General quarters !!! The beer cooler has died

[JWPATE]

For several weeks now the beer cooler has gone from bad to worse. First I just noticed that it was running non-stop. I keep it in a closet-sized little room, and every time I went in the compressor was running. As it turned out I had a technician over on another matter and ask whether he could check the freon charge on the beer cooler. He and his associate pulled it out and took the back panel off & hooked up a gauge hose. I was not watching what they did, but from the other room I heard one say "It's at about five, what do you think". The other replied "oh, give it about fifteen".

Then, over the next week or so I noticed the beer started excessive foaming and spitting. First I wondered about the CO pressure and the gauge did show several times the usual pressure, so I turned off the valve. I was expecting the pressure to work off over the next few days as the beer was drawn down, but instead, the tap continued to spit and foam, and seemed worse each day. FINALLY, the light went off in my head and I decided to check the box temperature. Sure enough it was up in the high 60's and the pressure rise now made sense.

The compressor was still running 24/7 but now it is cooling nothing. I lost confidence in the afore-mentioned pair of technicians, and decided to get to know this beer cooler better myself. It is a TRUE cooler I have had since buying it used back in 1989. This is the first time it has failed to keep the beer kegs cold. I look inside the door and find that the model number is TDD-1, and it is serial number 539441.

So, with it still running, I pull off the rear access panel and begin to peer around inside the compressor unit. I feel with my finger tips for relative temperatures and find that the discharge line is only slightly warm. The compressor itself is hot to the touch, not surprising I suppose for it is running non-stop and the return suction line is at about ambient temperature, as is the evaporator coil. The only cool line is that leaving the condenser and it is cold enough that the drier is cool and the first few inches of the capillary tube is damp with condensation.

Well, I am not thinking the charge is low because it was just serviced a week ago, and hasn't leaked in all those many years before. But I wonder if the compressor is anywhere near its rated run amps., which the sticker inside the door lists as 3.4 amps. I get out the amp gauge and find that it is only drawing less than half that amount.

So, I decide that I will have a go at this cooler myself. As I see it, the compressor is not compressing much, even though the motor in it is running fine. Perhaps the valves inside have finally failed. Are they made of reeds? Anyway, it is unplugged now, and out of service for the first time since 1989.

Time to start getting up to speed on what parts are still available for this old R12 unit.

I will let you know what I find.

[THE ICEMAN]

There are a couple of possibilities... You have a restriction in the system - the drier or capillary tube - or there is a leak in the system. Most likely a leak.
If the freon leaked out & the system started to act up after only a week, there is probably a good sized leak. Did the repairmen bother to look for a leak in the system? What the repairmen should have done, failing to find a leak, was to remove the existing charge, evacuate the system & weigh in the proper amount of freon. That takes any guesswork out of the mix.
If the repairmen are worth anything, they will come back & actually fix the problem without any additional charge, provided it is a simple matter of repairing a leak. If there are parts involved, such as a new evaporator coil etc. then an additional charge would be justified. Still, they should have done more than just guess on recharging the system. You may want to find some other company to look at it. Make sure they are actually experienced working on those types of systems. A simple A/C repairman won't cut it.


THE ICEMAN

[JWPATE]

THANKS for that thoughtful response Mr. Iceman, and I believe your diagnosis is right on the money. I should explain that my opening post above is about a week old now. When I first joined this excellent site I was unable to post for a few days while my membership was confirmed. I have gone further along now, and the TRUE cooler is actually now apart, as I will explain.

I should explain also that while you will already have correctly concluded I am inexperienced in refrigeration matters, I none-the-less am EPA certified Section 608 universal and Section 609. This was necessary so as to continue servicing the A/C systems on my own home and autos, I have never looked into a refrigeration unit of any kind.

Now back to the TRUE cooler. I was unable to detect a leak! After deciding that the cooler was going to receive a general overhaul, I first recovered the freon and then charged the system with 200 pounds of nitrogen. After four days the gauge was still showing 200. So I was still focused on the compressor, and thinking that after 25 years of faithful service it was probably due for honorable retirement anyway.

So I made a call to the replacement parts desk at TRUE. The serial number was looked up, revealing that the unit was built in 1987, two years before I came into possession. The company no longer supports R12 boxes, as might be expected, but is able to supply all the old parts numbers. In the case of the compressor though, none of the old ones are left, and no substitute number is available from TRUE.

So next I take a closer look at the existing compressor. First I find to my surprise, that it appears to have been already replaced during the two years before I bought the unit. There is strong evidence in the form of many non-factory-looking solder joints on the lines, and the service port looks to have been added also. Regardless, the compressor is an ASPERA A5144A. I found online a TECUMSEH cross over chart listing that compressor, and suggesting the TECUMSEH AEA3417AXA as a replacement. Both are thermally protected 1/5 HP, R12 units. I was able to locate the TECUMSEH part number at one of our local parts suppliers and so went over for a look. The size was practically identical so I brought it home.

I found the drier on one of the online stores and ordered two.

[THE ICEMAN]

Before you condemn the compressor... What pressures were you running? If you had your gauges on the suction side while the compressor was not running your static pressure would have been somewhere around 70 to 80 psi. When you start up the compressor the the pressure should drop into the 20 to 25 psi range with a warm box & a full charge. If the pressure did drop, the compressor is working & the valves are fine. If the pressure hardly moves then the valves are bad.


THE ICEMAN

[JWPATE]

Yes, I suppose the compressor was too quickly blamed for the failure. I had about the static pressure you suggest all right, and knowing that the compressor was only running at less than half its rated amps, I just concluded it had failed. No going back now, but if there is a next time I will surely remember your advise.

As it is, after thinking over your first suggestion about blockage/restriction, it does seem reasonable to me that it would be foolish to put in a new compressor without changing the capillary tube. I did think of that earlier, and called the TRUE parts desk about the part number for a new line set. They do have the part number, but the agent was concerned when he also noted 134a on the listing. I was also concerned, and decided not to order and just see how the old lines do. But now I have determined to change out the lines, but not with the 143a part. Rather, I made an attempt to determine the cap ID already, using the nearest wire gauge drill bits I have. The .031 bit fit in too loosely I thought, and the .037 bit would not go in, though I thought it was very close. I am guessing that the original cap line is .036.

So today I have been at it again to see how long the original cap line is. First, in order to get the evap. coil removed it is better to start with the door and top of the cooler removed.
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Then it is possible to pull out the evap. coil complete with the cap tube and suction line. It's tight in the little space they occupy, but they did pull out without too much effort.
Here is the cooler without its door and top panel, and before I forgot to do so I used this opportunity to replace that evaporator drain tube. It turned out that I had a length of clear vinyl tube in 1/2 ID and 5/8 OD which seems a direct replacement, and my old drain tube did have a leak.

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So now, with the line set out in the open I can see that the factory had the cap tube and suction line joined together with tape in about four places. I expected to find them wrapped completely in insulation tape, but now realize there isn't room for that in the small compartment they run through.

It is also a surprise to find the length of the cap tube. From looking over a JB Cap Tube Chart on the net, I had rather expected the tube to be .036 and 8 feet or so. Actually it measured out at 11 1/2 feet after allowing a couple of inches for both my drier cut and the one before me.

I have 12 feet of the tube in order now along with a gauge to confirm the old tube ID.

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So now I am dead in the water for a while, so cleaned up the box as well as I could and checked out the compressor and evap. fans. Actually it turns out that they are identical fans and motors. Only the mounting brackets are different, the compressor being a little taller. In spite of their age both are still doing fine, and I shall plan to reuse them.

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[JWPATE]

Here is a look at the condenser tray as it was on the way out. Up until now, I had never done anything to this system, except blow out those condenser fins every now and then.

I suppose it could be the original compressor, but I just don't know the answer.

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And the little driers came in the mail today, so I went ahead and built up the condenser unit using the new TECUMSEH compressor. It fit right into the original mounting-bolt holes.

I replaced all the old lines and left plenty of length on that new suction line because I am wondering about providing a loop in it so that the tray can be pulled out rearward in future condenser fin cleaning exercises. We shall see, there certainly a lot of extra room.

I will not start on the condenser yet, as the cap tube replacement just went into shipment today. Since it will be maybe a week setting like this, I closed the end of that suction line with solder, pulled a quick vacuum on the unit, and then charged it with 200 pounds of nitrogen. Most of the pressure will leak past that drier cover where the cap tube orifice is still open. Should keep the drier in new condition though. I did blow out the condenser with nitrogen also before mounting it, and the mineral oil which came out seemed clean and clear.

I notice that the new compressor is filled with AB oil, which I have been led to understand is a synthetic, ALKYL BENZENE, now being used as a replacement for mineral oil in R12 systems such as this one. I believe it has somewhat better thermal stability, but am only hopeful on the issue of whether it is hydroscopic. I certainly hope not, and have read no complaints regarding AB oil.

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[THE ICEMAN]

By the time you're done you will almost have a brand new unit. From the looks of the pic you provided I would say that is the original compressor. The tin data plate gives it away.

All refrigerant oils are hygroscopic to some degree but AB oil is fairly safe in that regard. The worst is the new POE (polyolester) oil used with R134A, R404a etc. Make sure you pull a good vacuum on the system before charging. If you don't have any R12 there are options for replacement refrigerants. The least expensive would probably be Hot Shot 2 or R417C. It's fairly easy to use if you decide to go that direction. The biggest thing to remember is that it uses 80% of an R12 charge. Here's a video that provides some guidelines... https://www.youtube.com/watch?v=BGBqJuMAmO4#t


THE ICEMAN

[JWPATE]

Thanks for clearing things up Iceman and that confirms that this compressor has served non-stop for 27 years. Not bad. Ah, the metal data plate was a clue I would never have known about, and your comments on AB oil are comforting too. Yes, I was aware of the great care which must be taken with POE oil.

I will stick with R12 when it comes time to charge it. Thankfully it only takes 9 ounces, and I have a fair supply on hand for the old cars here.

[JWPATE]

Further to the possibility of blockage having been the problem, it seemed worthwhile to have a look inside the old drier. Here we see that the thing is packed full of BB size spheres of desiccant, which now are amber from 27 years exposure to the freon/oil mix. Perhaps they started life white, or at least a lighter shade. Don't know that answer for these are the first I have seen.

There is no evidence though of any kind of wax or other undesirables. I have read that when capillary tubes suffer from blockage problems, it most often can be found in the first inch or so of the tube. That is the little section of tube on upper right, and it is clear/open.

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The drier inlet end is fitted with a course filter plate, seen here in the upper section of the photo. I was easily able to stick a 0.024 drill bit through those holes, so they are on the order of about twenty-thousands inch. That is still smaller though than the cap tube ID. And at the outlet end of the drier is a fine screen filter, as seen in the lower section. Both filter screens were clean and free of anything I could detect, so I believe we can rule out the drier having been a cause factor.

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[THE ICEMAN]

Once you are ready to charge things up you need to be careful if you are not familiar with cap tube systems, they can be finicky. Let me know if you have questions about it.
I will be going camping this weekend so don't be disappointed if I don't respond right away.


THE ICEMAN

[JWPATE]

I very much appreciate your assistance Iceman, and will not hesitate in asking for more of it. I too am going to busy on other things for the next five days or so, and by then I should have the new cap tube.

Enjoy the camping!

[JWPATE]

The new length of capillary tube arrived yesterday afternoon and so I can start now to put things back together. With the set of ID testing rods it is now confirmed that the original tube was 0.036 inch ID.

So I shall start at the evaporator end of the system, I could not resist the temptation to run the cap tube inside the suction line in hopes of a better heat exchange. I didn't see any advantage in replacing the little accumulator, and therefore I just unsoldered the cap tube and suction line. Those two are new now and here is the method used to enter and exit the suction line with the cap tube. All this is in place now, and tomorrow I will get on with the lower end.

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[JWPATE]

So the compressor tray went back to its home today, allowing me to complete the cap tube and suction line hookups along the same line used up in the evaporator yesterday. Eventually, the suction line will be wrapped in insulation tape like the original was. For now though I want to leave it bare in order to easily read the temperatures when adding freon.

For now, I have a charge of nitrogen in there and will wait a day or two watching whether that 150 pound gauge reading holds.

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[JWPATE]

The pressure is unchanged from yesterday so I suppose we are good to go ahead and close the unit up.
One more thing of interest to me was the temperature controller. I have read that many owners have traced cooling problems to the controller, so it seemed this would be a convenient time to renew it. The old one is out anyway.

It must be understood that the temp. controller is not reacting to the inside box temperature, at least not directly. Instead, the sensor tube runs inside a copper tube, which itself is wired up to the front side of the condenser coil. That copper tube is closed at one end so as to keep water out. After slipping the sensor line inside and all the way across, the open end should also be closed using a sealing compound as seen below. Best not use silicone or anything else which will set up, for someday it will surely need changing again. It can be done with the top and door still on the cooler, but is much easier as seen here.

That pointer on the right side illustrates that the copper tube runs about 80% of the way across the condenser coil.

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The part number I obtained from TRUE was 800393 as seen below. This is for my serial number unit, which is from 1987. Newer units running on 134a refrigerant use a different part number. From searching around through TRUE service manuals online, I found that the above part number is supposed to open contact at 19.5 F, and close contact at 40 F. That is interesting data, roughly a twenty degree spread between 20-40 degrees. So I strapped a temp probe to the sensor coil and alligator clips to the electrical connectors and stuck the thing in my freezer this morning. With the door closed against the elect and temp leads, I stood watching the gauges for the open, and then pulled everything back out and continued watching for the close.

Of course, this is a VERY approximate way of testing since the changes are far more rapid than would occur in actual operation. None-the-less I at least wanted to confirm that the controller was somewhere in-the-ballpark - and it was. I got opening at 23 degrees and closing at 40 degrees.

I also tested the old controller the same way and was getting good operation still with it, but at about five degrees higher on both opening and closing. I put the new temp controller in place inside the cooler.

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I just took this shot in case some other member is interested. This is looking down at the left, rear corner of the cooler with the top removed. The suction line runs down here in a channel through the insulation. Normally the cap tube would also be visible, but mine is now inside the suction line. Two electrical circuits run up through the same channel - a parallel circuit to the evap. fan, and a series circuit to the temp controller.

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So with all the functional components finished it is time to put the wheels back on along with the top and door.

Looks like my old friend again now, and that's enough for me today. Tomorrow I shall most likely release the nitrogen charge, pull a vacuum and recharge the freon.

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[djc]

The True is nice, but what's the car?