Skips new Seafrost poor performance problem

[skipgundlach]

Originally Posted by Richard Kollmann

Skip, you may have to live with the 10 cubic ft refrigerated box and the system you have knowing the amp-hrs consumed at 60+ degrees will be increased by 100% in ambient conditions with air and water temperatures of 85 degrees F.

Ah, well...

Originally Posted by Richard Kollmann

I see only one design difference between BD50 and BD80 compressors you may not have considered as affecting overall performance. Very small systems powered by Danfoss BD compressors are designed to be cycled by thermostats controlling evaporator temperature not box temperature. Controlling evaporator temperature using a hysteresis differential of 10 to 18 degrees F will reduce tendency of compressor to over power evaporator.

Our system is set up to read and control by the plate temperature. SF's preset was 6.5 hysteresis. I'm attempting your freeze-down and have encountered a problem, below...

Originally Posted by Richard Kollmann

In an adequately insulated box with evaporator thermostat index number set to produce desired box temperature actual box temperature is held to Plus or Minus of one degree. Because you’re new systems refrigerant flow control is by a fixed low pressure regulator instead of a capillary tube or expansion valve balance between compressor output and evaporator efficiency is important.

Originally Posted by Richard Kollmann

I'm not sure what this means in real life aboard. Our prior system measured box temps and kept it well in a 2 degree range. With the system as it's set up, indicated (from the box, not plate probe) temps vary over 10 degrees between off/on.

Originally Posted by Richard Kollmann

The major difference between the BD50 and BD80 is in controlling speed of compressor and how speed change effects performance especially amp-hours consumed. Danfoss BD80 AEO speed controller module increases or decreases systems COP performance bases on thermostat’s controlling action. If compressor does not cycle off in a given running time its speed is increases this means if thermostat is going by box temperature compressor will never operate at its most efficient speed. With Frigoboat’s speed controller the BD50 may not have had enough capacity to overpower evaporator.

I've been trying to find which of the Carel thermostats is used in the Sea Frost speed controller, to no avail.

An anomaly has arisen in my attempting to find equilibrium.

First, it's cycling, despite my initial setting of -21 plate temp. I raised that to 19 to see if there is any change in a reading I can find no info on, nor get to go away despite running through the setup instructions provided with my controller many times, now.

The display shows a what-looks-to-be-an "n" followed by a zero or "oh" reading. Nothing I have done will make that go away.

My reefer crept upwards to it's just now cycling; it's reaching its temp quickly, as is usually the case, especially if the rise has been heat gain vs any door openings or loadings. It usually takes less than 10 minutes to reach the setpoint (34 to 32 degrees indicated by the reefer probe). Recall that controller to also be a Carel, but single probe, unit.

So, I have no confidence that our test is happening; surely my plate has not dropped more than 20 degrees since I started, and a quickie thermo showed the plates at about zero. In the time I've been typing, the reefer has reached its shutoff point. If the box were truly freezing, the reefer would more than keep up with ambient vs fan propelled air, and in fact, should drop well under my setpoint, based on prior experience with the FB unit.

What do I need to know about the "n0" reading? SeaFrost instructions have no comment (nor indication that it exists, even) on that display item...

Yikes.

L8R

Skip

[Richard Kollmann]

Skip, I stay away from these electronic troublesome units. Carel or $15 look a like models on EBay all can have modified operating systems that makes them difficult to manage. I do receive requests from boat’s needing advice when these electronic thermostats fail. I am sorry to say my advice is to disconnect electronic thermostats from Danfoss module C and T terminals then install a jumper so refrigeration unit can operate until they can contact manufacturer for information on how to re boot program processor. Last week a snowbird boater spending winter in Bahamas with a non functioning BD80 compressor did remove what sounded like a Carel and installed a manual off on switch across AEO thermostat module terminals. If this bypass method is done on a BD35 or BD50, compressor will only run at minimum 2000 RPM while BD80 with AEO module controlling speeds will still be accomplished by AEO function to find best energy efficiency.

[SV THIRD DAY]

Originally Posted by Richard Kollmann

If this bypass method is done on a BD35 or BD50, compressor will only run at minimum 2000 RPM while BD80 with AEO module controlling speeds will still be accomplished by AEO function to find best energy efficiency.

Richard of course knows this, but for the benefit of others, the BD50 and BD35 compressors can also be set at various speeds from 2000 to 3500RPM by placing the appropriate sized resister in the thermostat circuit or in your temporary bypass. The resister sizes and corresponding speeds can be found easily on the electronic controller spec sheet. I don't have them memorized and I'm flying out to the boat show">Miami boat show at the moment zipping through the airport.

[skipgundlach]

Follow-on question on re-reading:

Originally Posted by Richard Kollmann

clip....

Very small systems powered by Danfoss BD compressors are designed to be cycled by thermostats controlling evaporator temperature not box temperature.

So far, so good, despite Frigoboat somehow making measurement of the box the determinant for on/off work...

Originally Posted by Richard Kollmann

Controlling evaporator temperature using a

Originally Posted by Richard Kollmann

hysteresis differential of 10 to 18 degrees F will reduce tendency of compressor to over power evaporator. In an adequately insulated box with evaporator thermostat index number set to produce desired box temperature actual box temperature is held to Plus or Minus of one degree.

If I understand the above correctly, if I make my hysteresis somewhere between 10 and 18 degrees (probably trial and error to determine the best level), I should be able to set my cutoff point to the desired box temperature, and the box will stay at that cutoff temperature while the plates somehow gain that differential, and then recool as the compressor is restarted, also without lowering the box temperature?

But to have our factory specified 6 degree differential somehow allows the box temperature to vary by over 10 degrees between shutoff and restart?

I'm having some difficulty wrapping my brain around that one.

Originally Posted by Richard Kollmann

Because you’re new systems refrigerant flow control is by a fixed low pressure regulator instead of a capillary tube or expansion valve balance between compressor output and evaporator efficiency is important.

Originally Posted by Richard Kollmann

The major difference between the BD50 and BD80 is in controlling speed of compressor and how speed change effects performance especially amp-hours consumed. Danfoss BD80 AEO speed controller module increases or decreases systems COP performance bases on thermostat’s controlling action. If compressor does not cycle off in a given running time its speed is increases this means if thermostat is going by box temperature compressor will never operate at its most efficient speed. With Frigoboat’s speed controller the BD50 may not have had enough capacity to overpower evaporator.

Ah. So, I may be overpowering the evaporator(s)?

Meanwhile, I've been running the system on "low" vs "automatic. I presume this means that however long it takes to reach the shutoff temperature, it will continue to run at that speed, and the same would be true at any other fixed speed (low, medium, high - the other two settings are "off" and "automatic").


Added info from yesterday: As I wasn't seeing constant running, I reset the shutoff point to where I had it previously. Before that time, the controller lights and stability of the reefer side suggested that it was continuing to cycle as it had before (despite my having drastically lowered the setpoint).

And, now that those setpoints have been restored (5.5 with 6.5 hysteresis), while the "nO" continues to be a constant, where it was previously the box temperature, the same behavior continues; it cycles on and off, and the reefer maintains a mostly stable (turning on very briefly when 34 is reached after a long creep upward) temp, neither struggling to stay cold, nor the freezer dropping so far that the reefer never runs (convective spillover, as was the case sometimes in the Bahamas with the Frigoboat system).

I conclude (without hearing, yet, nor even having a "read receipt", from Cleave at Sea Frost) that the display indicates that the controller isn't seeing a box probe. I did nothing which should have had that effect (no mucking about near either the controller or the probe itself during my setup of the much lower trigger temp), but given the performance, it seems reasonable for that conclusion.

Just why it never actually headed south when I radically increased the call for cold by setting it to -20 is beyond me, too, however, so I remain a naif in all things refrigeration.

Thanks for any other insights.

L8R

Skip

[Richard Kollmann]

Skip, I am sure that all who have followed this thread and the previous Frigoboat failure do understand your frustration. Troubleshooting a one of a kind system is difficult, especially when Danfoss basic design components are not used.

Your rambling on with minutia that is not relative when asked for specific facts this may be why you lead others into your rambling unproductive word threads. Look back at how you and Frigoboat ignored the basic indicators, I gave you, high amperage, high compressor temperatures and pressures way out of normal control for 134a refrigerant limits in refrigeration, If these abnormal conditions are not corrected when first found will cause a complete system failure. And after spending months and big dollars complete system replaced.

Troubleshooting is a process of elimination so look at what we know or at least believe to be facts about your new SeaFrost unit:

• At this point in time it appears the box insulation is not the major problem.
• Refrigerant capacity and evaporator plates performance reported earlier indicates plate and line temperatures indicate refrigerant and plates are performing correctly.
• Still there is a question why pumped water is a better performer than Seafrost’ extra large fan cooled condenser. Both condensers have a optimum ambient temperature range. These condenser temperatures do change efficiency but if complete system is in cool water and cool air as report and still will not satisfy desired box temperature I would not worry about condenser cooling at this time.

I think items 1 2 3 cover what appears to be a good system and must be pointing to electrical control over system as your trouble. Lack of box desired temperature and unbalancing compressor output to match evaporator capacity is all that is left. The BD80 was not intended to be coupled to a electronic thermostat that might influence the milliamp current flow between module terminals C and T. Bypassing electronic thermostat will allow box temperature to reach refrigeration units lowest temperature.

[colemj]

Richard,

It seems like you have a negative opinion on electronic thermostats, and I would like to hear more about it.

We have electronic thermostats controlling our AB BD50 system - one controlling the spillover fan and the other controlling the compressor.

These seem to work perfectly fine. Frankly, I don't see why they are any different than the non-electronic ones. All they seem to be is a temperature sensor that snaps a contact open and closed at preset points. I can hear them actually "snap" on and off.

Other than that, their only other function is to tell me at a glance what the box temperature is in the position of the temperature sensor - which on our system seems to correlate well with the whole box temperature.

So what makes these less optimum than the normal little dial wheel with numbers on it?

Mark

[skipgundlach]

Some real-life updates...


So, we have a chock-a-block freezer, a pretty full reefer, and are in the Bahamas. Our water intake is no longer fouled, and we have full water flow.

Air and water is in the low 80s. Sun and wind are in good supply, though not dependably for either.

When it's blowing like it usually does (10-15) and high sun (not appreciably higher than Vero Beach, as we're very similar latitudes, but it's spring, now), our batteries actually catch up during the day. A week of no rain and a good breeze would keep us nicely topped, recovering from overnight. ...

... Where we eat about 70-80 amp hours when it's calm, as our system is working just beautifully, all around - by running on High, with water cooling as well as the air.

I've not bothered to sit and count/measure all the on-off points, but the reefer and freezer seem to alternate. When the freezer's gotten down to temps, the reefer's about ready to call for more cold. Just about the time the reefer gets down, the freezer gets up. As, historically, the reefer (spillover blower) was on about 15-20% of the time, and I see the freezer seems to be on more than it's off, I'm guessing, as well as counting the amps, that the freezer runs 75-85% of the time.

I don't recall if I specified that I lost any reading of the box temp in the freezer while trying Richard's request to overfreeze.

Several email contacts with Cleave identified the problem to be presumed needing resetting to some defaults. They, of course, don't provide the manual to the actual thermostat, instead editing out everything not directly related to making it set up like they want (KISS, a good thing, usually). His last email, just before I left the states, offered to have me call his secretary who would walk me through the steps necessary to regain my box temperature. Good on him for the followup. But I'm living with the "n0" display, as, if the box is cycling, and there's frost on the line out to the bulkhead, but not all the way there, it seems to be working.

I did drop the cycle temp by a couple of degrees over two tries, to balance the reefer better. It was running continuously, not helped by the major motoring we had to do, with the ER bulkhead being one side. However, the biggest impediment, literally, was that I'd stuffed the spillover top (we have a 1" gap over the spillover barrier, which works out to the same square inches as the fan) with a rag; in the Frigoboat days, we had to do that to prevent the reefer from freezing - that is, the air exchanged, even on convection, was so cold that it sometimes froze stuff.

No such problems, here, or, at least, not before I put the cycle temp down a great deal lower than the 2.5 I now have it (6° hysteresis) - at, of course, the cost of many more dead electrons...

So, I was just spoiled. When there's plenty of electrons, it's just fine. My objection has been to the comparative cost of operation.

I, too, by the way, would like to know of the reasons for opposition to electronic thermostats. Mine have performed admirably, albeit I really still don't get why we want to monitor the plate temperature, at a very wide hysteresis, compared to monitoring the box at a 2° hysteresis as was the case with the Frigoboat.

L8R

Skip

[Richard Kollmann]

Skip, you are now in April boating in 80 degree Bahamas temperatures with compressor running 75% to 85% of the time. In another couple months in Bahamas you can expect your BD80 compressor to run 95% to 105% of the time and you may not be able to maintain the your desired box temperatures. The SeaFrost BD80 compressor is 30% larger than previous Frigoboat’s BD50 compressor and SeaFrost’s seawater condenser is far more efficient in warm water than frigoboat’s keel cooler. If your insulation test was correct why is this present system so far out of balanced performance?

There are NO two boat or ice box conversions the same. With most icebox conversion refrigeration unit designs in the past no after installation performance balancing of components was required. With over 100 equipment options to select from when system is to be powered by a new variable speed Danfoss BD compressor final performance balancing of all components is left up to the person installing it.

• A refrigeration system is in balance when compressor output is equal to the evaporators ability to except and transfer energy produced. Your earlier reports would indicate poor condenser cooling suggesting excessive compressor RPM or restricted refrigerant flow.
• Your SeaFrost unit unlike any other ice box conversion unit has a fixed evaporator suction pressure regulator instead of a TXV or Capillary tube. This pressure regulator is preset by system manufacture to what they believe will compensate for pressure loses with your number of evaporators and tubing lines. Final adjustment of pressure regulator is generally done by checking supper heat through all evaporator coils. If pressure regulator is set too high temperature will drop faster but reach a much higher temperature equilibrium preventing box from reaching desired box temperature. Setting pressure regulator too low will take much more running time but equilibrium may be as low as -20 degrees F.
• If a thermostat regulates box temperature with a standard evaporator instead of evaporator, temperature reading point can unbalance high side liquid pressure increasing daily power consumption.
• I have ask this question before, does this system have a liquid receiver to compensate for refrigerant flow and temperature volume changes?

Advising you on Adjusting your refrigeration system is like trying to level a six legged table by shortening one leg at a time. Your best hope is to follow SeaFrost’s advice. The reports I have seen form others with this system have been happy with SeaFrost.

[skipgundlach]

I believe it does.

Or, at least, there's a sizable canister with a sight glass in it. I've asked about the character of that (constant bubbles, and when not, visible liquid below) as to sufficiency of charge previously. There's also a large filter-dryer in line.

The cost in electrons currently, and when we were in mid-to-high 90s Vero Beach water and air, are the only real gripe I have.

Today, with a breeze and sun, my sun and wind system are not only keeping up with the load of the reefer and two computers, but replacing amps lost overnight - which were less than typical, because the wind started around midnight.

I have not had any success in measuring equilibrium, but I CAN say that this morning, with the compressor satisfied (plate temp reached), the reefer side dipped very briefly below it's satisfaction point, by 0.1 degree - and then began its usual slow slide to the turn-on point 2 degrees away. That tells me that the freezer is cold enough to satisfy my draw on a convective basis (well, it's what it tells ME - it may well tell you something else), and, at least based on where the ice is, having an appropriate setting for the pressure regulator. Recall that Cleave's only suggestion(s) for my system was to play with the regulator (I did, and apparently have found the sweet spot) AND get another entire reefer system.

Frigoboat Info (Rob, the US distributor) worked valiantly with me to solve our issues with the FB. Ultimately, he referred me to Clay Hansen as the ultimate reefer guy for resolution and, when that failed, installation of a replacement. I =have= followed SeaFrost's advice - other than the second $4K system, which is simply out of reach for us, what with family obligations sucking up all current income and any reserves having been previously dispensed in the same direction. But I wander...

That Clay took 6 weeks, including having to add water cooling, to get it right, if the recommendation was well-founded (presuming that he was a reefer savant), suggests to me that there must have been some issues with the system as it was installed. Whether or not those issues have resolved since then by our tweaking I can't say.

However, time will tell if your assessment of what we'll face is correct, as we'll be here all summer. The major reason for that is to avoid the Vero Beach summer, which is brutal, not to mention the intake for the water cooling fouling so severely that it has to be removed and reamed weekly...

Thanks for your interest.

L8R

Skip

[skipgundlach]

Update...

At the SSCA annual meeting, I was able to consult with Bob Williams, Nigel Calder and Rich Boren (Technautics/Cool Blue/RO water) along with a couple of knowledgeable but not industry-involved folks.

The consensus was that there should be no reason whatsoever for the amperage I'm using, particularly in light of all that precedes in this thread. Indeed, in other conversations elsewhere online, many do report mere fractions of the kind of amps I've seen for similar installations.

Rich Boren thought it important to get gauges on the system to see what was 'real' about the system.

So, I called Cleave to discuss that. At that point the system had been offline and open as we'd been off the boat for a couple of months, so it would start from scratch.

He suggested that I first disable and block my spillover to take the refrigerator out of the equation, and then run the freezer, empty, to see what happened.

I did that, on air only (as that's the comparison point that everyone who had such markedly better results than I had used) and after the first couple of days needed to bring the system down, it started cycling. I used the automatic setting rather than my previous mucking around with constant speeds as Cleave had suggested, due to presumed overhead from the computer part of the automated setting.

The system cycled at close to their expected 32/12 minute on/off, and was stable. I measured, as I have from the beginning, our amp draw by seeing the difference in cumulative amp hours deficit overnight in calm conditions, taking the wind and solar out of the equation.

Surprise - it was markedly lower than the typical 10A I'd seen. Hm. So, I added water bottles - about 10 OJ 59oz type - and let it stabilize again. Same story, essentially. The refrigerator was keeping a pretty steady high-40s, and the freezer was cycling at 16.5-18.5.

So, I went to lower the cutoff temp and found that I had mistakenly thought it was +5; it was +1.5. So, I set it down to -2 (still 6 hysteresis).

Freezer dropped not at all - still 16.5/18.5. But overnight usage was still average 5A. Drop the setpoint to -5. Now down to 15.3/17.3. Isn't that interesting! The box differential is 2 degrees - and would prove to be so throughout my testing. That's what the Frigoboat, which didn't use plate temperature, was set for. However, I'd set the FB for 8/10; this was a long way from that - but also much less amp draw than we'd been experiencing earlier in this thread. OTOH, I believe Clay Hansen erred in putting the probe halfway between the fan and the spillover slot; it had been halfway down the divider, halfway between the fan and the plate. That location measures colder than where it is now; it's not really important, so long as stuff stays frozen. Back to the testing...

Hokay. No reefer, no gain (well, much less) - it was still keeping 48-49 with the spillover blocked (though, I'm sure, not entirely - and, intentionally, the divider isn't very high R value). Cycle times were about 31/16, or about 60% run time, and draw continued to be ~5A average.

So, after several more days of that, I dropped the setpoint to -7.5 at which point the temps dropped to 14.0/16.0. However, measured plate and water bottle temps were -4/-9/-11 and -4/-3/-2, respectively (the rest of the water bottles were under a shelf). Frost continued to be just perfect, with all three plates and - up to 1/2" from the exit, but not beyond - the return line frosting.

At that point, I uncovered the spillover fan, but didn't energize it (I have a NO/NC reed switch I use to control the fans and lights in the reefer; open the door and the fans go off and light comes on; the circulating fan is on a constant circuit, but the spillover fan isn't energized unless the thermostat calls for it). Freezer temps continued 14/16, but the reefer moved down from the high 40s to a very constant 42.3. Amp draw continued at about 5 on average.

Hokay! Things are looking up. Still air only, moderate temps (80s/low 70s). What happens when I repower the spillover fan, but leave the return stuffed (dramatically lowering the air transfer)? It moved into - slowly - its norm of 32/34. Freezer continued to cycle normally, almost exactly to factory spec, at 32/13 or so (some variance but not enough to make a difference). Overnight average, however, moved up to 7A.

As temperatures cooled a bit outside, so did the amp draw; mostly, for many days, I was seeing 6-7A average overnight in calm conditions. When it was breezy, there was a notable contribution, and during the day, sometimes when we'd be off the boat, we actually gained amp-hours due to both the sun and wind working.

I also minimally loaded up the reefer (beer and coke and a couple of minor comestibles needing to stay cold); it cycled as usual, but with very short run times and long off times.

Shortening what has been a very long (nearly 2 months of constant measuring), and a drop to -10 for the cutoff, with appropriate readings of plates and water bottles' temps, there was only a single anomaly. That was when we took a couple of old ladies for a ride to nowhere, down and back to Ft. Pierce, which involved motoring the entire way.

From the time we started, until more than two days later, the freezer never shut off. I could understand it running continuously during our motoring, as the ER was probably close to 100F - but it had cooled completely overnight, let alone 36 hours later. The air was in the high 70s/low 80s, and ~70 overnight. If that little amount of difference (a kick from the engine heat for 4-5 hours, and then being open entirely and cooled to ambient by the end of the day) can cause it to run continuously, I can imagine what happens when the ambient air is 90+ and the water we're in is similar, regardless of whether we're sucking the extra amp from the pump - the air cooling can't keep up, and the water adds that extra amp of draw.

During that time, we were seeing overnight averages closer to 10A, what we'd experienced in the summer in Vero, and to a slightly lesser degree in the Bahamas, where we'd had to run the engine more than we'd have liked.

However, fast forward to current. I've moved the cutoff from -10 to -5, and the nights and days have been markedly cooler. At -5, and much cooler outside, it's been 11.7/13.8, and a typical overnight of 5A average; the reefer nearly never runs, as the passive spillover is sufficient to keep it in the low 32 dot something range.

If we had reliable sun and wind, the amount it's using would be of no issue. Just why it is that it seems everyone else - with air only - can manage on half those amps, or less, even, is beyond me, unless it's that the condensor is not big enough to carry away the heat effectively. It's ducted to the outside, but the cooling air is from the engine room. Cleave suggested against using the outside for input as it would have salt air and maybe spray in it, so the fan pushes from, rather than pulls to, the box (Sea Frost is a closed system in the air cooling; air all moves over the compressor as well.)

So, at the moment, I've again gone to -2 for a setpoint, as it's actually quite chilly for Vero - highs in the low 60s and overnight high 40s/low 50s. That has led to very short run times - mid-20s - with accompanying relatively long off times - low 20s. Initial on/off is staying about the same - 11.7/13.9, but that may slowly rise as the water bottles gain back those 3 degrees I raised the setpoint.

Absent conflicting information from gauges, I think I've got it tweaked about as far as it can go. The bottom line seems to be that if I were living in New England and spent my winters in Vero, and used water cooling (taking advantage of the cold waters up there) during the summer, I'd see results similar to what others have reported.

But, I'm not, and won't, so about all I think I can do at this point is figure out how to add a massive amount of solar to minimize the amount of time the Honda2000 has to run. When we have a breeze and clear skies, we mostly don't have to run it, and, that's really about the only issue here, as the system seems to work perfectly - but demands an exhorbitant wage.

L8R

Skip, leaving for the Bahamas again ~February or late January if we can manage it

[Richard Kollmann]

Skip, you are your own worst enemy when it comes to your boat’s equipment and their maintenance. The number of sea test trials you must do confirms that decisions you make regarding equipment and maintenance are tell tail signs of a problem. Even though you look for advice to solve problems you fail to follow good advice by following a tangent theory of your own that in many cases prolonged a solution.

Refrigeration is but one of your mysterious mechanical boat troubles that started after a night cruise ending up on the rocks. For those of us who followed your technical experiences for the last 12 years from mutable alternator and belt failures to prop shafts to rudder posts we wonder why you have so much trouble. Other drawn out equipment repairs especially attempts to manage your onboard boat DC electrical power grid and electronics must has given venders working with you some frustrating times.

From the time before your accident when I met you at a SSCA Gam in Melbourne FL I have read all your logs and posts especially those about lifestyle on board and your choices with regards to refrigeration. With all of refrigeration troubles and conversations with Frigoboat on the first refrigeration unit and the present SeaFrost you must have wasted hundreds of dollars and many months of experimenting with make believe solutions. We now know that the Frigoboat system was not repairable at the end because of your and other Frigoboat keel cooler systems operated too long at excessive tropical temperatures.

You reported with regard to present new SeaFrost BD80 powered system you reported that “At the SSCA annual meeting, I was able to consult with Bob Williams, Nigel Calder and Rich Boren (Technautics/Cool Blue/RO water) along with a couple of knowledgeable but not industry-involved folks.” You have also discussed the Seafrost performance trouble with manufacture Cleave and mechanic who installed system. Did you follow the advice each of these knowledgeable people in looking for a solution? From the amount unrelated words to the problem in last post I guess you went off subject again ignoring their advice.

Bypassing Mickey Mouse thermostat control to see if problem is refrigeration system or excessive heat loss in surrounding box, what was the result? With thermostat bypassed at AEO module terminals compressor in 40 minutes will reach 4,500 rpm and remain there for as long as thermostat is bypassed. In 4 to 8 hours box temperature should reduce down to zero F. Now turn off compressor with every thing in freezer frozen and block off spillover openings.. If your 6 inches of box insulation is still holding a reasonable good R value product in freezer should stay frozen for 8 to 16 hours. As long as box temperature over time is good and as you reported earlier in this thread evaporator plate temperature tests indicated temperature of zero were recorded box insulation quality has decreased.

Both the Frigoboat keel cooler system and the SeaFrost BD80 system are unlike standard mobile ice box conversion refrigeration units. Frigoboat uses a under water condenser with no way to adjust condenser cooling medium temperatures. SeaFrost BD80 unit controls refrigerant flow by a low pressure constant pressure flow regulator valve instead of a fixed orifice long capillary tube. Because of these two systems differences to conventional systems it is easy to understand why 90% of the servicing personal and sales technicians are not able to handle performance trouble.

It is always easy to pinpoint a refrigeration performance problem although it is the corrective action that may require an experienced smart technician to re commission some of these oddly designed boat refrigeration units with their so called upgraded gadgets.

[colemj]

Skip, I've posted this before, but here goes again. Our system is a 4cf freezer spilling over to a 6cf reefer using a single thin evaporator plate in the freezer and a standard air cooled BD50 compressor. The boxes have 6" of 18yr old poured polyurethane foam. The freezer is kept at 10F and the fridge 34F - both with a 5F hysteresis.

I have a data logger on it, so I know how long and how much power it uses. Pulling the past two weeks of data operating in the Bahamas, the system averaged 48.6AH per day (and I have been putting a lot of fish and lobster in it, so it is working hard).

Your data suggests a system so far out of normal expectations that either something is terribly mismatched, the Seafrost system is pure junk, or your box is nowhere close to having the insulation quality you think it has.

You have a similar sized box as us that is ostensibly insulated the same, and more cooling capacity in your plates and compressor than we do.

In one of your previous posts, you were going to do a box insulation test exactly like Richard describes in his book. Did you do this?. I'm suspecting something wrong with the insulation because I don't understand how a BD80 cooling those holding plates can't bring the temp down and keep it there.

Mark

[colemj]

BTW your terminology is confusing. When you say it used 10A overnight, did you mean 10AH for that eight hour period, or 10A for each of the overnight hours (80AH)?. If it only used 10AH overnight, that seems pretty efficient.

Mark

[skipgundlach]

Hi, Richard, and anyone else who cares

I believe I did exactly what Cleave suggested, as (apparently poorly) described in my last. Admittedly, I did not (he didn't suggest it) do the pull the box to zero and disconnect (as my thermos are powered in the compressor circuit, I don't see a reliable means to see whether or not, or how fast, my freezer warms to not-freezing when it's off) routine you suggest.

However, based on my box temp (admittedly way off of what the probe says; see my last for comment about measured actual temps in the freezer when the system cycles off) rise in what period of time, I expect that it would meet your definition. My having (intentionally) a relatively low R value on the spillover barrier complicates that ability-to-calculate, but it seems that my time-between-cycles would meet your requirements by the time the box went from zero to 32. Note my comment that the passive spillover (included in that off-cycle time) is also cooling my reefer without any spillover fan help; from that I deduce (probably wrongly - I seem to be mistaken about nearly anything I think about this system or how things work in general) that if I were able to isolate - and insulate - the freezer to the same degree as the box as a whole, I'd easily fit your parameter for sound insulation.

Of interest (well, at least to me), when I returned to the boat last night, I again noted my AH deficit, and again when I got up this morning. I also noted the amp draw from 'nothing' (we have a variety of small maintenance loads which I subtracted when the freezer cycled again) to compressor running; it's pulling about 4A, which I expect is 'low' speed, now, when it's running. Indeed my overnight average was a little under 2.5A net. Even though I have, again (a couple of days ago, so it's stabilized on that level), raised my cycle (plate probe) temperature, now to -2, my freezer readings have not gone up, and the reefer continues to be supplied passively, keeping it in the neighborhood of 33F, no doubt helped by the small circulating fan which runs whenever the door's closed.

I agree that I'm thrashing about, but I believe I'm following Cleave's instructions as given. He wanted me to not put any gauges on until I'd done what I have described, so I have not, and all of this is with air cooling only.

Originally Posted by Richard Kollmann

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Both the Frigoboat keel cooler system and the SeaFrost BD80 system are unlike standard mobile ice box conversion refrigeration units. Frigoboat uses a under water condenser with no way to adjust condenser cooling medium temperatures. SeaFrost BD80 unit controls refrigerant flow by a low pressure constant pressure flow regulator valve instead of a fixed orifice long capillary tube. Because of these two systems differences to conventional systems it is easy to understand why 90% of the servicing personal and sales technicians are not able to handle performance trouble.

It is always easy to pinpoint a refrigeration performance problem although it is the corrective action that may require an experienced smart technician to re commission some of these oddly designed boat refrigeration units with their so called upgraded gadgets.

As to oddball systems, unfortunately, I made the presumption that I had been directed to someone who would either solve the FB basic issue, on which you've had a lot to say elsewhere (including that my failure duplicates hundreds of others you've documented), or install something which would work a treat. That this system, which you feel has an oddball setup, was installed is to my everlasting dismay.

But here I am, doing the best I can with what I have to work with - my admittedly feeble intellect and understanding - and feeling jealous of all those who seem to have markedly different results, but feeling as though we've got it about as good as it will get without gauges, and even that (measuring high and low pressures) might say it's right on. Indeed, albeit in relatively cool conditions, if I do, indeed, average 2.5A, that puts us in the 60AH/day load. That's entirely liveable - but we don't, and won't, live in this temperature range, for the most part.

But I'm probably wrong about that as well.

[skipgundlach]

Originally Posted by colemj

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In one of your previous posts, you were going to do a box insulation test exactly like Richard describes in his book. Did you do this?. I'm suspecting something wrong with the insulation because I don't understand how a BD80 cooling those holding plates can't bring the temp down and keep it there.

Mark

Hi, Mark, and thanks for the post. As to the one following, when I say X amps, I mean as a constant; e.g. 5A would represent 120AH/day.

Some time ago we did a delta test, measuring available surface temperatures, against nearby but not immediately adjacent surface temperatures. The average was about a degree; the highest was under 2 degrees difference from outside-the-box to opposing surfaces in the same plane, varying from 1.5' to 4'. At that time, aside from some very wonky questions about the validity of the readings based on surface makeup, the consensus (I'm probably wrong about that, too) seemed to be that sound insulation was indicated.

But I'm here to be schooled, or pointed to someone with the requisite skills to make a valid evaluation of our system. We're now, and will be for a few more weeks, and will be again, off and on for the foreseeable future, in Vero Beach FL.