Adding 507a to 404a-any problems?

[TJ D]

Thanks, Pete. The tech here is more like a guy with a van and a couple of gauges. He also fixes diesels, and probably does engine work on old VW's too. Jack of all trades sort of guy, and not really someone I'd be too keen to do something of any consequence.



However, we will be in Gibraltar soon, and there's a good outfit there. I'll call ahead and discuss, and maybe we can get this thing finally sorted.



Gracias, amigos.

[OzePete]

Originally Posted by TJ D

Thanks, Pete. The tech here is more like a guy with a van and a couple of gauges. He also fixes diesels, and probably does engine work on old VW's too. Jack of all trades sort of guy, and not really someone I'd be too keen to do something of any consequence.



However, we will be in Gibraltar soon, and there's a good outfit there. I'll call ahead and discuss, and maybe we can get this thing finally sorted.



Gracias, amigos.

That would be best. When you contact Gibraltar suggest they have a 2.75 Mt length of 0.70 ID capillary a Sporlan or similar 030 or 050 flared filter dryer and some R404a refrigerant ready for you.

In the meantime you might want to raise the CP valve temperature a little to ease the start up issue slightly.

TJ. I had to edit the capillary length / ID suggested as my original comps were wrongly for R134a. The highlighted now are correct for R404a.

Cheers OzePete

[OzePete]

Hi TJ,
Please check my previous post there is an important edit...

Cheers OzePete

[TJ D]

Hi Pete, well received. I put the pressure back up to the vendor's spec of 15psi. It was then off for an hour or so, and then started on the first try.


The gauges have left the boat, so I'll be with this until we get to Gib and a more professional shop.


Thanks again.

[Richard Kollmann]

TJ, Because there is only two line connections on that Automatic expansion valve it is internally equalized with a design leak in valve seat. With excessive amount of liquid pressure from 404a the thermostat controlling compressor will need an extended time differential.
I am concerned that repeated start attempts can cause another module to fail. It may be a long time before a final fix to the system can be done. I recommend readjusting AEV valve which is the only thing controlling the refrigerant flow volume in your unit to around 20 psi producing near zero degrees F plate temperatures. I understand there are no gauges now connected to system. The valve can be set manually, turned clock wise to increase plate temperature/ decreasing pressure. Increasing spring pressure on diaphragm reducing deferential pressure on compressor starts. If you do decide to adjust pressure there are marks on the adjusting shaft, But I would count and record turns of adjusting knob. daily until plate temp is around zero degrees F.

I recommend you wait to talk with Cleave as no one else can give good advice on his designs. With dual plates and a built in refrigerant receiver you would not want a capillary tube flow control device. If you do not look for a simple less destructive fix you will dig yourself in deeper trouble month after month. Seafrost has a reputation of always making things right.

[TJ D]

Originally Posted by Richard Kollmann

TJ, Because there is only two line connections on that Automatic expansion valve it is internally equalized with a design leak in valve seat. With excessive amount of liquid pressure from 404a the thermostat controlling compressor will need an extended time differential.
I am concerned that repeated start attempts can cause another module to fail. It may be a long time before a final fix to the system can be done. I recommend readjusting AEV valve which is the only thing controlling the refrigerant flow volume in your unit to around 20 psi producing near zero degrees F plate temperatures. I understand there are no gauges now connected to system. The valve can be set manually, turned clock wise to increase plate temperature/ decreasing pressure. Increasing spring pressure on diaphragm reducing deferential pressure on compressor starts. If you do decide to adjust pressure there are marks on the adjusting shaft, But I would count and record turns of adjusting knob. daily until plate temp is around zero degrees F.

I recommend you wait to talk with Cleave as no one else can give good advice on his designs. With dual plates and a built in refrigerant receiver you would not want a capillary tube flow control device. If you do not look for a simple less destructive fix you will dig yourself in deeper trouble month after month. Seafrost has a reputation of always making things right.

Richard, we're pretty happy with Seafrost. I didn't really like the part where the 134 freezer was barely below 32, and he said that was just fine, but otherwise-solid service from those guys.



Unfortunately, he's on vacation for a couple of weeks, so I had to take matters into my own hands. Hopefully, he'll be back by the time we're ready to dig into it again.



I cranked it up to 15psi, and set a pretty big temp differential between stop and start, and that's helping. The last couple of starts have been without failure. We've got more temp variation in the box than I'd really like, but it seems like we're doing the best we can with the configuration as it is now.



I do appreciate all the help-thanks much.

[Richard Kollmann]

One of my module test stand is an Adler Barbour unit with 134a Danfoss BD50. During a test two days Box temperature reached -16 degrees F. Normal icebox conversion refrigeration freezer temperatures should be less than +10 degrees F for daily ice cube production +4 to +8 degrees F.

You should be able to solve the start problem and operate freezer at zero to plus 10 degrees by increasing valves adjustable spring pressure. By counting turns it can always be returned to present setting.

[a64pilot]

This is box temps of a 14 cu Ft spill over split approx 50/50.
A dual cold plate R-134a with a BD80 compressor, and is about as cold as I can get it, in December in Brunswick Ga, compressor running pretty much all of the time.
-5 F or so is about all I can get in Summer in 90F water.
R-134a can get pretty cold.
Of course when you get into negative numbers the coefficient of efficiency suffers, which means it cost power to get cold.

[Djarraluda]

Originally Posted by LeaseOnLife

here you find the ingredients for each: R404a has a a tiny bit R134A, R507 does not. Will that make a difference, likely not:


R404A / R507 - Friedrichs Kältemittel - Friedrichs Kältemittel


Would the cost to evacuate, recycle and fill with R507 be too much? Then you know what you have, and not some unknown mixture.

I realise the discussion has moved-on a tad, but to close the gas mixtures issue, perhaps, ....
The absolute most critical element of this is to check the oil compatibility, can not mix synthetic and mineral.
Once we know the options both use the same oil, we look at the actual composition and see that 404a and 507 are both blends. Being blends, they are used in systems to benefit from the "glide". This is the fact that they will change state at different temp/pressure points, so as the heat exchange takes place, the temp on the other surface is optimised.
The fact they change state at different temps means that the actual component that gets lost is typically one of the gases in the blend, not equally across all of them. So the top-up should be richer in one than another if we want to maintain the same performance.
It is not too critical, we can loose 1/4 of the mix a couple of times and still maintain some 90% or more of the performance, but the loss of performance means you will use a higher power. May not be critical, but at least you should be aware. Full regas is best.
Roger

[Richard Kollmann]

Originally Posted by Djarraluda

I realise the discussion has moved-on a tad, but to close the gas mixtures issue, perhaps, ....
The absolute most critical element of this is to check the oil compatibility, can not mix synthetic and mineral.
Once we know the options both use the same oil, we look at the actual composition and see that 404a and 507 are both blends. Being blends, they are used in systems to benefit from the "glide". This is the fact that they will change state at different temp/pressure points, so as the heat exchange takes place, the temp on the other surface is optimised.
The fact they change state at different temps means that the actual component that gets lost is typically one of the gases in the blend, not equally across all of them. So the top-up should be richer in one than another if we want to maintain the same performance.
It is not too critical, we can loose 1/4 of the mix a couple of times and still maintain some 90% or more of the performance, but the loss of performance means you will use a higher power. May not be critical, but at least you should be aware. Full regas is best.
Roger

Before the subject of freezer low temperature refrigerants R502, 407a and 404a gets side tracked, it would be of interest to know the advantage or disadvantages of sub zero temperatures boxes for pleasure boats.
If a zero degree F box temperature using 134a refrigerant can protect frozen food for a month is it wise to convert to the less friendly blended refrigerants?
Are there approvals from small Direct Current compressor manufactures to use high pressure refrigerants?
Is there anyone else with a system containing one of the high pressure blended refrigerants?

[OzePete]

Originally Posted by Richard Kollmann

Before the subject of freezer low temperature refrigerants R502, 407a and 404a gets side tracked, it would be of interest to know the advantage or disadvantages of sub zero temperatures boxes for pleasure boats.
If a zero degree F box temperature using 134a refrigerant can protect frozen food for a month is it wise to convert to the less friendly blended refrigerants?
Are there approvals from small Direct Current compressor manufactures to use high pressure refrigerants?
Is there anyone else with a system containing one of the high pressure blended refrigerants?

The greatest curse of the refrigeration industry in recent times has been the proliferation of different refrigerant gases and it's worse for the consumer because they are paying for the consequences of this madness! Just two (occasionally a third) refrigerants did the job for decades previously, and more efficiently in all areas! This mess we have now is mostly about money IMO!

I agree, R134a is more than adequate for most marine fridge / freezer applications being able to achieve minus -25C if engineered correctly.

Changing a system from it's original refrigerant to another is not advisable. If a system is correctly engineered for a particular refrigerant it may work on others but performance and longevity are usually compromised. Besides while R134a is commonly available even in remote parts that cruisers get to, chances of obtaining some of the new creations is very doubtful!

To answer Richards question, we engineer our systems to operate with R134a only and don't support any change to other gases.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[a64pilot]

You can find all kinds of things on the Internet, but the USDA recommends 0F for long term frozen food storage, and 40F or lower for the fridge.
https://www.fsis.usda.gov/wps/wcm/co...afety/ct_index
No need to go lower for safety, however ice cream due to its fat content I believe is harder if taken down to -5 F.

So as silly as this may sound but if you can keep ice cream, your in, no need for anything colder.
Ice cream is the acid test.

[Richard Kollmann]

Originally Posted by OzePete

The greatest curse of the refrigeration industry in recent times has been the proliferation of different refrigerant gases and it's worse for the consumer because they are paying for the consequences of this madness! Just two (occasionally a third) refrigerants did the job for decades previously, and more efficiently in all areas! This mess we have now is mostly about money IMO!

I agree, R134a is more than adequate for most marine fridge / freezer applications being able to achieve minus -25C if engineered correctly.

Changing a system from it's original refrigerant to another is not advisable. If a system is correctly engineered for a particular refrigerant it may work on others but performance and longevity are usually compromised. Besides while R134a is commonly available even in remote parts that cruisers get to, chances of obtaining some of the new creations is very doubtful!

To answer Richards question, we engineer our systems to operate with R134a only and don't support any change to other gases.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

We have been aware for 12 years that mobile refrigeration containing 134a refrigerant was already in the planning phase to be replaced. The reason for stopping the use of 134a is its Global Warming Potential (GWP) of 1430. When CFC Freon 12 was replaced twenty years ago with HFC 134a it was not a drop in refrigerant either. The marine refrigeration industry will again not find a drop in HFO refrigerant compatible with mineral oil or even 134a now Ester lubricating oil.

The only new GWP replacement refrigerant that comes close is HFO-1234yf Its performance in automobile air conditioners is about the same as 134a. The Global Warming Potential for HFO 1234yf is only 4 as compared to 1430 for 134a. Some autos started using HFO-1234yf in 2013 even though it is reported as slightly flammable. HFO refrigerant require PAG oil to be considered as a drop in replacement if system already has PAG oil. All small 134a refrigeration systems presently have POE Ester oil and not PAG oil

It is also believed another change requirement for HFO-1234yf is special servicing fittings and unique servicing equipment. It is also reported that HFO-1234yf will not be available in small containers.

To add to the new refrigerant confusion there are at least three different chemical mixes for HFO-1234yf , yfE and yfZ plus a number of other refrigerants under development.

Likely the pleasure boat refrigeration owner will lose out again. If planing to replace old refrigeration I would hold off to see if 134a units can ever be converted to the new required standards.

[a64pilot]

Or when the demise of R134a is announced buy a few cans and put them away, they will last a very long time.
I still have some R12 in cans I bought last Century.

[Richard Kollmann]

Originally Posted by a64pilot

Or when the demise of R134a is announced buy a few cans and put them away, they will last a very long time.
I still have some R12 in cans I bought last Century.

A64pilot, I like you bought a supply of R12 before prices skyrocketed. I read every copy of the Federal Register dealing with developing EPA regulations based on the Clean Air
Act. When the EPA asks for comments only the special interests offered advice helpful to their objectives. Because no one in the marine industry seem to offer objection to many of the unjustified requirements like; All refrigerants are regulated the same, Components for refrigeration can not be shipped with refrigerant in them. Fortunately with the Federal EPA every one is aloud to request a meeting to abate unrealistic requirements after a citation is issued. The Federal EPA without any formal announcement has ignored some of their own regulations like allowing anyone to purchase and use HFC 134a refrigerant without a license. The question now is what other parts of the refrigerant EPA regulations are they ignoring. Local EPA regulations can not be weaker than federal regulations but they can be stronger and more restrictive.

The marine pleasure boat industry has been in trouble since the late 1970s. More of these companies have gone out of business because of their marketing plans or they have been acquired and combined with other small companies by an investment parent company. Other refrigeration companies to stay in business had to diversify their product line, like Frigoboat Italy, Figoboat US, Electric Iceman and Technautics.