View Full Version : reach in refrigeration boxes
in reach in boxes were the condensor is sitting on the bottom the suction pipe is coiled up so u can slide unit out for service with out bending the line. my question is can that be shortend by removing coile line a replacing it with a straight run from compressor to evap or does the coiled suction line serve as an oil trap ? im working doing overhauls on used restaurant eqiup. would love feed back from others in the appliance biz. thx
intellitech
11-27-2008, 08:00 PM
You pose an interesting question....in my experience though with the type of reach-ins you're talking about is that those refrigerant lines are coiled for the very purpose of pulling the condensing unit out for service. If you hard pipe/straight run the line set then how do you plan to service the condensing unit? Imagine trying to change a compressor without pulling the condensing unit out......I am sure you get my point.
Burnerfixer
11-27-2008, 08:43 PM
As drilling a hole in the bottom of a boat to let the water out. :eek:
A1 Burt
11-27-2008, 09:22 PM
the coiled line serves many purpes's it let's you pull the conden's unit out
it act's as a vibration lupe hear is a way too make those loop's take some think round get soft coper tape or tie one end too round thing now roll coper around as many time's as you like & bingo there you go just like from the factory
I think that you are working on these in a shop & up on a bench much easyer then on the job where you are lucky to get acess to the front of box
thx for the input only reason i asked was that particular unit came from south america and had been changed from factory specs it also had a nice convient side access panel were everything was reachable i changed the compressor back to what it was supposed to be.
That nice side access will probably be blocked by some without wheels after you sell it. Let it come out the front, just in case.
Bet that box is a deli box.
I have worked on ToRey deli boxes. The CU does not slide out the front. It only comes out the side. It has coiled pipe to get it out the front. What a POS.
yes it is a deli case i removed the coiled copper and repiped it in, its dual evap natual convection a 134a system. question with a wieghed in charge seems to cool good two different compartments upper (display area) and lower wich seems to stay 10 degrees colder than the upper what sh am i looking at ? at a temp of 38 in display case i had 35 sh. I also wonder now as im typing this if removing that coiuled suction loop, is liqiud refrigerant going to migrate to the compressor since the evaps are above the unit ? i let the suction come down just a little below the compressorand made my bends back up the compressor. appreciate your feed back.
Burnerfixer
11-30-2008, 09:27 AM
yes it is a deli case i removed the coiled copper and re-piped it in, its dual evap natural convection a 134a system. question with a weighed in charge seems to cool good two different compartments upper (display area) and lower which seems to stay 10 degrees colder than the upper what sh am i looking at ? at a temp of 38 in display case i had 35 sh. I also wonder now as I'm typing this if removing that coiled suction loop, is liquid refrigerant going to migrate to the compressor since the evaps are above the unit ? i let the suction come down just a little below the compressor and made my bends back up the compressor. appreciate your feed back.
:) Why not use an EPR valve on the lower coil and set it to a pressure corresponding to the coil temperature you would like to maintain ?
im not familiar with an epr valve but would like to hear more about it. the way it is now is evrything piped together, one thermostat the bottom is a insulated none visible box as the top is totaly visible
absoair
11-30-2008, 07:10 PM
you stated you weighed the charge-wouldn't the charge change with the removal of the loop,is this a cap tube system? it appears to simplify things is to install the loop as original. or as close as possible to original.
Suction line will not matter on the charge, but the liquid line would be about 1/3 oz per foot.
The under cabinet is supposed to be a light freezer. Many of them have electric defrost.
Those gravity evaps take lots of gas too. Best judge the charge by SH after the box has pulled down.
Burnerfixer
12-02-2008, 05:52 AM
Suction line will not matter on the charge, but the liquid line would be about 1/3 oz per foot.
The under cabinet is supposed to be a light freezer. Many of them have electric defrost.
Those gravity evaps take lots of gas too. Best judge the charge by SH after the box has pulled down.
The under cabinet is supposed to be a light freezer. Many of them have electric defrost. :eek::eek: He has a double duty case. Display on top with storage on the bottom. :confused: Why would he want a light freezer ?
We have had this problem and aleviataed it using an EPR valve on the lower coil.
I may not know as much as my cousin, but this is a standard fix.
Maybe "Andy Schoen" would like to comment on this/
well they were not the owners were not interested in having me install a epr for the lower box, i adjusted thermostat to hold the display case on top at 35 and the lower none visible box was at 27 they were fine with it. my sh held at 35 the whole time seems a little high but from what im reading and getting advice about it, 20 to 40 for refrigeration boxes seems to be the norm. a/c is so easier to calculate sh with my handy sh calculater and a wet bulb temp. hmmm any thoughts on subcooling for a box with a txv ?
The under cabinet is supposed to be a light freezer. Many of them have electric defrost. :eek::eek: He has a double duty case. Display on top with storage on the bottom. :confused: Why would he want a light freezer ?
We have had this problem and aleviataed it using an EPR valve on the lower coil.
I may not know as much as my cousin, but this is a standard fix.
Maybe "Andy Schoen" would like to comment on this/
I did not design the thing or buy them, but I have see several of them.
I read the manual on one.
Why else would they put electric defrost on it?
Burnerfixer
12-03-2008, 07:58 AM
well they were not the owners were not interested in having me install a epr for the lower box, i adjusted thermostat to hold the display case on top at 35 and the lower none visible box was at 27 they were fine with it. my sh held at 35 the whole time seems a little high but from what im reading and getting advice about it, 20 to 40 for refrigeration boxes seems to be the norm. a/c is so easier to calculate sh with my handy sh calculater and a wet bulb temp. hmmm any thoughts on subcooling for a box with a txv ?
It is recommended to check sub-cooling on TXV systems (10*-15*F.)
Remember that TXV's maintain a constant "Superheat"
Kim, just because a coil has an electric heater doesn't mean the box is a freezer. :)
True, the best beer boxes have electric evap heaters.
The under box storage does a great job of keeping product just below freezing, it is hard to imagine they are not doing the job they were designed to do. That is unless they were designed by idiots.
Kelly T
12-06-2008, 09:31 PM
im not familiar with an epr valve but would like to hear more about it. the way it is now is evrything piped together, one thermostat the bottom is a insulated none visible box as the top is totaly visible
EPR= Evaporator Pressure Regulator purpose is to keep the back*suction* pressure up so the evap doesn't freeze *easiest way to explain it* they are also used on large multi-evap walkin systems *hussman comes to mind* they work very well till someone that doesn't have a clue what they are doing messes with them:eek: you may not see very many on the type of equipment you work on, are very common in True reach in freezers.
intellitech
12-06-2008, 10:35 PM
EPR= Evaporator Pressure Regulator purpose is to keep the back*suction* pressure up so the evap doesn't freeze *easiest way to explain it* they are also used on large multi-evap walkin systems *hussman comes to mind* they work very well till someone that doesn't have a clue what they are doing messes with them:eek: you may not see very many on the type of equipment you work on, are very common in True reach in freezers.
What model of a TRUE reach-in freezer have you seen an EPR? I have never heard or seen such a valve in a TRUE reach-in. In my TRUE technical service manual an EPR is never even mentioned as being used. Am I missing something? Let me know....
Burnerfixer
12-07-2008, 07:08 AM
:) Me thinks Kelly T is a little mixed up. He is stating about CPR not EPR.
Burnerfixer
12-07-2008, 07:09 AM
True, the best beer boxes have electric evap heaters.
The under box storage does a great job of keeping product just below freezing, it is hard to imagine they are not doing the job they were designed to do. That is unless they were designed by idiots. Not idiots, engineers. :D
EPR is like an AXV. It is before the Evap
CPR is before the compressor. I see it most on freezers without a pumpdown. It is very common on Victory, where it keeps the compressor from overloading after defrost. It is also on dual temp boxes with one compressor.
Other than that they are basically the same thing.
intellitech
12-07-2008, 04:39 PM
EPR is like an AXV. It is before the Evap
CPR is before the compressor. I see it most on freezers without a pumpdown. It is very common on Victory, where it keeps the compressor from overloading after defrost. It is also on dual temp boxes with one compressor.
Other than that they are basically the same thing.
An EPR is like an AXV in the sense that both respond to evaporator pressure. But their respective applications are different. EPR's are of course used in multiple evaporator applications, but an AXV would not be used in this particular application. AXV's are to be used when the evaporator heat load is rather constant (some good examples are ice cream and frozen drink-slush-dispensers as these require close product temperature ranges).
Burnerfixer
12-08-2008, 09:44 AM
Automatic Expansion Valve—An automatic expansion valve maintains a constant pressure in the evaporator. Normally this valve is used only with direct expansion, dry type of evaporators. In operation, the valve feeds enough liquid refrigerant to the evaporator to maintain a constant pressure in the coils. This type of valve is generally used in a system where constant loads are expected. When a large variable load occurs, the valve will not feed enough refrigerant to the evaporator under high load and will overfeed the evaporator at low load. Compressor damage can result when slugs of liquid enter the compressor.
jpsmith1cm
12-08-2008, 10:10 AM
EPR is like an AXV. It is before the Evap
Umm. No.
Epr and cpr would pipe in the same spot in the circuit. Between the evap and the compressor.
The EPR regulates the pressure in the evaporator. It is an inlet pressure regulating valve. Setting the EPR means to set the lowest pressure that you want the evap to reach. This can be used for very precise temperature control on parallel systems.
A CPR, on the other hand, regulates the pressure in the compressor. It is an OUTLET pressure regulating valve. This sets the MAXIMUM pressure allowable in the compressor crankcase. Typically, a cpr is set by compressor amperage.
Where EPR and AXV are similar is that they tend to hold a steady pressure. It is achieved on opposite ends of the coil and by different means.
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