New Thread on A54 fridge pumps (ATTN: OLIVER Vela Nautica)


Paul Dowd and Sharon Brown
 

Scott,

 

Thanks for the info. I’ll contact Oliver – I did meet him a couple of years ago in the Algarve and he certainly knows his stuff! Unfortunately we won’t be back on the boat in Grenada until later this year – Covid has certainly worked havoc with our place recently.

 

Cheers,

Paul

S/Y Ya Fohi - Amel 54 #98 - Grenada

 

From: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> On Behalf Of Scott SV Tengah
Sent: 19 March 2021 20:15
To: main@amelyachtowners.groups.io
Subject: Re: [AmelYachtOwners] New Thread on A54 fridge pumps (ATTN: OLIVER Vela Nautica)

 

Paul,

 

I was able to do it, so it can't be that hard :) 

 

It will take you a day to set up and requires a Windows computer to configure the software for the pump controller and interface between the Frigoboat interface and the pump controller. Point, click and load files. I would reach out to Oliver - he's a bit busy with a new child, but he will respond eventually. I can't speak for him, but I think he's intending on making a ready-to-install solution. That will probably make it easier to implement. I have no commercial interest in this nor do I want any.

 

I wanted to get it early because I "only" had a few remaining flojet pumps aboard. And being in the South Pacific and hearing about Garulfo waiting months to get a new pump, I wanted a better solution ASAP. If you do it yourself, you'll need to get a bracket made to mount the motor and pump head, but that was simple and cost me $20 - it's just a bent piece of aluminum. Aligning the motor to the pump head was the most difficult part, but I did it with a cordless hand drill and a dremel. I'm sure the metal shop could do that part for you, too.

 

 

 

 

 

 

On Fri, Mar 19, 2021 at 4:38 PM Paul Dowd and Sharon Brown <paul.dowd@...> wrote:

I would also be interested in getting this new pump. I haven’t followed this thread in derail but I do seem to recall that it was custom built, so would this be a problem for the “lay” owner?

 

Cheers,

Paul

S/Y Ya Fohi - Amel 54 #98 - Grenada

 

From: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> On Behalf Of Scott SV Tengah
Sent: 19 March 2021 18:55
To: main@amelyachtowners.groups.io
Subject: Re: [AmelYachtOwners] New Thread on A54 fridge pumps (ATTN: OLIVER Vela Nautica)

 

Hi all,

 

I cannot comment on longevity yet because I have not run the brushless for longer than six months, which was my average lifespan of the Amel Spec'd Flojets. Time will tell but so far the energy savings has continued and the freezer definitely is colder. Earlier I had to keep the freezer at MAX and now I have it set at 4-5 and more of the food stays frozen. Same climate (French Polynesia) and same amount of food in the freezer.

 

FYI I run the two galley fridges and the saloon freezer at all times.

 

On Fri, Mar 19, 2021 at 3:42 PM Courtney Gorman via groups.io <Itsfun1=aol.com@groups.io> wrote:

Yes wonderful Oliver and Scott I am very interested in the new pump.  Eagerly awaiting more details 

Cheers 🥂 

Well done 

Courtney 

Trippin 

54#101

 

On Mar 19, 2021, at 9:37 AM, Stefan Schaufert <mail@...> wrote:

Hello Oliver,

how long did these pumps last with you so far? 
How is it possible (for laypeople) to get these pumps (ready for use)?

Best regards
Stefan
A54 #119 Lady Charlyette, currently Exumas

 


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


--
Cheers
Paul
Ya Fohi - Amel 54 #98


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


--
Cheers
Paul
Ya Fohi - Amel 54 #98


Scott SV Tengah
 

Paul,

I was able to do it, so it can't be that hard :) 

It will take you a day to set up and requires a Windows computer to configure the software for the pump controller and interface between the Frigoboat interface and the pump controller. Point, click and load files. I would reach out to Oliver - he's a bit busy with a new child, but he will respond eventually. I can't speak for him, but I think he's intending on making a ready-to-install solution. That will probably make it easier to implement. I have no commercial interest in this nor do I want any.

I wanted to get it early because I "only" had a few remaining flojet pumps aboard. And being in the South Pacific and hearing about Garulfo waiting months to get a new pump, I wanted a better solution ASAP. If you do it yourself, you'll need to get a bracket made to mount the motor and pump head, but that was simple and cost me $20 - it's just a bent piece of aluminum. Aligning the motor to the pump head was the most difficult part, but I did it with a cordless hand drill and a dremel. I'm sure the metal shop could do that part for you, too.






On Fri, Mar 19, 2021 at 4:38 PM Paul Dowd and Sharon Brown <paul.dowd@...> wrote:

I would also be interested in getting this new pump. I haven’t followed this thread in derail but I do seem to recall that it was custom built, so would this be a problem for the “lay” owner?

 

Cheers,

Paul

S/Y Ya Fohi - Amel 54 #98 - Grenada

 

From: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> On Behalf Of Scott SV Tengah
Sent: 19 March 2021 18:55
To: main@amelyachtowners.groups.io
Subject: Re: [AmelYachtOwners] New Thread on A54 fridge pumps (ATTN: OLIVER Vela Nautica)

 

Hi all,

 

I cannot comment on longevity yet because I have not run the brushless for longer than six months, which was my average lifespan of the Amel Spec'd Flojets. Time will tell but so far the energy savings has continued and the freezer definitely is colder. Earlier I had to keep the freezer at MAX and now I have it set at 4-5 and more of the food stays frozen. Same climate (French Polynesia) and same amount of food in the freezer.

 

FYI I run the two galley fridges and the saloon freezer at all times.

 

On Fri, Mar 19, 2021 at 3:42 PM Courtney Gorman via groups.io <Itsfun1=aol.com@groups.io> wrote:

Yes wonderful Oliver and Scott I am very interested in the new pump.  Eagerly awaiting more details 

Cheers 🥂 

Well done 

Courtney 

Trippin 

54#101



On Mar 19, 2021, at 9:37 AM, Stefan Schaufert <mail@...> wrote:

Hello Oliver,

how long did these pumps last with you so far? 
How is it possible (for laypeople) to get these pumps (ready for use)?

Best regards
Stefan
A54 #119 Lady Charlyette, currently Exumas

 


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


--
Cheers
Paul
Ya Fohi - Amel 54 #98


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Paul Dowd and Sharon Brown
 

I would also be interested in getting this new pump. I haven’t followed this thread in derail but I do seem to recall that it was custom built, so would this be a problem for the “lay” owner?

 

Cheers,

Paul

S/Y Ya Fohi - Amel 54 #98 - Grenada

 

From: main@AmelYachtOwners.groups.io <main@AmelYachtOwners.groups.io> On Behalf Of Scott SV Tengah
Sent: 19 March 2021 18:55
To: main@amelyachtowners.groups.io
Subject: Re: [AmelYachtOwners] New Thread on A54 fridge pumps (ATTN: OLIVER Vela Nautica)

 

Hi all,

 

I cannot comment on longevity yet because I have not run the brushless for longer than six months, which was my average lifespan of the Amel Spec'd Flojets. Time will tell but so far the energy savings has continued and the freezer definitely is colder. Earlier I had to keep the freezer at MAX and now I have it set at 4-5 and more of the food stays frozen. Same climate (French Polynesia) and same amount of food in the freezer.

 

FYI I run the two galley fridges and the saloon freezer at all times.

 

On Fri, Mar 19, 2021 at 3:42 PM Courtney Gorman via groups.io <Itsfun1=aol.com@groups.io> wrote:

Yes wonderful Oliver and Scott I am very interested in the new pump.  Eagerly awaiting more details 

Cheers 🥂 

Well done 

Courtney 

Trippin 

54#101



On Mar 19, 2021, at 9:37 AM, Stefan Schaufert <mail@...> wrote:

Hello Oliver,

how long did these pumps last with you so far? 
How is it possible (for laypeople) to get these pumps (ready for use)?

Best regards
Stefan
A54 #119 Lady Charlyette, currently Exumas

 


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


--
Cheers
Paul
Ya Fohi - Amel 54 #98


Scott SV Tengah
 

Hi all,

I cannot comment on longevity yet because I have not run the brushless for longer than six months, which was my average lifespan of the Amel Spec'd Flojets. Time will tell but so far the energy savings has continued and the freezer definitely is colder. Earlier I had to keep the freezer at MAX and now I have it set at 4-5 and more of the food stays frozen. Same climate (French Polynesia) and same amount of food in the freezer.

FYI I run the two galley fridges and the saloon freezer at all times.

On Fri, Mar 19, 2021 at 3:42 PM Courtney Gorman via groups.io <Itsfun1=aol.com@groups.io> wrote:
Yes wonderful Oliver and Scott I am very interested in the new pump.  Eagerly awaiting more details 
Cheers 🥂 
Well done 
Courtney 
Trippin 
54#101


On Mar 19, 2021, at 9:37 AM, Stefan Schaufert <mail@...> wrote:

Hello Oliver,

how long did these pumps last with you so far? 
How is it possible (for laypeople) to get these pumps (ready for use)?

Best regards
Stefan
A54 #119 Lady Charlyette, currently Exumas
 


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Courtney Gorman
 

Yes wonderful Oliver and Scott I am very interested in the new pump.  Eagerly awaiting more details 
Cheers 🥂 
Well done 
Courtney 
Trippin 
54#101


On Mar 19, 2021, at 9:37 AM, Stefan Schaufert <mail@...> wrote:

Hello Oliver,

how long did these pumps last with you so far? 
How is it possible (for laypeople) to get these pumps (ready for use)?

Best regards
Stefan
A54 #119 Lady Charlyette, currently Exumas
 


Stefan Schaufert
 

Hello Oliver,

how long did these pumps last with you so far? 
How is it possible (for laypeople) to get these pumps (ready for use)?

Best regards
Stefan
A54 #119 Lady Charlyette, currently Exumas
 


Oliver Henrichsen, SV Vela Nautica
 

Hello,

1. My brushless pump motors are a lot more efficient than the very basic brushed flowjet motors. Additional the frigoboat box applies PWM to the old brushed motor to convert 24 volts for a 12 volt pump, that adds even more unefficiency to the old system.

2. Reliability: brushless motors are used in places where reliability and 100% duty is required. Like atomic power plants, industry aso. With my conversion we get rid of most of the wear. At Scott we had to use a simple brushless motor because COVID-19 prevented us from shipping our new designed motors with advanved 100% duty marine bearings. 

3. For the boats using RAWwater for cooling, I created a pump version that flushes the tube system automaticaly to prevent silt. 

4. Scott measured 5 liter per minute at 25% motor speed. As the speed is free to adjust, the flowrate can be adjusted to the optimized rate. I run the pump at 30% and higher in flush mode. 

As we are going to convert an other Boat to the new system we will get more data about the energy savings. 

Kingd regards
Oliver from Vela Nautica 
A54#39 


On Mon, Nov 16, 2020, 23:23 Scott SV Tengah <Scott.nguyen@...> wrote:
Second update: I measured the pump flow rate on the original flojet with a hose and bucket and it was 6.5 liters per minute. 

I measured the flow rate on the brushless set at 25% duty cycle and it was a bit over 5 liters per minute. That lower flow rate probably explains some, but not all of the 60% energy savings I am seeing vs. the brushed motor.

Frigoboat literature states that you need to supply 3.8 liters per minute, so even at my lower flow rate, I'm well over the requirement.

What is really odd is that the fridges seem to run better in that they're running less and use less energy. I surmise there may be some truth in Craig Briggs explanation about how warmer water results in more efficient compressor operation. My freezer, which gets cooling water that has been warmed by the first and second fridges, seems to be drawing less energy. Overall, I have a daily power surplus that is greater than the water pump energy savings (with solar output accounted for) can explain.

So far so good. Now let's see if it lasts!



--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Scott SV Tengah
 
Edited

I asked my technical / warranty contact at Xylem but he couldn't answer because he was working at home. I'll try again as that was 6 months ago. 
 
The software associated with my brush less pump says it's running at 6000rpm but that must be an error. I can still read the text on the spinning motor body and I know my eyes aren't that good! 

On Wed, Nov 18, 2020, 07:10 Mark & Debbie Mueller <brass.ring@...> wrote:
Does anyone know the rpm of the Flojet pump?
--
Mark Mueller
Brass Ring  A54

 

 


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Mark & Debbie Mueller
 

Does anyone know the rpm of the Flojet pump?
--
Mark Mueller
Brass Ring  A54


Porter McRoberts
 

Really cool Scott. 
Thanks for the update. 
Now we all want the schematic and details I’m sure. 

Thanks for figuring this out!  

Porter

Porter McRoberts 
S/V IBIS A54-152
WhatsApp:+1 754 265 2206
Www.fouribis.net

On Nov 16, 2020, at 5:23 PM, Scott SV Tengah <Scott.nguyen@...> wrote:

Second update: I measured the pump flow rate on the original flojet with a hose and bucket and it was 6.5 liters per minute. 

I measured the flow rate on the brushless set at 25% duty cycle and it was a bit over 5 liters per minute. That lower flow rate probably explains some, but not all of the 60% energy savings I am seeing vs. the brushed motor.

Frigoboat literature states that you need to supply 3.8 liters per minute, so even at my lower flow rate, I'm well over the requirement.

What is really odd is that the fridges seem to run better in that they're running less and use less energy. I surmise there may be some truth in Craig Briggs explanation about how warmer water results in more efficient compressor operation. My freezer, which gets cooling water that has been warmed by the first and second fridges, seems to be drawing less energy. Overall, I have a daily power surplus that is greater than the water pump energy savings (with solar output accounted for) can explain.

So far so good. Now let's see if it lasts!



--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Scott SV Tengah
 

Second update: I measured the pump flow rate on the original flojet with a hose and bucket and it was 6.5 liters per minute. 

I measured the flow rate on the brushless set at 25% duty cycle and it was a bit over 5 liters per minute. That lower flow rate probably explains some, but not all of the 60% energy savings I am seeing vs. the brushed motor.

Frigoboat literature states that you need to supply 3.8 liters per minute, so even at my lower flow rate, I'm well over the requirement.

What is really odd is that the fridges seem to run better in that they're running less and use less energy. I surmise there may be some truth in Craig Briggs explanation about how warmer water results in more efficient compressor operation. My freezer, which gets cooling water that has been warmed by the first and second fridges, seems to be drawing less energy. Overall, I have a daily power surplus that is greater than the water pump energy savings (with solar output accounted for) can explain.

So far so good. Now let's see if it lasts!



--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Scott SV Tengah
 

Update: I now have the brush less fridge pump motor up and running. It's self priming by virtue of using the flojet pump head. 

It has a brushless motor which theoretically will last much much longer than the brushed flojet motors. Every single flojet failure I had prior was due to the brushes wearing down and the commutator getting scored beyond repair. 

I surmise the next failure point will be either bearings or the diaphragm in the pump head. I have multiple slightly used backups by virtue of my old failed pumps and also replacing those parts is cheap and possible. 

I've been working with Oliver on this prototype for a while now and it has delivered. A few kinks need to be worked out and today I'll try to measure water output from the old flojet and adjust the speed of the brush less motor to match it. I think frigoboat wants 6l per minute. 

Up shot is that it should last far longer. At my current motor speed it is drawing 60% less power then the flojet brushed motor. Even with two fridges on and the freezer, the freezer evaporator plate, which I think is last to get cooling water is showing -26c so I think current flow rate is sufficient but I'll verify objectively. 

I still have a stock flojet next to it in case this pump dies. That's more about me wanting redundancy because I'm reasonably confident this will far outlast the multiple flojets that I've chewed through. 
 

-- 
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


 

Dean,
They are rated at 30amps at 12 volts, I think they will handle a lot more amps than wll be needed at 24.
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Sun, Jul 12, 2020 at 5:30 PM Dean Gillies <stella@...> wrote:
Bill,
That's a nicely packaged set. I like the fixed leads which makes Porter's task easier.
I am 99.9% certain that they will work just fine as you describe.
The 0.1% risk: I could not find any documented specifications indicating that they are rated for switching 24V. Maybe you've seen that somewhere?
Cheers
Dean

X




Dean Gillies
 

Porter,
I like your thinking re BP analogy.
If we take that further... as we can measure arterial flow with Doppler ultrasound techniques, we could use a simple flow meter installed beside the pump to monitor flow rate on an ongoing basis.

I love how this thread has meandered from hydraulics and electrics through thermodynamics and medicine. All relevant and all interesting!

Cheers,
Dean
SY Stella
A54-154

Sent from my iPhone X


Dean Gillies
 

Bill,
That's a nicely packaged set. I like the fixed leads which makes Porter's task easier.
I am 99.9% certain that they will work just fine as you describe.
The 0.1% risk: I could not find any documented specifications indicating that they are rated for switching 24V. Maybe you've seen that somewhere?
Cheers
Dean

Sent from my iPhone X


Porter McRoberts
 

Thank you Bill. 
That makes it very clear. Time to head to one of my favorite spots: McDonalds Hardware. 
Appreciated!!
Porter 
A54-152. 

Excuse the errors.  
Sent from my IPhone 
Www.fouribis.net

On Jul 12, 2020, at 10:31 AM, CW Bill Rouse <brouse@...> wrote:


Porter, 

According to Frigoboat, the pump selected should move at least 6 liters/min. A 24-volt pump rated at 12 liters/min. running half speed on 12 volts will pump about 6 liters/min.

I am not the electrical expert that Dean Gillis is, but I will try to answer your question. In this schematic, the relay has a 12-volt coil that activates an internal switch. The switch could switch either 12 volts or 24 volts. In the schematic, you will note that only the positive is switched. Dean, feel free to edit or correct.

That relay in the schematic is a very ordinary "Bosch style" normally open 4 pin relay which uses 2 pins (85 & 86) to activate the coil, meaning when 12 volt positive is connected to 85 and 12 volt negative is connected to 86, a switch is closed between 2 pins (30 & 87). There are 2 types of 4 pin relay available; normally open or normally closed. A normally open relay will switch power ON for a circuit when the coil is activated. A normally closed relay will switch power OFF for a circuit when the coil is activated. You want a normally open relay for this project. To further confuse, there are 5 pin relays which allow either normally open or normally closed depending on whether you use 87 (normally open) or the fifth pin 87a (normally closed).


<image.png>

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Thu, Jul 9, 2020 at 4:27 PM Porter McRoberts via groups.io <portermcroberts=yahoo.com@groups.io> wrote:
Bill in your schematic,
The relays are 12VDC control and 24VDC load circuit, easy to put a 2-3 amp fuse on the load circuit.
I've searched for this relay and find it quite difficult to find the definitive solution.  Commonly the reverse is found.
I’d like to build a control board for the pumps.
Might you have a source, or nomenclature that would reveal this hidden gem on the web for me?

A second question:  running a 24v pump at 12v, surely spares the pump, but will it affect the pump volume, as the 1.5+ GPH is quite important, yes?

Always appreciated,

Porter
S/V IBIS A54-152

On Jul 3, 2020, at 3:30 PM, CW Bill Rouse <brouse@...> wrote:

Jamie,

I wish I was on your 54 with you because I have a burning question about all of this. and I have a recommendation for you.

My burning question:
If you see the schematic in my previous post in this thread, you will notice the schematic from a Frigoboat manual. The source of the voltage output from the E51385 blue box to the water pump originates in this schematic with each of the Danfoss Compressor Controllers at the F terminal. In fact, the two wires for each fridge unit come directly from the Danfoss to the E51385. The Frigoboat manual clearly states, regardless of the voltage of the fridge the output on the two F terminals is 12 volts. BTW, the Danfoss operates on 12 or 24 volts, but always outputs 12 volts to Terminal F. Have you checked the output voltage on each of the Danfoss on terminal F and the terminal next to it? I do not see any other way that the E51385 blue box can output 24 volts and if there is 24 volts on the Danfoss fan terminals, I suspect something is wrong with the Danfoss.

My recommendation:
Why don't you do this eliminating the E51385 and eliminate the limitation on amps on the Danfoss terminal F, and run a 24-volt pump??:
<Relays to control water pump.jpg>
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Fri, Jul 3, 2020 at 2:02 PM Jamie Wendell <mysticshadow54@...> wrote:
OK, my "final" update on the Flojet pump and Frigoboat E51385  interface. I cannot explain it, but the interface is definitely out-putting 24 volts to the pump at all times.
Maybe my interface is malfunctioning, so I installed a solid-state relay and a DC converter to step the voltage down to 12 volts. I used a 24-volt relay in place of the E
51385 pump connection and then feed the converter and pump via the live 24-volt terminal box in the engine room. The relay simply engages the pump when the compressors call for it.

A bit more complicated than I would like but the pump runs perfectly now and obviously I no longer get the pump overload signals at the interface. The higher capacity pump may draw more power, but it really cools down the 3 refrigerator units fast.

My next task is to get the brushless motor working to replace the Flojet motor. I will drive it directly via the 24-volt terminal block and eliminate the DC converter.

Until then I am "over and out" regarding this perplexing issue with the E
51385. I really appreciate all the suggestions and assistance, but will report once I have the brushless motor controller operational. That will be the gold standard.

Jamie
Phantom, A54 #44




 

Porter, 

According to Frigoboat, the pump selected should move at least 6 liters/min. A 24-volt pump rated at 12 liters/min. running half speed on 12 volts will pump about 6 liters/min.

I am not the electrical expert that Dean Gillis is, but I will try to answer your question. In this schematic, the relay has a 12-volt coil that activates an internal switch. The switch could switch either 12 volts or 24 volts. In the schematic, you will note that only the positive is switched. Dean, feel free to edit or correct.

That relay in the schematic is a very ordinary "Bosch style" normally open 4 pin relay which uses 2 pins (85 & 86) to activate the coil, meaning when 12 volt positive is connected to 85 and 12 volt negative is connected to 86, a switch is closed between 2 pins (30 & 87). There are 2 types of 4 pin relay available; normally open or normally closed. A normally open relay will switch power ON for a circuit when the coil is activated. A normally closed relay will switch power OFF for a circuit when the coil is activated. You want a normally open relay for this project. To further confuse, there are 5 pin relays which allow either normally open or normally closed depending on whether you use 87 (normally open) or the fifth pin 87a (normally closed).


image.png
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Thu, Jul 9, 2020 at 4:27 PM Porter McRoberts via groups.io <portermcroberts=yahoo.com@groups.io> wrote:
Bill in your schematic,
The relays are 12VDC control and 24VDC load circuit, easy to put a 2-3 amp fuse on the load circuit.
I've searched for this relay and find it quite difficult to find the definitive solution.  Commonly the reverse is found.
I’d like to build a control board for the pumps.
Might you have a source, or nomenclature that would reveal this hidden gem on the web for me?

A second question:  running a 24v pump at 12v, surely spares the pump, but will it affect the pump volume, as the 1.5+ GPH is quite important, yes?

Always appreciated,

Porter
S/V IBIS A54-152

On Jul 3, 2020, at 3:30 PM, CW Bill Rouse <brouse@...> wrote:

Jamie,

I wish I was on your 54 with you because I have a burning question about all of this. and I have a recommendation for you.

My burning question:
If you see the schematic in my previous post in this thread, you will notice the schematic from a Frigoboat manual. The source of the voltage output from the E51385 blue box to the water pump originates in this schematic with each of the Danfoss Compressor Controllers at the F terminal. In fact, the two wires for each fridge unit come directly from the Danfoss to the E51385. The Frigoboat manual clearly states, regardless of the voltage of the fridge the output on the two F terminals is 12 volts. BTW, the Danfoss operates on 12 or 24 volts, but always outputs 12 volts to Terminal F. Have you checked the output voltage on each of the Danfoss on terminal F and the terminal next to it? I do not see any other way that the E51385 blue box can output 24 volts and if there is 24 volts on the Danfoss fan terminals, I suspect something is wrong with the Danfoss.

My recommendation:
Why don't you do this eliminating the E51385 and eliminate the limitation on amps on the Danfoss terminal F, and run a 24-volt pump??:
<Relays to control water pump.jpg>
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Fri, Jul 3, 2020 at 2:02 PM Jamie Wendell <mysticshadow54@...> wrote:
OK, my "final" update on the Flojet pump and Frigoboat E51385  interface. I cannot explain it, but the interface is definitely out-putting 24 volts to the pump at all times.
Maybe my interface is malfunctioning, so I installed a solid-state relay and a DC converter to step the voltage down to 12 volts. I used a 24-volt relay in place of the E
51385 pump connection and then feed the converter and pump via the live 24-volt terminal box in the engine room. The relay simply engages the pump when the compressors call for it.

A bit more complicated than I would like but the pump runs perfectly now and obviously I no longer get the pump overload signals at the interface. The higher capacity pump may draw more power, but it really cools down the 3 refrigerator units fast.

My next task is to get the brushless motor working to replace the Flojet motor. I will drive it directly via the 24-volt terminal block and eliminate the DC converter.

Until then I am "over and out" regarding this perplexing issue with the E
51385. I really appreciate all the suggestions and assistance, but will report once I have the brushless motor controller operational. That will be the gold standard.

Jamie
Phantom, A54 #44




Craig Briggs
 
Edited

Hi Scott,
Yes, it does seem a bit counter-intuitive that warmish water is more efficient than cold water. Here is a paraphrase from my system's technical manual that may help in understanding it.

The reason (that 90F sea water is optimum) is that in the refrigeration cycle, after the high pressure liquid refrigerant has passed through the expansion valve and gotten cold by converting to a gas, then passed through the cooling coil and taken on the heat of the refrigerated area and then gone back through the compressor, it is about 140F and only needs to be cooled to about 120F to condense back to liquid and repeat the cycle. Thus 80-90F cooling water is all that's needed. In colder water the liquid refrigerant is too cold and is stored in the condenser and the system operates with a much lower suction pressure as the pressure difference across the expansion valve is reduced. This will substantially decrease the capacity of the system and increase the running
time.

That same manual offers corrective solutions for operating in cold open ocean water by using a gate valve or a water by-pass to restrict the flow of too cold water and get the drier and receiver temperature up to about 95F.

From just an everyday non-technical vantage point, consider that the marine market is absolutely insignificant to the global refrigeration market (no special refrigerants, etc. - there is no such thing as "marine refrigeration" outside of the marketing department). Nobody has cold water cooling - Eskimos don't need it! Household refrigerator cooling coils have ambient temps in the 70's or 80's or more (room temp). Apartments and buildings have water source cooling tower ambient temps in the 80's and 90's (or 100's here in Florida) and, therefore, cooling water temps are the same. Those systems are, in fact, at maximum efficiency because they are providing cooling at the condensing temperature of the refrigerant - 80 to 90 ish, depending on the refrigerant.

And, oh by the way, I just Googled Windy.com, clicked on the water temperature, and from 20 S to 20 N, including the entire Caribbean, the water is in the 80's. At my dock in Florida it's 92F. My A/C and refrigerator love it! As do all those cruisers who used to be there before Covid.

I would assert that no marine refrigeration system is designed to operate in extra-tropical ocean cold water temperatures - unless it has a gate valve or by-pass for cold water use. That pump life has been seen to be inversely correlated to ambient temperature is perfectly understandable. It's not the cold cooling water, it's the cool ambient temperature. The cold cooling water is actually increasing the running time and fighting against the cool ambient temperature that is decreasing the running time. 

It would be fun to experiment with a system with a gate valve or by-pass valve in a cold place. Run the system with 55 degree water for a few days and log the run times.  Then throttle down the valve to get 95 degree water for a few days and log that. Then check Oliver's fancy logging system and see what it shows. Dollars to donuts the warm water will see less pump usage.

Fun topic for a locked down Covid evening, thanks for initiating the discussion,
Cheers, Craig


Scott SV Tengah
 

HI Craig,

I'm a little surprised that you're stating that our water cooled Danfoss refrigeration systems perform optimally with water temps above that which we experience in the tropics. That begs the question -  why didn't they design it for maximum efficiency given a water temperature that you would actually experience in the ocean?

My primary concern is pump life, which is directly related to pump duty cycle. Oliver logs his pump duty cycle (fancy computerized system) and noted that it went from 15% in colder waters to about 75% duty cycle when he got to the Caribbean. 

I surmise the hot ambient air temps around the cooling box contribute to that, but for the purposes of comparing pump life for those in warm climates vs. pump life for those in cool climates, pump life seems to be inversely correlated with temperature. Those reporting super long pump lives seem to be in colder areas.

While I don't have Oliver's fancy logging system, I can attest that our refrigeration system uses considerably more power per day and our pumps lasted for much less time when comparing our experiences in the Caribbean vs. the Med. That implies to me that, when all is considered, colder temps mean the system is running less often.

--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Craig Briggs
 

While cold seawater is, indeed, much better at cooling than warm water, it is less efficient for our refrigeration systems. Having the cooling water be at about the condensing temperature of the refrigerant is ideal. Typically, systems are most efficient with 90 degrees F / 32 C sea water (varies with the refrigerant). At much lower temperatures, like 55F/13C up north, the system will operate with a lower suction pressure and the pressure across the expansion valve is reduced which decreases system capacity and increases running times. We've got a gate valve on the sea water outlet that can be partially closed in very cold water to restrict flow and increase temperature. Put your hand on the drier or receiver and it should be about body temp. Recirculating the fresh water in your tank instead of using sea water is great and has the added benefit of keeping the beer cold when you're on the hard. 
Cheers, Craig