Adding 507a to 404a-any problems?

[a64pilot]

Well one thing, the 101N0390 is the new AEO controller, which means it’s a soft start and starts at a lower RPM than it was last run at, then Ramps up speed.

However if you have a resistor in line with the thermostat, that overrides the soft start and low RPM start up and it starts at whatever RPM the resistor calls for, if its 1700 ohm, that is full speed which on a BD 80 is 4400 RPM. Trying to start at wide open if you will of course pulls more amps.
Either measure the resistance of the two thermostat wires or put a jumper between C and T terminals on the controller, this will enable AEO and soft start, or remove the resistor, but a jumper is easier, just a short piece of wire and two female spade connectors.
However your pressures not equalizing is puzzling, if the orifice were clogged, it would go stupid high immediately on start up, so why isn’t it bleeding off to equalize?

What gauge wire are your power wires and distance of run?

[TJ D]

Originally Posted by a64pilot

Well one thing, the 101N0390 is the new AEO controller, which means it’s a soft start and starts at a lower RPM than it was last run at, then Ramps up speed.

However if you have a resistor in line with the thermostat, that overrides the soft start and low RPM start up and it starts at whatever RPM the resistor calls for, if its 1700 ohm, that is full speed which on a BD 80 is 4400 RPM. Trying to start at wide open if you will of course pulls more amps.
Either measure the resistance of the two thermostat wires or put a jumper between C and T terminals on the controller, this will enable AEO and soft start, or remove the resistor, but a jumper is easier, just a short piece of wire and two female spade connectors.
However your pressures not equalizing is puzzling, if the orifice were clogged, it would go stupid high immediately on start up, so why isn’t it bleeding off to equalize?

What gauge wire are your power wires and distance of run?

We'll start with wire-we're running 6awg, about 20 feet. Voltage drop (at the controller) with both systems running is .4v. I'm really pretty confident that we've got good power. 100%, actually.



Right now, after being off for 1.5 hours, I have a 140psi pressure differential. Pete says that 75 is enough to cause this error, and it seems that he's leaning toward the valve on the evaporator-it closes with the low side pressure increase on shutdown, if I'm understanding correctly.



I'm not sure if you followed the whole saga, but we replaced a failed 134a unit with a 404a unit, both from Seafrost. They said that it was a very simple swap, just turn the expansion valve and set it to 15psi-all done.



It's possible that this is the problem. I'm a little over my head at this point, frankly.



The thing works great when it finally does decide to start-The most sensible thing to my amateur's mind is the pressure differential as the reason for not starting up.



It's never really worked right since install, but it's been cold enough that we really haven't dug into it.



I only recently really put some demands on it when we stuck the dog in there (the box was empty) on a wickedly hot day, and he discovered that it's an absolutely fantastic place to spend a few minutes once an hour or so.



Yes, I put our dog in the freezer, you read that right. I've never seen him so happy, honestly. The lid, of course, needed to be open for all these operations, and with the cabin pushing 100 degrees, it really warmed up the box.



Anyway, the upshot is that this problem really presented itself, so there are 2 upsides. Mostly just 1 upside for Baxter, unless I get it working right, though.

[a64pilot]

6 Ga at that run is good, I’m 6 Ga with about a run of 20 ft one way.

The differential pressure is way off, there shouldn’t be much at all after a few min after shutdown, it should equalize, and now of course it’s trying to start under a high load, exceeding start up amps and shutting down.
Compressor and module are working as they should, I believe.
The TXV, has to be out of adjustment, since it’s adjustable I’m assuming a TXV, cause of course a cap tube isn’t adjustable.

Opinion of mine of course, I’m licensed, but do not have much experience and pretty much zero on this small stuff.

Pete was hitting around slugging earlier, which of course will cause stupid high initial pressures as it tries to compress a liquid, home system compressors are often heated to prevent slugging.
But with your pressures not equalizing, you have found your problem.
In my opinion. I’d open up the TXV, unfortunately I don’t know the numbers to look for, I have no experience with that refrigerant, but the numbers should be available.
I would not mess with the charge

[TJ D]

And, finally-


After 2 hours off, pressures were 53/153. I disconnected the HP gauge, which probably dropped the HP pressure a little further, and the compressor fired right up.



It's 1AM here in Spain, and I've had enough. Time for bed.



Thanks for all the help guys. Hopefully I wake up to a CF revelation and a workable course of action.



This kind of thing really is the best of this forum. I do tire of the 'can I cruise around the world on $4000' threads, but the practical support that is freely shared here makes this place well worth visiting.



TJ

[TJ D]

Originally Posted by a64pilot

6 Ga at that run is good, I’m 6 Ga with about a run of 20 ft one way.

The differential pressure is way off, there shouldn’t be much at all after a few min after shutdown, it should equalize, and now of course it’s trying to start under a high load, exceeding start up amps and shutting down.
Compressor and module are working as they should, I believe.
The TXV, has to be out of adjustment, since it’s adjustable I’m assuming a TXV, cause of course a cap tube isn’t adjustable.

Opinion of mine of course, I’m licensed, but do not have much experience and pretty much zero on this small stuff.

Pete was hitting around slugging earlier, which of course will cause stupid high initial pressures as it tries to compress a liquid, home system compressors are often heated to prevent slugging.
But with your pressures not equalizing, you have found your problem.
In my opinion. I’d open up the TXV, unfortunately I don’t know the numbers to look for, I have no experience with that refrigerant, but the numbers should be available.
I would not mess with the charge

I'm not sure that this is a TXV valve. Pete called it something else. I did make a note of the setting and give it a couple of full turns in each direction with the unit off, and there was no change on either gauge.



So, I'm sort of at a loss now. We're just heading to the Canary islands shortly, and then will stick around there until the end of the hurricane season, so if I can get this thing diagnosed, there should be enough time to get it sorted before the transat and our Caribbean season. I can nurse it along for a while, anyway, and should be able to get parts shipped in to the islands-assuming we can diagnose it!



Anyway, I'm off to bed now. Thanks again.

[Richard Kollmann]

Jt, Your constant pressure or automatic expansion valve responds to outlet pressure. It meters liquid refrigerant to the evaporator, maintaining a constant evaporator pressure AXV unlike TXV and Cap Tubes. It is also not a crank case regulator.

You have indicated the system was new for a few weeks. How long did it operate normally before it first sent trouble code flashes. If unit run correctly for two weeks the question then is what happened to cause this overload start problem now?

What size compressor was on the Glacier Bay plates before and were these plates spider evaporates with a 1/2 inch OD refrigerant feed tube?

Now that you have decreased refrigerant flow pressure from 14 to 9 psi, is there any change in false start problem?

Bypassing thermostat and speed controller if there was one eliminated them as the problem.

Running unit on another module eliminated bad module.

Checking security of ground wiring eliminated three phase compressor pulse confusion triggering maybe 3,4,5,or 6 LED flash codes.

A single LED flash code every 4 seconds indicates faulty boat wiring that can only be determined by running jumper wires direct from battery to module.

A cooling fan or any amp load exceeding 1/2 amp on module terminal F will trigger a two flash LED code.

It should be understand that the chip in module has only one memory which is the first one seen. Additional fault codes will mask over first code. The code that will mask over others is a quick restart attempt. Before believing any LED code turn power off and watch for first code flash.

When there is a one of a kind design as this one is eliminating causes with a shotgun approach is the only way.

I always avoid removing any refrigerant to correct an overload condition if it is a blended refrigerant because the highest pressure component will come out first changing refrigerant's performance.

The AXV valve I do not think is the problem but I never use them because they are adjusted the same way you prevent a four legged table that rock back and forth. Shorten one leg and see what happens. I like smart refrigerant flow controls like Cap Tubes or TXV"s they both automatically change evaporator Superheat when conditions change.

[OzePete]

Originally Posted by TJ D

And, after 50 minutes of being powered off, the pressures read 41 and 190 between the 2 sides. I take it this is getting to the root of the problem.



Now, the question is what to do about it.



Cleave's on vacation for a couple weeks so I can't get anything out of him-I'm guessing based on Pete's comment about the expansion valve that this thing may be unsuitable for the higher pressures of 404?

Good morning / evening TJ,

That confirms the problem as being far too great a difference in pressure at the compressor for it to start.

This compressor has a soft start module which has far more chance of starting under load than the old DOL type, so leave that as is.

The issue is to balance out the compressors pressures while off.
There are no other issues causing this problem, but now what to do about it!

Firstly is the BD80 R404a compatible? Check on compressor ID plate.
Next, is there a valve after the evaporator(s) and before the suction line?
Next, is the evaporator fed via a capillary tube or TX valve? (Prior to evap)

If you could post pictures of the valve(s) or capillary on the evaporator(s), specially any label details, that would help greatly and I'm sure we can come up with a solution.

Cheers OzePete

[Richard Kollmann]

I have never seen one of these low pressure regulators used with refrigerants other than R12 and 134a. It is obvious that differential pressure many minutes after compressor stops is not being equalized by valves spring pressure that opening orifice. You might try adjusting spring in raising low pressure to 25 or 30 psi and see if this will help to equalize off cycle pressure. To permanently correct this problem you need a Thermostatic Expansion Valve with a maximum orifice Btu capacity that matches Compressor output.

You did not report back on lowering low pressure to 9 psi that I assume would have made conditions worse.

[OzePete]

Originally Posted by Richard Kollmann

I have never seen one of these low pressure regulators used with refrigerants other than R12 and 134a. It is obvious that differential pressure many minutes after compressor stops is not being equalized by valves spring pressure that opening orifice. You might try adjusting spring in raising low pressure to 25 or 30 psi and see if this will help to equalize off cycle pressure. To permanently correct this problem you need a Thermostatic Expansion Valve with a maximum orifice Btu capacity that matches Compressor output.

You did not report back on lowering low pressure to 9 psi that I assume would have made conditions worse.

I agree it would be unusual to have a crank case regulator on one of these micro system but the reports of pressures after stopping indicates that one exists or some other device equally inappropriate for such a system. (Besides this system appears to have had variations added to it, so who knows. That is why I requested TJ to post pictures, so lets see what that reveals.)

Otherwise why is the suction remaining so low after stopping when there would be plenty of liquid refrigerant in the evaps to boil off and increase the suction pressure unless that low side line is restricted after system stops, but by what if not a CPR?

At least it is now established that my diagnosis of excessive pressure differential in the compressor is the cause of start failure, so we can all forget about other hypothesis! TGFT!

Cheers OzePete

[TJ D]

Gentlemen,

There seems to be a little confusion here about the equipment aboard, so let's begin there.



First, there is nothing left from the GB system besides the thermostats. Everything single other component was supplied by Seafrost, professionally installed in 2016.



We have 2 completely separate units. The reefer is a BDXP, 134a. Works great.



The freezer was originally identical to the reefer, BDXP 134a, but with 2 evaporator plates instead of one. Otherwise, just the same.



In March, the freezer failed. It was the 3 flash warning. We quickly diagnosed a failed module and rather than replacing the 134a, we swapped the unit for a 404a. We just swapped the compressor/controller box out, no changes at the evaporator, except for turning up the expansion valve to 15psi.



With this setup, I was able to keep the box at 15f, and that was fine. I really didn't think about it again, so this startup error could very well have been happening all along-it does start up eventually, and it's a pretty well insulated box, so we were (are) getting by.



I first noticed the 3 flashes about a week ago, at anchor. It eventually started, and we were making a passage from Sardinia to Spain the next day, so I didn't do much with it.



Then I increased the load on things with the Baxter cooling episode a few days ago, and I noticed that the thermostat had been calling for action for a long time, with nothing happening.



This is when the digging began in earnest.



Pics shortly.

[TJ D]

Originally Posted by Richard Kollmann

I have never seen one of these low pressure regulators used with refrigerants other than R12 and 134a. It is obvious that differential pressure many minutes after compressor stops is not being equalized by valves spring pressure that opening orifice. You might try adjusting spring in raising low pressure to 25 or 30 psi and see if this will help to equalize off cycle pressure. To permanently correct this problem you need a Thermostatic Expansion Valve with a maximum orifice Btu capacity that matches Compressor output.

You did not report back on lowering low pressure to 9 psi that I assume would have made conditions worse.

I think that you guys are both pointing to the same thing, and it makes sense to me.



This valve was part of a 134a system, and we put 404a to it. I'm guessing that Seafrost just missed it when they sold me the new unit-they said to increase pressure to 15psi, but may have overlooked the pressure differential when off.



Dropping the pressure to 9 (and then 6) made the evaporators quite a bit colder. but I don't have data on how long it refuses to start up at the different settings at this point. Too long, anyway.

[OzePete]

It appears that the issue you had before (r134a system) and now with the (r404 system) are the same, a failure for the system to somewhat balance out the suction and discharge pressures making it difficult for the compressor to start.
Once we see the pics and can identify how the refrigerant flow is controlled and identify the culprit, it will be easy to suggest a remedy.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[TJ D]

Originally Posted by OzePete

Good morning / evening TJ,

That confirms the problem as being far too great a difference in pressure at the compressor for it to start.

This compressor has a soft start module which has far more chance of starting under load than the old DOL type, so leave that as is.

The issue is to balance out the compressors pressures while off.
There are no other issues causing this problem, but now what to do about it!

Firstly is the BD80 R404a compatible? Check on compressor ID plate.
Next, is there a valve after the evaporator(s) and before the suction line?
Next, is the evaporator fed via a capillary tube or TX valve? (Prior to evap)

If you could post pictures of the valve(s) or capillary on the evaporator(s), specially any label details, that would help greatly and I'm sure we can come up with a solution.

Cheers OzePete

To your questions-the compressor was brand new, built specifically for and shipped with 404a. i was just guessing as to the number, but this thing came from Seafrost just as it's installed.



There is a valve after the second evaporator. The 1/8" suction line comes off this.



Pictures attached. Pic one is the first evap in the series, followed by #2, with a shot of the valve.



The valve number is: 40PSIG 040054-01 08416

[TJ D]

Originally Posted by OzePete

It appears that the issue you had before (r134a system) and now with the (r404 system) are the same, a failure for the system to somewhat balance out the suction and discharge pressures making it difficult for the compressor to start.
Once we see the pics and can identify how the refrigerant flow is controlled and identify the culprit, it will be easy to suggest a remedy.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

I'm not sure about that theory. We had 3 flashes in both cases, but this one does eventually start. The 134a unit never ran again. I suspect that the module did in fact fail in that case. But, I had no interest in repairing it.



I had to drink my ice cream from a glass with that thing. It ran basically all the time, and it never got cold enough.



After a bunch of calls to SF, and Cleave finally told me that for long term storage of food, the FDA says 29 degrees is fine, and no matter what I did, I wasn't going to get the 134 unit cold enough for proper ice cream.



So, not wanting to repeat this frustration, I ordered the 404 unit. I had no interest in troubleshooting the old one.



Anyway, while the error code was the same, I do not think that they were in fact identical failures.

[OzePete]

That is a constant pressure valve not a TX valve. This thing regulates suction (evaporator) pressure and shuts down upon rise as suspected and this is why there is little / to no balancing of pressure. That is why the system will not balance out properley!

I don't know why such a device would be used on these systems but am sure that the same thing effected the R134a system also albeit the R134a compressor most likely had the old type DOL module which would cause it to be even more effected by imbalance of pressures.

A couple of other things..
1: Imbalanced pressure issues, when using a constant pressure valve, are increased as lower temperatures are sought.
2: Freezer temps quoted for R134a by SF are incorrect, minus 20C is easily achieved in fact we can get eutectic plates down to minus 25C using R134a and a properly engineered system!

Suggest you get the tech to remove the CP valve and fit an R404 TX valve or correct length (2.74Mt of 0.8mm ID) capillary tube, fit an 030 or 050 Sporlan flared filter dryer, evacuate, re-gas and run.

Good luck and Cheers.. OzePete

Also the skinny 1/8" pipe is the liquid line feeding the CP valve, not the suction.