Visit our Popular Forums

ColdEH · 12-10-2016, 07:04

Quote:

Originally Posted by SV THIRD DAY

BSGTS
(Boat Service Guy True Story)

A cruising boat stops by Morro Bay on their way South to Mexico knowing that I'm hiding out there until my triumphant return to Mexico myself. He bought a boat with a 18yr old CoolBlue on it and the compressor was running all the time had not cycled off in the year he had owned the boat. The boat has lived in the Stockton Delta area with lots of dust and poor air quality. So after arranging payment terms of a Taco lunch, I headed over to his boat for a look see. Holding plate looked good, and then I saw the biggest, hairyiest, fuzz ball of a condenser I've even seen in my life. The entire condensing unit was so jam packed with cat hair and boat dandruff that there wasn't a clear space showing on the condenser. I had to take it out of the locker and hose it off on the dock to clean it off it was so bad. (after removing the fan and control module of course). By the time we got back from the taco place for lunch, their unit was cycling on and off normally and off to Mexico they went.

Hey this may work to his advantage , good way to get rid of all that ice . Let the condenser get hot , lengthens the bubble length in the cap tube and throttles back the refrigerant flow , viola no more ice LOL !!

Regards

**a64pilot** · 12-10-2016, 08:10

I thought to defrost, you switched the pos and neg terminals so the compressor would run backwards and melt the ice?

ColdEH · 12-10-2016, 08:33

No you can't reverse the polarity on the danfoss controllers , they just don't work. lucky they are protected against this, they don't blow up . Looks like you just have to turn it off and wait .

Regards

**a64pilot** · 12-10-2016, 08:51

Poor joke, I usually run water over mine as it's an ice box conversion and has a drain, takes about 5 min that way.
Mine are cold plates, and I'd guess would take at least a full day to just thaw out if left alone and then another half day or so to freeze back down, food would be unfrozen by then.

ColdEH · 12-10-2016, 08:53

I thought that was a little weird LOL

Regards

BlackAdder · 12-10-2016, 09:03

Thannks ramblinrod, donradcliffe, skipgundlach, Rich, John, leftbrainstuff, typhoon, and anyone else I may have missed.

I jumpered C-T terminals so the fridge would run constantly so I could see what the limits of the system and the insulation were. Here are my results after 24 hours. After defrosting the evaporator and clearing out the water, I put the fridge back on running 100% of the time, temps are:

Evaporator is ranging from 23-25°F (-4 - -5°C) depending on where I shoot.

Box is ranging from 48-57°F (9-14°C). So not really much better than before actually.

The evaporator is already covered with 1/4" of frost on the bottom and about 1/2" of what looks like ice on the top (within 24 hours remember).

Ambient temperature is 86°F (30°C).

Temperature under the galley sink in the cabinet where the compressor sits is 93°F (34°C).

Conclusions:

1. Friggin' Frigobat is actually functioning correctly and I disparaged it needlessly. I think the problem is that here in the tropics I need a lot more insulation on the box or a more powerful system. Uneven box temps show the insulation is very uneven.

2. The amount of frost accumulation tells me the seals are probably allowing in some air.

3. I need to provide additional ventilation to the cabinet under the sink as the compressor sits in an enclosed space without enough outside airflow or a way to expel the hotter air.

4. I read on the forum about the STC1000 electronic thermostat. I think I'd like to get one so I can see the temperature at a glance to know the system is working and also apparently it can be programmed to do auto-defrosting once a week.

5. If the system was low on gas then I wouldn't expect to see such good evap temps. I don't think the evap could get much colder and the frost is even.

Who's with me on this? Have I drawn the correct conclusions here or what?

ColdEH · 12-10-2016, 09:14

Question, did you get any frost on the suction line going back to the compressor?

Regards

**a64pilot** · 12-10-2016, 09:15

Maybe jumpering it has it running continuously, but in low speed? SO it may function better with the thermostat plugged in.

But either way I think DeepFrz is right, fix your seals and insert additional insulation to the inside of the box, increasing insulation which will help of course, but also decreasing box size

skipgundlach · 12-10-2016, 09:21

Sounds like it to me. Is your frost line on the return at the exit?

As to heat removal, particularly with an air-cooled unit, it will make a huge difference. Ours is an enclosed, ducted-out system, but it's in the engine room; there's a significant drop in efficiency as the temps rise on engine use, even though we leave the ER doors open, a huge cooling influence.

Seals and insulation are also key; your rate of BTU inrush is directly related to the insulation, and water vapor to opening doors or seals or both.

My preference to the "D" weatherstrip is one which has a soft-edged curl to it. It's commonly available in Home Depot, which I recognize isn't where you are. It's MD#43846, barcode 0-43374 43846 - 8 (leading and ending characters not hyphenated but smaller and separated from the actual barcode stripes)...

ka4wja · 12-10-2016, 10:55

Black Adder,
I'm not familiar with the "jumpering" to get it to run continuously, but if this Frigoboat unit has a multi-speed controller (??), then A64's point is very valid...why not just let it run with the thermostat at "7", and no "jumpering"???

And again, while I'm certainly no Richard Kollmann, here are my thoughts:
a) your evap temps look a too high to me (23*-25*F)....
b) your evap has way too much frost / ice on it for just 24 hours of operation! (I would expect that in a week or so, for typical factory set-ups, in the humid tropics....but not in just 24 hours!)

c) you need better airflow thru / around the condenser...
d) you need more insulation!! and better box sealing!!

The first two ("a" and "b"), makes me suspect something just might be amiss with your Frigoboat unit, but since the airflow thru the condenser is suspect and you've "jumpered" it, and I don't know the size of your box(es), so I'm not sure if I can be certain of it (hopefully Rich Boren will chime in here)....

And of course, better insulation and box sealing will always help!!

Some specifics, in red...

Quote:

Originally Posted by BlackAdder

Here are my results after 24 hours. After defrosting the evaporator and clearing out the water, I put the fridge back on running 100% of the time, temps are:

Evaporator is ranging from 23-25°F (-4 - -5°C) depending on where I shoot.

Box is ranging from 48-57°F (9-14°C). So not really much better than before actually.

The evaporator is already covered with 1/4" of frost on the bottom and about 1/2" of what looks like ice on the top (within 24 hours remember).

Ambient temperature is 86°F (30°C).

Temperature under the galley sink in the cabinet where the compressor sits is 93°F (34°C).

Conclusions:

1. Friggin' Frigobat is actually functioning correctly and I disparaged it needlessly.
Maybe, maybe not....
As I wrote above, I can't be sure...it may have an issue..

I think the problem is that here in the tropics I need a lot more insulation on the box or a more powerful system.
Yes, this will certainly help, a LOT!
But, it all depends on if the unit is actually working as it should, and what size box(es) you have to cool...

Uneven box temps show the insulation is very uneven.
Yes, and also that airflow is not good throughout the box...
Go and buy some insulation board!!
Look at the article I referenced, for a detailed description of what I did, and how I got it t work well!!
Frig/Freezer

2. The amount of frost accumulation tells me the seals are probably allowing in some air.
Yes, and maybe also be a sign of something else (possibly a problem or possibly caused by"jumpering"???)

3. I need to provide additional ventilation to the cabinet under the sink as the compressor sits in an enclosed space without enough outside airflow or a way to expel the hotter air.
Yes, absolutely!

4. I read on the forum about the STC1000 electronic thermostat. I think I'd like to get one so I can see the temperature at a glance to know the system is working and also apparently it can be programmed to do auto-defrosting once a week.
I'll let others with experience with the STC1000 chime in...
But, in my opinion, there is no need for anything "fancy", these Danfoss systems are fool-proof and reliable, why muck 'em up with some fancy electronics, and "automatic" things???
Get some good insulation, improve the box sealing, improve airflow around/thru the condenser, etc. (and figure out if your Frigobaot unit is working properly), and set it at about "5" or "6" (as needed), and it will last you another decade or more....(again, just my opinion!)

5. If the system was low on gas then I wouldn't expect to see such good evap temps. I don't think the evap could get much colder and the frost is
even.
Above, you describe the frost as uneven (1/4" to 1/2")???
But, yes...if it was even then yes the unit is getting cold...but..
But, 23* - 25*F temps for the evap plate/tub are not very cold at all!!
Now, it can all be that the little BD-35 is doing all it can (especially with its restricted airflow) and that your evap is getting as cold as it can get in the large (and poorly insulated) box that it is trying to cool??
But, until we see some more results (after improving airflow thru condenser and improving insulation and seals), I can be certain from this side of the computer!

Who's with me on this? Have I drawn the correct conclusions here or what?

Please have a look at my old article about my frig insulation improvements...
Frig/Freezer

EDIT:
I just saw where you mentioned the box size....
Only one box, about 4.8 cu ft....that's good...

As an example, my Adler Barbour BD-50 based system (air cooled) makes my one ~ 5 cu ft box a freezer with box temps of 6* to 8*F and spills-over to the adjacent ~ 4.5 - 5 cu ft box used as a frig, with frig box temps of 34* - 38*F....(don't know what my evap temp is, but suspect it's 0*F or below)

So, I suspect that if your BD-35 system is working okay (and you improve the airflow thru the condenser), and if you insulate the box better, you should be fine using the whole ~ 5 cu ft box as a frig, and be able to keep something frozen inside the bin...but...
But, I do hope that Rich (or Richard) chime in here, as I'm not sure what temp your evap should be at?? But, I do think it should be colder than 23* - 25*F!!

Fair winds..

John

chala · 12-10-2016, 11:15

QUOTE=BlackAdder;2233574]

Evaporator is ranging from 23-25°F (-4 - -5°C) depending on where I shoot.

Box is ranging from 48-57°F (9-14°C). So not really much better than before actually.

The evaporator is already covered with 1/4" of frost on the bottom and about 1/2" of what looks like ice on the top (within 24 hours remember).

Ambient temperature is 86°F (30°C).

4. I read on the forum about the STC1000 electronic thermostat. I think I'd like to get one so I can see the temperature at a glance to know the system is working and also apparently it can be programmed to do auto-defrosting once a week.
[/QUOTE]

You still have too much moisture inside the box. Remove the content and keep it cool inside an esky, you need to quickly defrost your evaporator, wipe all the moisture inside the box with a towel. Do not return moisture inside the box by allowing condensation to stay on the content from the esky, wipe everything dry before returning it into the box. Food that carries a lot of moisture should be kept in enclosed containers.
A cheap way of monitoring the temperature is to buy a weather station with an outside sensor and fit the sensor inside the box. These sensors are fairly resistant and can record fairly low temperature, can be wrapped in a plastic or fitted into a container. The station as the advantage of been able to memorise the highest and lowest temperature.
That evaporator of yours should be able reach much lower temperature.

Quote:

Originally Posted by senormechanico

We take out all the food, hit the plate with a 1650 watt hairdryer to defrost when it gets over 1/8" and can tell the difference in performance. We defrost the box about every week or ten days in the summer when we're on six weeks vacation. It takes less than ten minutes maximum from start to finish and saves amp hours overall.

Be carefull not to melt the box or start a fire.

ColdEH · 12-10-2016, 11:52

Evap temperature is directly connected to the amount of subcooling you have or basically the temperature of your condenser at the output and the volume of charge . Check the temperature of your inline filter drier with your laser temperature gun , That would help diagnose whats going on . Also more insulation !! If you can keep that cold in the box then your evap temperatures should fall in relationship to the box temperature .

Regards