Frigoboat keel cooled refer runs hot

[pcmm]

I'm in the middle of an extensive refit and just got back in the water, initially the refer wasn't working at all. The compressor would run, the evaporator plate wouldn't get cold. I discovered that one of the connections was missing an O ring and was leaking badly. I replaced the o ring and refilled the system using an automotive r134a refill kit. That seems to have worked, the Evaporator plate is now frosting over and the inbox is getting cold. The problem is the compressor is running hotter than I think it should and th system is drawing more amps than it should. (I don't know exactly lay as I don't have an ammeter hI owed up but the db50 drained my house bank down to 11.92v in 2 days and it's a 400ah bank!

Any suggestions? Do I need to evacuate the system and recharge?

[a64pilot]

I would pull a vacuum, and do you know correct charge by weight?


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[pcmm]

Originally Posted by a64pilot

I would pull a vacuum, and do you know correct charge by weight?


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That's art of the problem. I can't find much on the frigobost systems for the charge information and I don't have the equipement to pull a vacuum. I would need gauges and avacuum pump for that. Question is, is that equipement more expensive than having a tech in to fix it? I have no problems tackling it if I can get the gear at a reasonable cost.

[a64pilot]

If moisture got in, then it combined with the oil will form acid, and that obviously will cause problems, so you vacuum to get the moisture out, low pressure will cause water to boil at room temp and that will remove moisture. Takes a deep vacuum and won't happen in a few minutes though.
If I were you, I'd hire a tech if you can find a good one.


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[SV THIRD DAY]

The gear (a gauge set and vacuum pump) will definitely cost you less than a refrigeration tech visit if you buy something cheap from say Harbor Freight. Refrigeration techs charge like Cardiac Surgeon these days. However, without the info and skills to go along with that gear...are you just spinning your wheels? It depends on your comfort level and willingness to learn. The problem I see is that very few Refrigeration Tech actually know what they are doing and will use your project to learn as they go. Given that, I would rather YOU be the one learning and then have the gear to self-service your own equipment. If could just be a simple vacuuming down and recharging is all you need which isn't rocket science.

[JimsCAL]

I have that system on my 1985 Cal 33. Based on the age, I am pretty sure the refrigerant is R-12, not R-134a. While R-134a was developed as a replacement for R-12, the oil requirements are very different. A refrigerant retrofit may be possible, it needs to include a change of the old oil to the new one.

I think you are in over your head. Time to get a pro to evacuate the system and charge it properly.

FWIW my system draws about 5 amps when running.

[redsky49]

Originally Posted by SV THIRD DAY

The gear (a gauge set and vacuum pump) will definitely cost you less than a refrigeration tech visit if you buy something cheap from say Harbor Freight. Refrigeration techs charge like Cardiac Surgeon these days. However, without the info and skills to go along with that gear...are you just spinning your wheels? It depends on your comfort level and willingness to learn. The problem I see is that very few Refrigeration Tech actually know what they are doing and will use your project to learn as they go. Given that, I would rather YOU be the one learning and then have the gear to self-service your own equipment. If could just be a simple vacuuming down and recharging is all you need which isn't rocket science.

Easy for you to say

However, for most boaters this will be a challenge:

In my opinion, the affordable 12V compressors are pretty chintzy, i.e. junk. Might work, might not. If you have 120V you are probably better off. Costs go up appreciably, though.

Where and how to obtain the correct refrigerant? Requires certification in many cases. What about refrigerant recovery? More equipment? How will users even identify the proper refrigerant or replacement? Where to find R-22 for example?

A set of gauges, either 3 or 4 valve is needed. Maybe Harbor Freight if you are willing to measure vacuum in inches, but a digital micron gauge would be more accurate, especially if chasing a leak.

With small systems it is very difficult to charge by weight as the refrigerant charge is often only a couple ounces. Doing it by the gauges works but assumes some skill. Overfilling is just as bad as underfilling.

The depth of vacuum and the length of time it is held is important. Really deep - 28 inches as a minimum - and held for overnight (or at least several hours) is critical. How well will Harbor Freight do on this?

Many systems are made so that connecting gauges is difficult. These systems are not made to be user friendly for repair.

If you have a component failure, recharging will do you no good. How do users diagnose their system?

I respect your experience and opinions, but suggest that boaters consider their options, and that includes a qualified refrigeration mechanic. Or, if nearby, give you a call!

You do this for a living. Most boaters don't.

Just my opinion. See you in Melbourne in November?

[Hud3]

I had a similar setup. It would run hot when we were in the islands. I installed a 12V fan to blow on the compressor, which was in a cockpit lazarette, and that helped quite a bit. Might not solve your problem, but it can't hurt to try.

[pcmm]

Originally Posted by JimsCAL

I have that system on my 1985 Cal 33. Based on the age, I am pretty sure the refrigerant is R-12, not R-134a. While R-134a was developed as a replacement for R-12, the oil requirements are very different. A refrigerant retrofit may be possible, it needs to include a change of the old oil to the new one.

I think you are in over your head. Time to get a pro to evacuate the system and charge it properly.

FWIW my system draws about 5 amps when running.

Its def a R-134 system. the copper lines have yellow R-134a labels on them. I think I need someone to draw a vacuum on it and recharge it properly. I'm also going to replace the dink little heatsink fan with a nice 120mm computer fan with similar current draw

[skipgundlach]

After you get fully redone (long vacuum and then recharge), you can twiddle the charge by watching your frost line. If it gets outside the box, you're overcharged, and vice versa.

Rich will cringe, but if you make sure you purge your supply line (the one from the can; you'll have to find an R12 hose and adapter for the can if you don't have a gauge set), you can put in a squirt (1-2 second open and close the valve on the can) or bleed (loosen the hose or depress the tire valve the same way) and get to the proper charge.

But cooling that compressor, particularly on an older one, will also cool the tiny filter/drier next to it; that has killed many systems, mine probably included.

The controller on the compressor has a fan connection; get splitters for the push-ons, and keep the little one on the heat sink, but add your big computer fan.

IF you haven't had a foul introduced (which could eventually kill your system due to the capillary tube nature of it), that will help avoid the usual death of older systems which have worked perfectly for years, get laid up, and then die.

My system has several threads on CF. You could look at some of the ones which happened in 2012 for amplification of the subject...

[Anna Sail]

Originally Posted by pcmm

That's art of the problem. I can't find much on the frigobost systems for the charge information and I don't have the equipement to pull a vacuum. I would need gauges and avacuum pump for that. Question is, is that equipement more expensive than having a tech in to fix it? I have no problems tackling it if I can get the gear at a reasonable cost.

Have you tried looking at Coastal Climate Control - Marine Refrigeration, Air Conditioning, Systems Monitoring, Solar Panels and more! in Refrigeration>troubleshooting for information, in particular, Frigoboat info?

The reason you don't find a dearth of info regarding charge information is that it's a controlled substance. Trained techs have the info, plus the techs who think they're trained, unfortunately, and think they can apply what they've learned about refrigeration expansion valve systems and car air conditioning systems to a 12v capillary tube system. Three very different beasts!

As much as it's tempting to DIY your system, it may be wiser to learn all you can and then call in that tech and keep your eyes on what s/he is doing to ensure they are truly qualified.

Richard is correct regarding your fan idea - keep the tiny fan on the heat sinc, but go ahead and add a secondary fan to move the air in where ever your compressor is installed, assuming you've installed it in a closed environment. If it's in the engine room, don't bother. You don't say how hot the compressor gets... 100 degrees F is fine. 130 degrees F is not. That means it's working too hard. Perhaps it's overcharged and is now trying to compress liquid instead of gas R134a. The frost line will answer that question no gauges necessary.

[Dougtiff]

I have the same system, what everybody is missing is that it's a KEEL COOLER, which means the KEEL COOLER is cooling the system, DUH !

[wrwakefield]

PCMM,

I don't have direct advice for how to troubleshoot your system, but you have received much of that already.

In times past when I had refrigeration issues and could not query others or summon technicians, I consulted Nigel Calder's book: Refrigeration for Pleasure boats: Installation, Maintenance and Repair and so far have been lucky enough to find the answers there...

Another volume that I think is worthwhile in my onboard DIY library.

In case this is of interest.

Cheers! Bill

[skipgundlach]

Originally Posted by Dougtiff

I have the same system, what everybody is missing is that it's a KEEL COOLER, which means the KEEL COOLER is cooling the system, DUH !

Not so much. The issue at hand was a hot compressor - which can lead to other problems. The location and ventilation of the filter/drier is from hunger...

[Cool Runnings]

Be very careful with the 134a that you select to recharge. Be sure that it does not contain a leak stopping agent as this can plug the capillary tube.