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Old 13-04-2013, 10:38   #16
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Re: Fridge high current draw

Hi

fridge has been running overnight at high thermostat setting.
The evaporator appears to have pretty even frosting over whole plate, I am guessing that the ice on lower plate is there from freezing the water that settled when we had it at our more usual low thermo setting ?

I had previously fitted an extra cooling fan to the condenser and this still appears to be doing its job so condenser cooling shouldn't be an issue. FYI extra fan only draws 0.24 amps.

The original leak and resolder was carried out where one of the pipes goes into the condenser, sorry I didnt see, or ask, which one. Foolishly I believed the guy knew what he was doing !!!
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Old 13-04-2013, 14:36   #17
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Re: Fridge high current draw

If unit is still performing poorly, amperage is above normal and a restriction in flow can not be located by a cold spot in refrigerant line then it is time to start over.

Remove refrigerant, dehydrate system for 4 hours if this is a 134a unit keeping complete system at near 100 degrees F and refill with fresh pure 134a.

If this is a Freon R12 system one hour on vacuum pump with complete system at 70 degrees F cabin temperature and refill with only R12 refrigerant. NO Substitutes unless operated in a cool climate.
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Old 13-04-2013, 15:38   #18
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Re: Fridge high current draw

If I remove the 134a will that also remove any "non compressible" ? or is this what the "dehydration" is for?
I assume dehydration just means leaving the system open so that it can vent ??

Is it possible the soldered repair has introduced a compression point where there isnt meant to be one or that they pinched a tube whilst moving the compressor around to get access ?
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Old 13-04-2013, 16:20   #19
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Re: Fridge high current draw

dehydration is not venting.
a vacuum pump as it runs sucks out everything that can vaporize like water or refrigerants.
if a capillary tube system is wet it likely will freeze the water in the tubing and can block the capillary tube, then you get no cooling and the high pressure side goes very high. happened to me on a fridge i recharged long time ago. charging by weight is what you want to do, imo.

also was the drier replaced??

I think the system may be overcharged so putting a higher load on the compressor and using more amps.
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Old 13-04-2013, 17:58   #20
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I actually think there is air in the system. I had that with my old system once and got high amps with little cooling so same troubles.

With R134a, which is in the Frigoboat systems, it is more difficultto get moisture out because the oil used is not so much wanting to let it go. That is why Richard states it needs to be evacuated with the vacuum pump longer and at a higher temperature. I achieved that by using a heatgun, tracing all the components and concentrating on any filter-driers incl. that small one behind the compressor.

To avoid cheating techs I bought my own vacuum pump, gauge set etc. For these small systems you only need a small pump and they are somewhat affordable. I got mine from Amazon.
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Old 13-04-2013, 18:13   #21
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Re: Fridge high current draw

If refrigerant is removed to zero pressure there will still be atmosphere pressure of 14.7 psi in system. The vacuum pump will remove vapor gasses including air easily but not water droplets. Extended deep vacuuming will cause water to phase change to vapor that can then be removed as vapor. Your overnight test and evaporator still frosted normally indicates refrigerant not blocking capillary tube but this may not confirm that moisture ice is not restricting flow in evaporator. A warm system while vacuuming with a good refrigerant vacuum pump will also remove moisture from filter dryer.

On this type system refrigerant blockage with the correct refrigerant charge after condenser will not cause increased amperage. When not able to pin point location of repair the next step is to go through the vacuum process and re-service test before opening up system to find flow restricting area. With correct charge when re-serviced at 10 to 20 minutes running time amperage should not exceed 5.5 amps. Add no more refrigerant than after 20 minutes as amperage will drop some as plate cools. Suction pressure at this 20 minute point will be in a range from 6 to 12 pis.

Comments to others who are interested in this troubleshooting process.

Use of textbook knowledge suggested in this thread is good but you must know how to apply it to today’s pleasure boat refrigeration systems. Most of these pleasure boat units are designed with separate condensing units and evaporators to be installed in existing iceboxes. There are no large companies building these systems most all kits are products of small job shops. If anyone believes they have a textbook that guides you through the proper servicing of the many various 1/18 horse Power and smaller refrigeration units, other than Superheat, amperage and pressure, I would like to see it.

A Danfoss BD50 and BD35 compressor systems with capillary tube are very common in pleasure boat refrigeration they contain 55 to 120 grams of refrigerant depending on design of evaporator and compressor’s preset speed. Yes, Manufacturers of cabinets and separate component pre-charged kits do weight refrigerant charge. This correct weight of refrigerant charge is most often not available in the field. Nor would a local service technician have a charge cylinder or weight scale accurate enough to plus or minus 5 grams (0.18 of an Ounce).
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Old 02-05-2013, 14:39   #22
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Re: Fridge high current draw

Quote:
Originally Posted by SeaBuffalo View Post
The end of your response was totally uncalled for.

Frigoboat's instructions are NOT the industry norm. There is a lot of room for error with just looking for frost on a line because of too many variables.

As someone who was professionally schooled with fifteen years in refrigeration I can tell you that a manufacture not specifying charge weight or offering a charging chart is not industry standard.

What they are offering in their manual is a way to charge a system that appeals to DIY people with minimal experience or tools but at the risk of flooding the compressor or starving it with high superheat.
Frigoboat was the first manufacturer to offer "mix-and-match" components as opposed to a system where the components had been coupled together, charged, and then separated. This was, and still is, achieved by charging the individual components with a very precise refrigerant charge which is added under constant temperature conditions. Yes, in theory Frigoboat could tell you the precise amount of refrigerant in the individual components plus the precise temperature of the components and refrigerant, but that would be a pointless exercise as it is not practical to attempt to replicate these laboratory-like conditions in the field.
The perfectly charged capillary refrigeration system is one where there is sufficient refrigerant to be evaporating all through the channels in the evaporator but ending where the suction tube leaves the plate. End. Pressures and current draw can be used as a guide to ensure that they are within expected limits and to check for other anomolies, but the end result must be as I have stated above for a perfect charge. This is not just a simple DIY approach, as SeaBuffalo suggests, but is how refrigeration technicians as well as boat operators should be checking the refrigerant level. Charging must be done slowly and methodically, leaving ample time between additions of refrigerant for these small-capacity systems to recover and settle down. Too much refrigerant and there will be frosting on the lines leaving the evaporator (or even sweating on the compressor and lines if there is a massive overcharge). Too little refrigerant and the evaporator will not be frosted over it's entire surface. It's as simple and as basic as that!
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Old 02-05-2013, 14:55   #23
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Re: Fridge high current draw

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Originally Posted by Richard Kollmann View Post
Most of these pleasure boat units are designed with separate condensing units and evaporators to be installed in existing iceboxes. There are no large companies building these systems most all kits are products of small job shops. .
I hope you'll reconsider that statement Richard, as it is totally inappropriate and appears to be very demeaning. Veco (Frigoboat), Rivacold (Vitrifrigo), Indel (Isotherm), Dometic (Waeco, Grunert, Adler Barbour), Nova Kool .... these could not possibly be considered by any stretch of the imagination as "small job shops".
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Old 02-05-2013, 18:43   #24
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Re: Fridge high current draw

Frigoboat Info, there is nothing wrong with Job Shops that put together Boat refrigeration and recreational refrigerators but from my experiences they do not and can not provide services of large manufacturers. Manufacturers have Design groups, Quality control personal and way more than one or two experiences technical services engineers. If you must talk to the Present of one of these companies to get action or warrantee solution it must be a Job Shop. One of the most important difference between job shops and manufactures is recognizing defects and correcting them or at least informing industry people of how to handle these deficiencies. How many service bulletins have you seen from companies who make and sell Boat Refrigeration? The companies you listed I would not consider manufactures although I do recommend items in their product line when the right application is there, sorry unknown person but these are my opinions.

In summary thank god we have Job Shops if not for them we would not have refrigerators for our pleasure boats.
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Old 02-05-2013, 19:31   #25
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Quote:
Originally Posted by Frigoboat Info View Post
The perfectly charged capillary refrigeration system is one where there is sufficient refrigerant to be evaporating all through the channels in the evaporator but ending where the suction tube leaves the plate. End. Pressures and current draw can be used as a guide to ensure that they are within expected limits and to check for other anomolies, but the end result must be as I have stated above for a perfect charge. This is not just a simple DIY approach, as SeaBuffalo suggests, but is how refrigeration technicians as well as boat operators should be checking the refrigerant level. Charging must be done slowly and methodically, leaving ample time between additions of refrigerant for these small-capacity systems to recover and settle down. Too much refrigerant and there will be frosting on the lines leaving the evaporator (or even sweating on the compressor and lines if there is a massive overcharge). Too little refrigerant and the evaporator will not be frosted over it's entire surface. It's as simple and as basic as that!
I understand the reasoning and after thinking about it see why this is the best overall recommended charge method for the style and variety of systems you guys produce.

The reason for my statement is because most professional hvac techs have fought against the charging methods of systems like "as long as there is a quarter sized frost around suction line a the compressor it's good" or "the line should be beer can cold for a proper charge". Or having techs tell me a low temp compressor is flooding back because there is frost on the compressor head even though it has 20 degrees of superheat.

Frost patterns are good for looking for plugged distributors or bad TXVs but not seeing superheat, sub-cooling, delta-t and temp glide (with these new refrigerants) and just looking at a frost line is hard to get used to.
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Old 02-05-2013, 20:56   #26
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Re: Fridge high current draw

SeaBuffalo,What is not considered in refrigerant charging by HVACR training schools is the affects on refrigerant volume in a small 12 volt mobile refrigerators where 15 grams of refrigerant is critical to performance. Very few of these systems use TXV flow control devices and none use high pressure control devices to adjust for condenser cooling medium, air and water temperature changes. A technician with experience understands that as climate condition change refrigerant charge that controls super heat (Frost Line) on cap tube systems will change.
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Old 03-05-2013, 00:08   #27
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SeaBuffalo,What is not considered in refrigerant charging by HVACR training schools is the affects on refrigerant volume in a small 12 volt mobile refrigerators where 15 grams of refrigerant is critical to performance. Very few of these systems use TXV flow control devices and none use high pressure control devices to adjust for condenser cooling medium, air and water temperature changes. A technician with experience understands that as climate condition change refrigerant charge that controls super heat (Frost Line) on cap tube systems will change.
Yes I understand how climate condition causes change in capillary tube systems like how low condensing temp can cause capacity loss because of lower pressure and lower pressure drop on the cap tube or the inverse. This is why on larger systems with a fixed metering device like flow piston they have a charging chart that takes into account inside and out temps.

My whole point is 99.9% of small charge capillary tube systems are a fixed design with a specified charge for the system that has been determined by the manufacture to cover the rated operating conditions of the appliance and therefore looking for frost patterns or checking superheat isn't needed (boat ac, soda machines, water fountains, household frig/freezers, etc). This allows for quick servicing and happy customers who wonder why you have to watch it for a hour once its running ( ice machines).

The procedure of charging a sailboat refrigerator or freezer by looking for frost lines is the exception to the rules of normal charging even when compared to other capillary tube systems of comparable size due to their "mix and match design " and very small charge.

Personally if it was me building a system I would put a small TXV and a one LB receiver to make charging much simpler and less expensive to the customer. With the charging method of looking at frost lines results in more time watching the system and ticking off I mean billing the customer.
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Old 03-05-2013, 01:33   #28
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Re: Fridge high current draw

I think it's overcharged. Let out refrigerant for 5 seconds, wait a couple hours and see if it's still cold enough and if the current draw is less. If not, try another 5 seconds. What do you have to lose? As it stands now you need to either buy tools and a book or call a different fridge tech. If you let out a little too much refrigerant you need to buy tools or call the guy.
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Old 03-05-2013, 01:39   #29
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Re: Fridge high current draw

Quote:
Originally Posted by Richard Kollmann View Post
If refrigerant is removed to zero pressure there will still be atmosphere pressure of 14.7 psi in system. The vacuum pump will remove vapor gasses including air easily but not water droplets. Extended deep vacuuming will cause water to phase change to vapor that can then be removed as vapor. Your overnight test and evaporator still frosted normally indicates refrigerant not blocking capillary tube but this may not confirm that moisture ice is not restricting flow in evaporator. A warm system while vacuuming with a good refrigerant vacuum pump will also remove moisture from filter dryer.

On this type system refrigerant blockage with the correct refrigerant charge after condenser will not cause increased amperage. When not able to pin point location of repair the next step is to go through the vacuum process and re-service test before opening up system to find flow restricting area. With correct charge when re-serviced at 10 to 20 minutes running time amperage should not exceed 5.5 amps. Add no more refrigerant than after 20 minutes as amperage will drop some as plate cools. Suction pressure at this 20 minute point will be in a range from 6 to 12 pis.

Comments to others who are interested in this troubleshooting process.

Use of textbook knowledge suggested in this thread is good but you must know how to apply it to today’s pleasure boat refrigeration systems. Most of these pleasure boat units are designed with separate condensing units and evaporators to be installed in existing iceboxes. There are no large companies building these systems most all kits are products of small job shops. If anyone believes they have a textbook that guides you through the proper servicing of the many various 1/18 horse Power and smaller refrigeration units, other than Superheat, amperage and pressure, I would like to see it.

A Danfoss BD50 and BD35 compressor systems with capillary tube are very common in pleasure boat refrigeration they contain 55 to 120 grams of refrigerant depending on design of evaporator and compressor’s preset speed. Yes, Manufacturers of cabinets and separate component pre-charged kits do weight refrigerant charge. This correct weight of refrigerant charge is most often not available in the field. Nor would a local service technician have a charge cylinder or weight scale accurate enough to plus or minus 5 grams (0.18 of an Ounce).
Seriously? Every head shop in the world sells scales way more accurate than that. There are thousands on ebay. Thousands more on Amazon. Less than a hundred bucks. What prevents a professional from buying one?
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Old 05-05-2013, 13:53   #30
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Re: Fridge high current draw

Thegoodshipmagn, in following this thread, I can see no mention that the system was vacuumed after the repair was made on the line to/from the condenser. As Mr. Kollmann mentioned, it is very possible that air, and the moisture in it, was introduced at that time. The air, being non condensable at condenser temperatures and pressures, will stay in the condenser and reduce the heat transfer to the atmosphere. The moisture can freeze to ice in the capillary tube and restrict or block the flow. Therefore both the air and moisture will tend to raise the discharge pressure. Since you have not mentioned the discharge pressure, I assume you have no gauges, or the system has no tap on the discharge side. If this is so, with the unit running, try checking the temperature on the line leaving the condenser. If you have no way of measuring the temperature, feel the difference with your hand between the line entering the condenser, and the line leaving the condenser. The line entering the condenser is often so hot that you cannot leave your hand on it. However, the line leaving the condenser should not be much warmer that body temperature. If it is warmer, the condenser is not removing the heat adequately due to too warm ambient air, air and/or moisture in the refrigerant (the system needs a thorough vacuuming), or too much refrigerant in the system.
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