamed the condenser and used garden hose on high pressure to rinse clean. Coil now immaculate, restarted unit up and compressor starts to short cycle. Condenser air is not that warm but compressor is hot and shutting off on thermal overload, evap was cold. Is it possible that there is a blockage that is preventing the refrigerant to pass into the condenser and forcing compressor to shut off. I am not about to replace another compressor, if that is the case I will replace the entire cooler. I am going to ask service mgr at my co some advice, but we are HVAC not refrig. Any Ideas. I didn't open system up or apply gauges.

[jeffcolledge]

Try allowing the compressor to cool off for a day or so by shutting the cooler off completely. This should solve the problem. If it doesn't, you'll likely need to replace it, again...couple of questions though...
Is it a Tecumseh AEA4440YXA?
Is the condenser section on the lower right corner, and if so, is there enough room for the discharge air off the condenser to circulate? The reason I ask is, I had a problem like this once and I was on the second compressor in as many years. It was on it's last leg too. I told the customer if I was to replace the compressor again, the entire condenser is going in a remote location. Well I ended up replacing it, locating it downstairs (where there is lots of room for it to breathe) and it has worked, problem free for 2 years.

[hvac3901]

out of curiosity what do you call short cycling? what is the method of temp. control? could it be suction pressure control and short on gas? i would also check the pressures.

[andrewd33]

I was just down their and started it up and let it run for a few minutes and it seemed to work, the evaporator felt like it was starting to get cold, but I shut off after about five minutes, didn't want to seize compressor before hearing some advice. The compressor fired right up when I started it and didn't hesitate or even sound like it had to try like some failing compressors. I will let it rip tommorow and see how it goes from there. What you mentioned about locating the comp in a remote location is a good Idea, I thought about that too. I have a basement that is below it and would consider replacing the entire condenser and locating downstairs. How would you size the condenser for this box. I am assuming to match compressor that is there with a complete remote refrig condensing unit and piping into exisiting lines dropping down on right hand side of cooler. Yes condenser is on the right hand side and I think new compressor is a copeland, but will check tommorow. IF I have to replace entire condensing unit and locate in remote location is are their any other rules to this type of change out that are different than a/c condenser change out. Usually on a condensing unit changeout on a a/c if burnout I put suction and liquid line filters and then change about a week to 10 days later. Is this the same for refrig?

These units are poorly designed as far as I am concerned. The reason the first compr burned out was dirty condenser. It looked clean to me, I thought it was clean but when you are on the floor trying to see if the coil is clean and you see all the fins clear through , looked good to me. This time I looked and looked and saw the dirt was actually wrapped around the horizontal coil, not the fins and as much as I blasted I guess the nicotene and everthing else ganged up and made the coils going through the fins like a blanket of insulation not allowing the heat to even pass into the fins. Anyhow Just venting on the poor design. If I was smart I would build a custom case and shelve it to my needs and put an evaporator inside with a remote condenser, but time isnt' avail.

Thanks again.

[jeffcolledge]

If it's a tecumseh unit, than they made a condenser that was specifically sized and designed for true coolers. If you were to replace the entire condensing unit, bought from a wholesaler, it would come with a receiver which you don't need as your system is a cap tube controlled by a immersion type coil temp. sensing thermostat. (If any of this is in-accurate, let me know). In my case, I re-located the unit downstairs with the new compressor and replaced the cap tube. Then I blew out the system internally with nitroogen to remove any debris. I installed a liquid line drier and treated and power washed the condenser coil. I don't think it's necessary to use a suc. drier, but you could if you feel it's necessary.

[mikep]

I think I know your problem. When the compressor was replaced, they used a refrigerant called Hot Shot.
Hot Shot will cause a compressor to really run hot and if the charge is off (fractionated)due to a small leak, you will cycle on the overload protector. Had a similar prob on a Traulsen.

[andrewd33]

I put gauges on the machine and it did need some Refrigerant. This is a R-134 A machine and was before the Compressor was replaced. I don't think there is hot shot in it. I am not a refrigeration genious though. Anyhow the service mgr in my company got me a tank of 134 A since we only use 22 and 410 and I did add a bit to adjust to 35 degree coil temp, can't remember the exact pressures off hand. Anyhow the unit starts up the evap gets cold and the condenser gets hot and stays on for a good five minutes and then shuts off. Compressor doesn't have a difficult time starting the first time. Shortly after the compressor cycles off it tries to start again about two times and then fires up again for about 1 minute and shuts off. I called my service mgr and he said the charge was fine and not to add any more. He seems to think that there may be a problem with a low pressure cut off or high pressure cut of switch. I didn't see a ranco or similiar type control, but he said there is definintely some type of control that is causing this to shut off. Just to clarify this cycling is happening after starting up the box when it is warm inside so it couldn't be possible that the tstat is cutting it out. Is it possible that a liquid line dryer filter is clogged and not allowing enough of the liquid to pass through the cycle or is it time to throw in the towel and buy a new cooler? I don't really want to buy another compressor or condensing unit for this unit since the doors on the top are all banged up from bartenders sitting on and the inside is beat up. If I can get it running again I would be happy

[jeffcolledge]

I believe it is the stat. It should be immersed in a well in the evap. On the side of the coil is where you will find the setting, make sure it is a the coldest setting, if it is, try replacing it. There is no low pressure switch on these units. Is the condenser fan motor shutting off with the compressor, or is it just the compressor? If its both, its the stat, if its just the compressor, then you have other problems...what are the pressures and temps?

[andrewd33]

Compressor only is shutting off. I will take the readings again tommorow. Compressor runs for about 5 minutes then shuts off condenser fan remains on. I didn't think there was a pressure control on this but my service mgr said there had to be, although he didn't see the unit he was helping me troubleshoot on symptoms alone. When you say other problems, do you mean fatal problems with compressor? If this compressor is fried I think I will trash the entire unit and get a new one before I go and spend any more money on a third compressor. I would actually like to find out about custom refrig cabinets that I can mount evaps in and locate comps in basement. I am planning to redo the bar and would like to have built in refrig, but don't know how to find the cabinets. would be nice If I could patch this thing to get me through the summer though.

[condenseddave]

If the unit is correctly wired, the overload is tripping.

[condenseddave]

And if the compressor is bad, don't go throwing a new condensing unit at it until you find out what is killing the compressors.

[andrewd33]

Condenser is clean now, the refrigerant is at ideal charge, there is no pressure cut off for low or high pressure as you said. If the unit is tripping on overload could it be a blockage not allowing the hot gas to pass into the condenser, causing the compressor to cycle off. Does it sound like the compressor is tired and doing this as its swan song or is there something I am missing. Believe me I decided not to put another compressor or condenser into this unit as it is beat up as it is and I don't want to throw any more substantial amount of $ into it. If it is something like a blocked filter dryer or a short then I will fix, if not I will trash it and try to hold off till I redo the bar and can put in built in boxes with remote condensers.

[R12rules]

If the unit is going off after five minutes, and power is yet available at the terminals, then you will want tohave gages mounted and an amp meter around one leg of the motor compressor as well as a volt meter monitoring the incoming power to the unit ... before as well as during the period the unit trips off.

Then you want to quickly trace down WHERE the circuit if opening up at.
Someone said the overload is opening up. You will want to monitor that.

Heck, while your at it, why not attach a temp meter to the suction line, about a foot from the unit and see what it's reading as the system is in operation.


If it's too cold ... then your getting floodback. No bueno.
If it's too hot... then your starving the evaporator and the whole system is operating way under it's ideal capacity.

Have your local supply house get you a compressor curve for this particular unit.
This paper will be printed with the specs on what this unit will draw for current at what suction adn head pressures and during what ambient and load conditions.

If this compressor is dying .... cut it open and see what happended inside. Just for the education of it.

[mikep]

Is this unit on an extension cord or 16 gauge power wire. That will cause it to kick out on overload.

[andrewd33]

I am glad we have enough backup refrigeration that I could drag my feet on getting this up and running. But Kids are home from college and BT's don't like having to run to walk in basement to restock beer on busy nights. Anyhow the service mgr in the co I work for made it out and hooked up gauges and amp meter, as he predicted the compressor is dying. Drawing high amps. We ordered a new compressor from supply house and we (he) will change for me, but I will learn how to so next time I need to replace a refrig compressor I won't have to bother him. Anyhow I already know why this compressor died, the coil was plugged as all hell and I thought it was clean but it really wasn't and it killed it. I may just open this can up and look inside to see what exactly happened. I don't like the smell of 134 A. Smell reminds me of something or someone unclean!!! Anyhow It should be up and running by the next weekend.

[len]

you are gonna open that can up?with what? hack saw 3hrs,at best,those cans are welded,they are not semis,good luck ,just junk it forget why it cooked you already answered that ?

[basser]

Reread r12's post. To know that the compressor is drawing high amps you MUST have the compressor curve sheet. (You still haven't stated the pressures.) You can have a high suction and/or high head pressures and this will result in a higher amp draw but not an improper amp draw. Changing the compressor here would not help anything.

Assumimg that this compressor is indeed done change it and open the compressor if you can. You need to verify why it failed or you will fail another one. If you overheated it because of the condenser problem then the oil will be very dark. Pour the oil out the suction line and look at the color, (should look like new oil). If you do open the compressor remove the head and look at the valve plate.

If you go this far, I'm interested in what you see and can offer some guidance.