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Thread: Old McCall refrigerator
09-18-2012, 08:43 PM #1
Old McCall refrigerator
I'm trying to get correct cap tube size on this r-12 upright. Delfield said model number doesn't exist when i called!!! Here's a pic of the data plate. Can anyone help. Unit could have had a dual feed originally or even a txv w/ receiver.I don't know!!! It looks like Model# 6045 to me and Serial # M-21512.
09-18-2012, 10:06 PM #2
supcoAire Serv of SW Connecticut- Gas heat, dual fuel and central a/c systems installed and serviced
09-19-2012, 12:50 AM #3
Yeah, i did that already cut 78" of bc2 and got 13 oz of mp39 in it before i had to stop. Data plate says 32oz! WTF!!!!! Did this thing have a receiver originally?
09-19-2012, 07:52 AM #4
09-19-2012, 08:32 AM #5Professional Member
- Join Date
- Jun 2003
why did you have to stop?
Was this a tecumseh AEA4440AXA? If so, you need to use the HIGH TEMP column of the Supco chart. You should have around 36" BC 2 and i usually chop it down to 28-30" if I can't attach it to the suction line for heat exchange.
09-19-2012, 10:44 AM #6
It's an ARE37C3-IAA-901
I stopped because pressure looked like they were supposed too. Ambient 100° High side 240 lo 30. Low dropped to around 25 before i left. Box temp at 42°. Liquid line was 116°.
Due to the High ambients. I want to put it back to factory and charge w/ r-12. It's in a snack bar at a outdoor amphitheater. Get's used maybe twice a month. I fixed their walk in and guy asked me to look at this upright. I made him no promises due to no A/c in building!! Can i get it to work?
09-20-2012, 06:03 AM #7
That liqiud line temp looks way to high. Might try jb industries cap tube sizing chart. I never had good luck with such a short tube.
09-20-2012, 08:39 AM #8
Check out Tecumseh's cap tube selection application written by Andy Schoen: Tecumseh Capillary Tube Sizing
I've used it many times with much better results than any of the old charts.
09-20-2012, 10:50 AM #9
09-20-2012, 12:03 PM #10
To use it, you have a choice of either selecting a Tecumseh compressor from the dropdown list or enter a capacity at the conditions you enter.
You can use the Tecumseh Competitive Cross Reference program to find an equivalent Tecumseh compressor, which in this case would be an AEA4440YXA, and select that. Or you could simply look up the Copeland compressor's capacity on the Emerson website.
For the Tube ID, you can either let the program Auto-Select the ID of cap tube for you or you can specify an ID from the dropdown list. If you specify an ID, you need to check what the resulting length is and try to stay with about 5 ft as a minimum and 12 ft as a maximum length and adjust the ID accordingly.
For the operating conditions, it varies with the type of system you have and its manufacturer, but in general you can use +20ºF SST and 120ºF SCT for a typical reach-in cooler. That's based on an assumption of 20ºF below box temp and 30ºF above ambient. It'll get you pretty close.
You also want to pay attention to the part about heat exchange length. This refers to the length of cap tube which is going to be attached to the suction line to act as a heat exchanger. It make a significant difference in the length of cap tube required.
The default heat exchange length of 36" is fairly typical on most systems. Due to limitations built into the program, the minimum heat exchange length is set to 6", so if you're not attaching the cap to the suction, use 6" anyway.
09-20-2012, 08:51 PM #11
Thanks Icemeister. Seems like i'm way too long at 78" compared to the Tecumshe calc. Why wouldn't they be the same?? Maybe i'll go back and cut 30" off!!
09-20-2012, 09:43 PM #12
If you were to compare all of the available cap tube sizing information, (which isn't much) you'd find right off the bat that none of it agrees.
Likely the most popular chart out there is Supco's. I used it for longer than I care to remember and it worked OK for the most part. Their chart was created back in the 1960's, primarily by trial and error...and extrapolation. I have high regards for Henry Ahrens for his work back then and I'm sure he'd be thrilled to see what we now have to work with.
This new Tecumseh program reflects the results a lot of new studies about how cap tubes actually work and how they can be modeled using computers. There have been a few cap tube programs floating about in the last ten years or so, but this is the first one to use the latest info. I've had very good results in the field using it.
09-20-2012, 09:25 PM #13Professional Member
- Join Date
- Jul 2011
- Lehigh Valley, PA
Is this a large unit with the evaporator on lefthand vertical wall, condensing unit on top? Could it be a converted pizza retarder? I've seen a few old R12 McCall pizza retarders. They all have TXV's. I just recently replaced the TXV in one, it's working very good using a pressure control switch for temperature control and R409A.