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Capillary Tube

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#41 ·
ascj said:
I jumped it out.....because the fan wasn't kicking on. I checked it by blowing some liquid on to it and it did close. But left it jumped out as I was checking it.

I was a little hesitant about adding gas, since I was at 11 oz and the plate was 8oz. Would a couple oz really drop my sh that much? I was at like 95+ degrees SH.
Click to expand...
Take that jumper off the fans and let the evap get cold you got an 80 degree box blowing hot air over the coil. Chances are the pump is going to get really hot and could trip the ol.

And SH doesn't really mean much at that kind of temp in the box you need to check it when your closer to opperating temps... I know you can't there but try taking that jumper off the klixon and see what happens at least your compressor will be alot cooler.
 
#43 ·
ascj said:
I did add 3 more oz to see what would happen. Not much change. It just won't run long enough with a such a high suction to the compressor.
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You could try false loading the box with some cold or frozed product. It might let tsystem get on down. Then take out the stuff you put in the box and replace it with cold product you are going to keep in the box. This is a long shot, and it probably won't work. And if it does, you still have a problem. It sounds to me that head pressure is still low for that load. You might even have a bad overload.
 
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#45 ·
A hot pull down with a cap tube will look like an undercharged system as far as superheat goes. You will only be able to get a true assesment of charge when the unit pulls down to temp. I agree that the head pressure looks low for that ambient temperature espcially with that much load on the evaporator. I have a feeling that you either have a faulty overload, or a compressor that has some fatal mechanical damage.
 
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Discussion starter · #46 ·
A few questions I have. Don't have much experience with cap tubes. Would the suction be that low with such a high load on the evap? I'm thinking that that it could be because the cap tube is just a pressure drop. But on the other hand you would thing that the suction temp would drop pretty quick, with no product in the box. Btw......I did run it for 45 minutes with the coil stat hooked up, keeping the evap fan off. Before I jumped it out.

Also the compressor is definitely overheating. (I should have taken the shell and discharge temp....but it was hot as hell) Why wouldn't it with a 73 degree return?

I also threw 2 bags off ice in there, to try to get the temp down to see what would happen. But it didn't drop the temp much......maybe 5 degrees or so.

The way I evacuated and charge was.......I pulled a 200 micron vacuum through my gauges (didn't take long with such a small system). Both lines I had ball valves at the ports. I then hooked my tank up and bleed liquid up to the ball valves. I zeroed my scale that reads oz to the hundredth. I charged 8.13oz of 404a. I did add another 3.12 oz of 404a later to see what would happen.
 
#47 ·
ascj A question I have is how are you going to fix a cap tube system that is a freezer and with the same components be a cooler?
IMO if it is for a friend you should have them pick what they want the most and go from there other wise it will run piss poor no matter what you do to it :.02:
 
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#49 ·
low suction pressure and high superheat really sounds like a restriction huh. i always try to order oem capillary tubes. i honestly would rather work on a walk in box any day rather than a reach in cooler or freezer. theres nothin worse than changing out a cap tube and still haveing an issue.
 
#50 ·
I would agree with it being restricted. I use a IR gun to measure the temperature of the coils in the condenser, if the top coil is warm but the rest are cool and maybe even the last will be nearly ambient then you have a restriction.

could be the filter, could be the cap tube.

jim
 
#51 ·
I have been seeing alot of cap tube systems and heard about adding supco s8 additive oil to system and it will help unclogg cap tube. My question is how do you add the oil to the system.
 
#52 ·
Google this

CPSTLJ2

I dont know if supco will clean clogged caps , it may make it worse because it loosens debris wherever its found.

Its basically kerosene

Your best bet is to replace drier , and cut out 5 inches of cap tube because thats usually where they clog

Cut drier open to see what the problem was..... Wax build up , or drier self destructed internally

If it was wax , then you need to keep cond coil clean because its getting too hot
 
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#53 ·
ascj said:
So I check it out. First I check the coils and notice a wiring mess behind the evap panel. So I clean it all up. I fire it up. It runs a 190 head, but suction drops down to 7psi. Then it slowly climbs and compressor shuts down on internal overload. I think it's a clogged cap tube.
Click to expand...
Slowly climbs? You should have felt around a little. Was the condenser at ambient temp over most of it's surface?

I think you have a bad compressor.

It takes some experience to consistently properly diagnose the differences between cap restriction, inefficient compressor, and low charge. Some companies make it a habit that anytime they find a cap tube restriction (or what they think is a cap tube restriction), they change the cap tube, compressor, and drier. This will solve the problem since they have addressed everything, including a possible short charge.

Oh, and there is a way to size a cap tube on the fly with the system open. Read the last two pages: http://www.supco.com/images/pdfs/Manuals-Instructions/Cap Tubing Manual.pdf
 
#54 ·
Snapperhead said:
Google this

CPSTLJ2

I dont know if supco will clean clogged caps , it may make it worse because it loosens debris wherever its found.

Its basically kerosene

Your best bet is to replace drier , and cut out 5 inches of cap tube because thats usually where they clog

Cut drier open to see what the problem was..... Wax build up , or drier self destructed internally

If it was wax , then you need to keep cond coil clean because its getting too hot
Click to expand...
Thankyou for the advise. Very helpful.
 
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