Input needed: New fridge system for our Dufour 35

[OzePete]

Originally Posted by Richard Kollmann

Pete if you expect to sell boat refrigeration other than in Australia close to your shop you need to address and solve problems in the best way possible. Richard, what on earth are you talking about? This diversion has nothing to do with the tread, but I don't want yet another of your lame attempts to discredit my company to go unchallenged, so I shall respond. Firstly your advice on anything regards marine refrigeration, system manufacture or distribution, is not of any interest to us, thank you. Secondly we don't EXPECT to sell worldwide, we ALREADY DO sell worldwide!

Your websites solution to return unit to factory will not work on an island 12,000 miles away with only unskilled people. Generally in these remote areas of the world boaters have to rely on other boaters for servicing equipment and pure refrigerant.
Really Richard? Here is what our Warranty statement says: WARRANTY: Ozefridge provides a minimum of 12 months warranty with 5 years on the compresor subject to the conditions described in the owners manual. This warranty is limited to the supply of replacement parts by post or a complete unit rebuild if the unit is returned to Ozefridge. We do not reimburse costs incurred as a result of unauthorised work carried out by others. OK Richard, tell me what is so difficult about that and how it is lesser that any others

I have told you before bad advice to a boater on other than your own refrigeration design will lose you future sales.(OMG you sound like an agree father! Perhaps I should stay in the naughty corner ) Just don't understand why you would think that we would be the slightest bit interested in what you have to say. Did we solicit your advice, I think not!

And talking about BAD ADVICE Richard, do you still advise that high side pressure should not exceed 120PSIG and that you cant read input power supply voltage drop with a multi-meter or that water will not dissipate heat faster than air! Shall I go on?

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[Richard Kollmann]

(Quote)
And talking about BAD ADVICE Richard, do you still advise that high side pressure should not exceed 120PSIG and that you cant read input power supply voltage drop with a multi-meter or that water will not dissipate heat faster than air! Shall I go on?

Pete your lack of knowledge of mobile boat refrigeration is dangerous to those seeking help. This pleasure boat industry is small and not a good place for a poor attitude salesperson. Your above out of texted statement is just one more example of uninformed silliness.

[Richard Kollmann]

Really Richard? Here is what our Warranty statement says: WARRANTY: Ozefridge provides a minimum of 12 months warranty with 5 years on the compresor subject to the conditions described in the owners manual. This warranty is limited to the supply of replacement parts by post or a complete unit rebuild if the unit is returned to Ozefridge. We do not reimburse costs incurred as a result of unauthorised work carried out by others. OK Richard, tell me what is so difficult about that and how it is lesser that any others.

I do not know of anyone that has question your warranty it sounds average for this type refrigeration system. Only Electric Iceman in Miami had a better Warranty lifetime on parts for a one time cost of $25. The last time I was at the Miami boat show the daughter of the company founder said they still honored this 30 year old warranty. The companies that fail to be liberal in settling claims are the ones with bad press.

[txg]

We had a technician on board this morning. He refilled the system and now the evaporator is getting cold. We will finish the install now and then do some further testing.

[Richard Kollmann]

Originally Posted by txg

We had a technician on board this morning. He refilled the system and now the evaporator is getting cold. We will finish the install now and then do some further testing.

After your system has operated 24 hours please report the amount of evaporator surface area covered with frost, 50% 75% 90% and is there frost on refrigerant line outside refrigerated box? If there is frost on this line how close is frost to compressor? If you know the amp draw of unit after it ran for a while it would be good to know now and later to make sure there are no slow leaks.

[txg]

So for now, the system is running good (though only as a refrigerator, no spillover system yet). There is a small amount of frost on the evaporator on maybe a little bit more than the lower 50%, but none on the refrigerant line.


The compressor is running at 2000rpm (no resistor connected) and pulls 3amps according to my clampmeter. Even at this rpm setting it gets quite hot. The thermostat is attached to the top end of the evaporator and switches on at 7deg C and off at 4deg C. This gives about 1deg C at the bottom of the compartment where we store our drinks. The cheap digital thermostat i used works very nice, it helps a lot to understand what is going on in the fridge.


Compressor off-time is 6.5mins and on-time 9mins. This makes a consumption off about 42Ah/day. Not too bad for a 100L fridge in the tropics, but not spectacular as well. At least thats about half of what our ancient 40-year-old Engel Fridge uses, which is way smaller at about only 14L capacity.


What needs to be optimized is the insulation of the lids, currently we just put a blanket over them. Also we need to find a way to provide the compressor compartment with fresh air, else it will get way to hot in there. The testing numbers stated above are with open locker doors and a small fan blowing into the compartment.

[john61ct]

The effective extraction of heat from the condenser and electronics areas will noticeably improve efficiency.

Adding insulation to the top not so mich, as long as it seals well.

Only minimal heat is migrating downward, it's the bottom of the box needs the most insulation.

[OzePete]

Originally Posted by txg

We had a technician on board this morning. He refilled the system and now the evaporator is getting cold. We will finish the install now and then do some further testing.

Did the tech locate a gas leak and repair it?
Did he replace the filter dryer and did he evacuate the system before re-gassing it?
If these things were not done then unfortunately your system will never perform correctly.

Cheers OzePete

[Richard Kollmann]

Originally Posted by txg

So for now, the system is running good (though only as a refrigerator, no spillover system yet). There is a small amount of frost on the evaporator on maybe a little bit more than the lower 50%, but none on the refrigerant line.


The compressor is running at 2000rpm (no resistor connected) and pulls 3amps according to my clampmeter. Even at this rpm setting it gets quite hot. The thermostat is attached to the top end of the evaporator and switches on at 7deg C and off at 4deg C. This gives about 1deg C at the bottom of the compartment where we store our drinks. The cheap digital thermostat i used works very nice, it helps a lot to understand what is going on in the fridge.


Compressor off-time is 6.5mins and on-time 9mins. This makes a consumption off about 42Ah/day. Not too bad for a 100L fridge in the tropics, but not spectacular as well. At least thats about half of what our ancient 40-year-old Engel Fridge uses, which is way smaller at about only 14L capacity.


What needs to be optimized is the insulation of the lids, currently we just put a blanket over them. Also we need to find a way to provide the compressor compartment with fresh air, else it will get way to hot in there. The testing numbers stated above are with open locker doors and a small fan blowing into the compartment.

If this is a BD50 compressor running at 2000 rpm and only drawing 3 amps with only lower half of evaporator frosted, there is not enough refrigerant in system. The cycle times are also backwards. This unit would normally have an evaporator temperature inside box of -11 degrees C and a refrigerator section temperature of around + 5 C, When thermostat stops compressor.

[txg]

@john61ct:


Currently there is about 5-7 inch of insulation on the bottom but only one inch on the top. The topsides get very cold outside, so there is definitely some efficiency to gain there.



@OzePete:


As this is a new system there should be no leak. My guess is that the red plastic caps have loosened when the system was shipped. Also, i don't understand why the filter dryer should be changed on a new system that has never run before. The technician just filled up R134a and now it works fine.


@Richard Kollmann:
Yes, it is a BD50. I don't understand your answer about the evaporator temperatures. . As written before, i'm using a digital thermostat to control the compressor, and so the numbers that i got are exactly what i put in the control unit.



Regarding the frosting, i just put the thermostat to -10 deg C to make the compressor run permanently, now most of the evaporator is frosted. This is also something that probably has to do with not enough insulation on the top hatches.



Regarding the 3 amps, that's something that makes me wonder as well...will continue to monitor that and if that's a sign for not enough refrigerant i should probably call the technician again.

[Richard Kollmann]

Originally Posted by txg

@john61ct:


Currently there is about 5-7 inch of insulation on the bottom but only one inch on the top. The topsides get very cold outside, so there is definitely some efficiency to gain there.



@OzePete:


As this is a new system there should be no leak. My guess is that the red plastic caps have loosened when the system was shipped. Also, i don't understand why the filter dryer should be changed on a new system that has never run before. The technician just filled up R134a and now it works fine.


@Richard Kollmann:
Yes, it is a BD50. I don't understand your answer about the evaporator temperatures. . As written before, i'm using a digital thermostat to control the compressor, and so the numbers that i got are exactly what i put in the control unit.



Regarding the frosting, i just put the thermostat to -10 deg C to make the compressor run permanently, now most of the evaporator is frosted. This is also something that probably has to do with not enough insulation on the top hatches.



Regarding the 3 amps, that's something that makes me wonder as well...will continue to monitor that and if that's a sign for not enough refrigerant i should probably call the technician again.

Did you follow my earlier instruction to add refrigerant after unit ran more the 20 minutes until amperage stabilized to around 6 amps? This way after 24 hours frost coverage, amperage and temperatures will confirm action taken was correct.

I run these systems with evaporators like yours on the work bench in controlled +27 degree C test area with correct volume of refrigerant 90% of evaporator will be covered with frost and no insulation. Frost may be just a thin layer but it is the cover not the thickness of frost that is important.

[txg]

Originally Posted by Richard Kollmann

Did you follow my earlier instruction to add refrigerant after unit ran more the 20 minutes until amperage stabilized to around 6 amps? This way after 24 hours frost coverage, amperage and temperatures will confirm action taken was correct.

No, i did not. I had a technician coming over whose english skills are as good as my french skills


He instantly started refilling after the compressor started and he did not measure amp draw. Just watched his pressure gauge while adding small shots of refrigerant.



Maybe i should get a small can of r134a myself. Probably easier than paying the "pros" down here again and again.



Thanks for your help so far!


I will let the system run as it is till tomorrow and measure current draw again to make sure there are no leaks. And then i will decide if i call the technician again or go hunt for a refill system myself.

[Richard Kollmann]

txg, Most small refrigeration systems like yours with evaporator freezer chamber control evaporator temperature with thermostat. It seems like in most cases when this freezing chamber is kept at -11c (+12 F). Ice cube production once a day is possible and a few items can be kept frozen. If you are lucky the temperature in refrigerator section of box will be between 33 and 36 degrees F when freezing chamber is at +12 degrees F.

Your thermostat does not need to control evaporator temperature as long as it is set so it produces a freezing temperature inside evaporator chamber without freezing items in refrigerator section. There are tricks to control this temperature difference by adding insulation behind or below evaporator.

[OzePete]

.
TXG: QUOTE:
As this is a new system there should be no leak. My guess is that the red plastic caps have loosened when the system was shipped. Also, i don't understand why the filter dryer should be changed on a new system that has never run before. The technician just filled up R134a and now it works fine.

[/QUOTE]

The ONLY reason a system requires gas added or total re-gas is because gas has leaked out and once that refrigerant leaks out air (along with moisture) can and does contaminate the system. This being new it could have been in a zero gas pressure situation with a leak for some time.
The tech should have located and repaired the leak, replacing the filter dryer and evacuated the system before adding refrigerant to suction gauge pressure.

Not following this correct procedure won't necessarily prevent the system from running but can greatly reduce its longevity and power efficiency.

If you are going to risk adding car air-con grade R134a refrigerant, at least avoid any cans that have any additives at all, regardless of how 'you bute' the wrap on the can says it is!

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[Richard Kollmann]

Originally Posted by OzePete

.
TXG: QUOTE:
As this is a new system there should be no leak. My guess is that the red plastic caps have loosened when the system was shipped. Also, i don't understand why the filter dryer should be changed on a new system that has never run before. The technician just filled up R134a and now it works fine.

The ONLY reason a system requires gas added or total re-gas is because gas has leaked out and once that refrigerant leaks out air (along with moisture) can and does contaminate the system. This being new it could have been in a zero gas pressure situation with a leak for some time.
The tech should have located and repaired the leak, replacing the filter dryer and evacuated the system before adding refrigerant to suction gauge pressure.

Not following this correct procedure won't necessarily prevent the system from running but can greatly reduce its longevity and power efficiency.

If you are going to risk adding car air-con grade R134a refrigerant, at least avoid any cans that have any additives at all, regardless of how 'you bute' the wrap on the can says it is!

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems[/QUOTE]

Pete what do you recommend he do? Maybe you do not understand the mechanic does not speak English. And maybe a experienced tech is 1000 miles away. I have run training classes down island where mechanics make only ten dollars a day. Your advice is like telling him to shoot himself in the foot and he will feel better.

When we get a report back confirming system is performing well and no leaks Dehydration in a few months might be a good idea but defiantly not a replacement of filter dryer. Risking a solder to line is old school for suspect moisture.