Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 27-11-2019, 16:43   #1
Registered User

Join Date: Jan 2013
Location: Antigua
Boat: Custom 55
Posts: 907
Freezer compressor speeding up late in cycle

Hi reefer gurus,



I think I am low on charge on my 404a system, but would like to bounce this off you guys before I add gas.



At a plate temp of about minus 2f, the compressor noticeably speeds up, and amperage drops. It will just run and run, and achieve about minus 5, no more than that.



It is a bit hard to tell with my plates exactly where the line is where the refrigerant is boiling off, but there is definitely no frost on the line exiting the plate.



My thought is to add a small shot of gas and observe, but I just want to check in and see if I might be missing something.



Thanks, mates. We are leaving to cross the Atlantic in a few days, so I would like to get this sorted prior to that.
__________________

__________________
TJ, Jenny, and Baxter
svrocketscience.com
TJ D is offline   Reply With Quote
Old 28-11-2019, 08:17   #2
Registered User

Join Date: Jun 2019
Posts: 115
Re: Freezer compressor speeding up late in cycle

Can you post pictures, model#'s?

I have some ideas, but you need to tell us what we are working on.
Im guessing its a Grunert/Marine air?
__________________

Coolerking is offline   Reply With Quote
Old 28-11-2019, 09:50   #3
Marine Service Provider

Join Date: Aug 2004
Location: Ft. Lauderdale
Posts: 1,422
Re: Freezer compressor speeding up late in cycle

Quote:
Originally Posted by TJ D View Post
Hi reefer gurus,



I think I am low on charge on my 404a system, but would like to bounce this off you guys before I add gas.



At a plate temp of about minus 2f, the compressor noticeably speeds up, and amperage drops. It will just run and run, and achieve about minus 5, no more than that.



It is a bit hard to tell with my plates exactly where the line is where the refrigerant is boiling off, but there is definitely no frost on the line exiting the plate.



My thought is to add a small shot of gas and observe, but I just want to check in and see if I might be missing something.



Thanks, mates. We are leaving to cross the Atlantic in a few days, so I would like to get this sorted prior to that.
Your request for help on an unknown designed refrigeration system with almost no technical information guidance is puzzling. Compressor speeds up at -2 degree F and amperage draw drops. This must mean compressor is a large DC compressor or engine driven. Amperage change from unit running in the past is an excellent indicator when measuring current
Performance. Increase in amp draw would indicate poor condenser cooling while decrease in system amperage points to loss of refrigerant.

Refrigerant boiling as you say in evaporator is normally referred to as Degrees of superheat from beginning of evaporator coil to the end of its flow leaving evaporator. Frost on line leaving evaporator on your unit at -5 degrees may be or not have any troubleshooting value because of the blended 404a refrigerants drift inside eevaporator.

Assuming it turns out there has been a loss of refrigerant the correct procedure is not to add refrigerant as present remaining refrigerant 404a blend is defined as fractured. Fractionation is the change in composition of a blend because one or more of the components is lost. When compressor stops refrigerant blends in 404a separate in your system and the one with the highest vapor pressure will find a leak point reducing the blendís heat absorbing performance.

If you do confirm that there is a loss of refrigerant and the leak is small you may be better off completing the planed crossing.
Richard Kollmann is offline   Reply With Quote
Old 28-11-2019, 11:01   #4
Registered User

Join Date: Jan 2013
Location: Antigua
Boat: Custom 55
Posts: 907
Re: Freezer compressor speeding up late in cycle

Hello all, this is a seafrost bdxpx system.


I replaced a 134a bdxp with this unit, and while we were mucking around with getting the pressure right, we had a few connection/disconnections at the service port, including a measurement between high/low pressure. A bit of gas was lost during this conversion, and we haven't seen any change in operational characteristics since. I do not believe we have a leak presently.



I'm pretty convinced we have a loss of charge at this point. I can't get 404a here, however. They have some gases that are 'compatible' with 404a, but i don't know if I should be evacuating the system and going entirely with the euro gas, or if it's ok just to add.



The charge is 7oz. I believe that this is 280 grams if we do a full charge based on the info I could find.



Sorry-no pictures. Slow wifi here.



Anyway, do you guys think I will be ok adding a compatible, but not pure 404 gas, or is it better to evacuate? Am I asking for trouble if I add anything other than straight 404a??


Cleave seems to be off for the long weekend, unfortunately.



BTW, the gas I sourced here is called 'freeze 22', it lists itself as a direct replacement for r-22, 404, and a few others.



Thanks, TJ
__________________
TJ, Jenny, and Baxter
svrocketscience.com
TJ D is offline   Reply With Quote
Old 28-11-2019, 11:55   #5
Marine Service Provider

Join Date: Aug 2004
Location: Ft. Lauderdale
Posts: 1,422
Re: Freezer compressor speeding up late in cycle

Quote:
Originally Posted by TJ D View Post
Hello all, this is a seafrost bdxpx system.


I replaced a 134a bdxp with this unit, and while we were mucking around with getting the pressure right, we had a few connection/disconnections at the service port, including a measurement between high/low pressure. A bit of gas was lost during this conversion, and we haven't seen any change in operational characteristics since. I do not believe we have a leak presently.



I'm pretty convinced we have a loss of charge at this point. I can't get 404a here, however. They have some gases that are 'compatible' with 404a, but i don't know if I should be evacuating the system and going entirely with the euro gas, or if it's ok just to add.



The charge is 7oz. I believe that this is 280 grams if we do a full charge based on the info I could find.



Sorry-no pictures. Slow wifi here.



Anyway, do you guys think I will be ok adding a compatible, but not pure 404 gas, or is it better to evacuate? Am I asking for trouble if I add anything other than straight 404a??


Cleave seems to be off for the long weekend, unfortunately.



BTW, the gas I sourced here is called 'freeze 22', it lists itself as a direct replacement for r-22, 404, and a few others.



Thanks, TJ
Seafrost's BDXP 12/24 volt system is unique to any other boat refrigeration system in that evaporator temperature and refrigerant Superheat flow is regulated by a pressure regulating, manually set, valve. Cleave is the only one I know who can assist you in any changes to your system. I assumed he approved the change to 404a. I know of no refrigerants compatible to add to 404a. Freon 502 was the prefered refrigerant in the past for the now 404a. Seven ounces of low pressure 134a would not perform the same as 7 ounces of high pressure lower temperature 404a.

What you first reported seams to be a equilibrium temperature between compressor output and refrigerant phase temperature flow resulting in compressor never shutting off. And the Danfoss AEO module sensed the equilibrium and would increase speed to the most inefficient max speed if thermostat is not satisfied.. If there is no concern over refrigerant loss I suggest you reset the thermostat to a point higher maintaining box freezer temperature between 10 and 15 degree F for your crossing. Any temperature below 22 degrees F will preserve food quality for at least a month.
Richard Kollmann is offline   Reply With Quote
Old 28-11-2019, 12:36   #6
Registered User

Join Date: Jan 2013
Location: Antigua
Boat: Custom 55
Posts: 907
Re: Freezer compressor speeding up late in cycle

Thanks, Richard.


Hopefully I can reach Cleave before we go. The 404 conversion was a whole new unit. We had a 134a unit that failed, and I elected to drop in the 404 in its place. This was done in consultation with SeaFrost, of course.



It works well enough now, but my main issue is power use. I really like to 'turbo cool' the freezer when we're running the engine or have an excess of solar watts going, to reduce the effective power consumption at other times. It's nice to crank the box way down when motoring and not see it turn on for a day afterwards. I can't do that now.


We still have a few days, so hopefully we can connect with Cleave before we go. I would prefer to have it working as designed before this long trip, of course. Worst case, we'll do as you suggest and just deal with a warmer box. I could stand to lose a few pounds, so if we can't have ice cream, that's ok...
__________________
TJ, Jenny, and Baxter
svrocketscience.com
TJ D is offline   Reply With Quote
Old 28-11-2019, 14:47   #7
Registered User

Join Date: Jun 2019
Posts: 115
Re: Freezer compressor speeding up late in cycle

I could be wrong, but if I remember correctly, that system that Cleve designed used a unique "normally open" solenoid panel with relays sealed in a box…?
Coolerking is offline   Reply With Quote
Old 28-11-2019, 14:54   #8
Registered User

Join Date: Jan 2013
Location: Antigua
Boat: Custom 55
Posts: 907
Re: Freezer compressor speeding up late in cycle

I'm not sure about that, honestly. I haven't really needed to do anything to the system other than replace a control module.
__________________
TJ, Jenny, and Baxter
svrocketscience.com
TJ D is offline   Reply With Quote
Old 29-11-2019, 10:29   #9
Musician & 50T Master
 
Symphony's Avatar

Cruisers Forum Supporter

Join Date: Jul 2011
Location: Ct
Boat: Vicem 58 (ex-Tartan 41)
Posts: 618
Re: Freezer compressor speeding up late in cycle

subscribed!
(subscribe button gone 404)
__________________
Symphony
Live slow, sail fast, motor super fast
Symphony is offline   Reply With Quote
Old 29-11-2019, 11:18   #10
Registered User

Join Date: Jan 2013
Location: Antigua
Boat: Custom 55
Posts: 907
Re: Freezer compressor speeding up late in cycle

Well...

I finally found a can tap today (for 40 euros-gah).


I also got a tech down here who really wasn't much help. I explained what I had done, putting a 404 unit into a system that had previously been 134. He rolled his eyes a bunch, said that there was no way this could possibly work, he had never heard of anything so dumb in 23 years in the business.



I told him that I did it with the blessing of the manufacturer, but this mattered little.


Anyway, he added some gas, and the system is now getting much colder. Where I was lucky to see -2f at the plates previously, I've now it -7 and it's still going down.



HOWEVER... I think he put in too much gas. The compressor wouldn't start, threw the 3 flash warning. I have a 25 degree spread between off and on to give the high/low side a chance to equalize (I've encountered this failure to start before). But, it just woudn't go on, indicating overcharge, I reckon.



So, I broke out my trusty gauge set, and equalized the high and low sides manually, and things fired right up. Of course, this can't be standard procedure. Even after this operation, the low side showed 60 psi at startup.



Currently, I'm running 15psi on the low side, and the high side is at 280. This is at a -7 plate temp.



I've set the shutoff point at -15 for this test run, and will put in a 40 degree rise prior to startup. I've found with the 404, there needs to be a big temp rise between off/on regardless. The higher pressures seem to be tricky with the danfoss units.



I think Cleave is on vacation. Just VM, no call back. That's unfortunate timing for me.
__________________
TJ, Jenny, and Baxter
svrocketscience.com
TJ D is offline   Reply With Quote
Old 29-11-2019, 12:24   #11
Marine Service Provider

Join Date: Aug 2004
Location: Ft. Lauderdale
Posts: 1,422
Re: Freezer compressor speeding up late in cycle

You reported, (I also got a tech down here who really wasn't much help. I explained what I had done, putting a 404 unit into a system that had previously been 134. He rolled his eyes a bunch, said that there was no way this could possibly work, he had never heard of anything so dumb in 23 years in the business. )

This tech was very smart not dumb. Tech knows unit will work for some time at 15 pounds low pressure and 280 high pressure, the question is for how long before it self destructs. Fifteen psi suction could produce minus 22 degrees in evaporator but heat from 280 psi in compressor that is not thermally protected like other hermetically sealed compressors is a mistake. Cleave at Seafrost is the only advice you should pay attention to.
Richard Kollmann is offline   Reply With Quote
Old 29-11-2019, 12:38   #12
Registered User

Join Date: Jan 2013
Location: Antigua
Boat: Custom 55
Posts: 907
Re: Freezer compressor speeding up late in cycle

But... Richard-


This setting is from Cleave. the 15 psi suction. I have no control over the high pressure side. I followed his instructions. This installation was done entirely at the direction of Cleave.



Where are you coming from??


And, alas, Cleave ain't answering his phone now.
__________________
TJ, Jenny, and Baxter
svrocketscience.com
TJ D is offline   Reply With Quote
Old 29-11-2019, 13:13   #13
Marine Service Provider

Join Date: Aug 2004
Location: Ft. Lauderdale
Posts: 1,422
Re: Freezer compressor speeding up late in cycle

If this is a BD80 compressor Danfoss rates it as a Low Back Pressure only unit. If you are following Cleave's instructions he knows what works and what does not, I will shut up. Fifteen PSI low pressure is not the problem it is the 280 psi high pressure that concerns me.
Richard Kollmann is offline   Reply With Quote
Old 29-11-2019, 13:55   #14
Registered User

Join Date: Jan 2016
Location: Ventura, California, USA
Boat: Catalina 30
Posts: 591
Re: Freezer compressor speeding up late in cycle

Non-condensables in the circuit? Or did failure to evacuate a fractionated charge lead to overcharge with the top-off?
Brewgyver is offline   Reply With Quote
Old 29-11-2019, 15:02   #15
Registered User

Join Date: Jan 2013
Location: Antigua
Boat: Custom 55
Posts: 907
Re: Freezer compressor speeding up late in cycle

We don't have the ability to evacuate here-no time and nobody who can do it, so we did the best we could with what was at hand.


Fractionation? I don't know. There's no evidence of a leak-the unit's operating characteristics haven't changed in months of operation. We seem to have lost charge last summer when messing with it. The unit only holds 7 oz, so a few connects/disconnects of the service ports probably did it.



Anyway, with the top-off, I took the plates to -15f, which was about 12 degrees colder than we could achieve before it.



I'm just now letting it warm up and waiting to see what happens when we reach the 'turn on' temp again. I've got the gauges connected still, and pressures are sitting at a bit under 60 psi with the unit having been off for about 90 minutes. I don't know if this is too high for 404a or not. We shall see if the compressor starts or stalls soon. I'm guessing I'll be seeing 3 flashes...
__________________

__________________
TJ, Jenny, and Baxter
svrocketscience.com
TJ D is offline   Reply With Quote
Reply

Tags
compressor, freezer

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
For Sale: Indel Isotherm Freezer Box - Compressor / Strainer 1.87cf Air Cooled $700 Conchfritterz Classifieds Archive 3 13-01-2012 22:02
Air-Cooled Compressor vs Air/Water-Cooled Compressor melidramatic Plumbing Systems and Fixtures 4 06-02-2011 08:35
For Sale: Portable Fridge/ Freezer, Danfoss Compressor Boatguy30 Classifieds Archive 3 13-12-2010 18:31
Advice on Replacing Reefer / Freezer Compressor? janders Plumbing Systems and Fixtures 8 20-12-2009 15:35

Advertise Here


All times are GMT -7. The time now is 18:57.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.