Frigoboat K50/Danfoss BD50 fridge problem

[Sputnikus]

Hi,

I have been combing the forums for help with our fridge problems. We found some useful information, but nothing that reflects our problem exactly (of course). We have a K50 Frigoboat with a BD50 compressor, keel cooled.

We noticed that only half the back was frosting. After a recent defrosting, we had a technician come out to look at the fridge. He measured only 1 pound of suction pressure, diagnosed a leak (didn't find it) and added refrigerant (r134a). Fridge frosted fully initially. Leak was not found, we want to get to a better location to do so, because we need to cut furniture apart for access.

Yesterday (3 weeks later) we noticed the fridge was not cooling well anymore and only 25% of the back was frosted. We have gauges onboard. The suction pressure read above 10 psi. Current sea temperatures are 25C. We turned the fridge off thinking the tech overcharged it. A local repairman came to check and removed some refrigerant. Shortly thereafter it wouldn't cool at all.

We have had it recharged again, this time it was reading 3 psi suction/185 psi head pressures after running for 4 hours. The frost covered 70% of the back, clearly not coming anywhere close to the compressor. Thermostat is set to middle setting. Does this sound like we have a blockage? We have had several techs on board and none of them has experience with this kind of fridge. What should I tell them about appropriate pressure? In a separate thread Richard Kollman recommended 6-8 psi within 20 minutes of starting the unit, then the pressure should drop to 3 psi or so after around 4 hours. Does this sound about right? Or should we just keep adding until the entire back has frost? Or is 175 head pressure way too high?

Thank you!

[Richard Kollmann]

The failure pattern you describe is not an isolated problem and Frigoboat in the US hopefully is trying to resolve it. They have retrofit items of installing missing filter and installing an inline fan cooled condenser but these need to be installed before condition gets as serious as yours.

The best advice I can give is to contact Rob at Frigoboat USA as he may offer a current solution other than buying a completely new system. Wasting money on service technicians is not the way to go.

[Sputnikus]

Thank you Richard.

The latest tech did the following: remove some refrigerant. Fridge off for 1 hour, helped along by warm water along inside back to come to room temp.

Started fridge with thermostat set to max. after 10 minutes pressures are -11/115 no frost on back, a little sweating in a corner.

Added refrigerant to get to 7 psi suction pressure, by 15 minutes past start.

At 30 minutes half the back had frost, low pressure was 6-7, high was 200.
After 55 minutes, frost on 5/6 of back, low pressure 5, high pressure 190.

I hear you about money wasted on techs, but what choice do we have.... we need something that works ok to get back to civilization....

I will contact Frigoboat as you recommend on Monday maybe they have another idea; I assume frigoboat US is the same as VECO/Coastal Climate Control out of Maryland? Nonetheless, we're hoping this latest fix will get us through the next 6 weeks until we are back on the US mainland.

Our frigoboat freezer works fine.

Are there other brands you recommend that are more reliable (in case we need to replace)?

[Richard Kollmann]

All of these failures seem to fall into a similar pattern of 4 to 5 years old and refrigerator in operation several months a year in warm seawater. When evaporator cooling begins to reduce it is believed to be loss of refrigerant do to leaking line connectors and enough refrigerant is added to increase low and high pressure. Low range pressure for a refrigerator must be 5 to 10 psi depending on capacity of evaporator and its refrigerant expansion device. If increasing refrigerant volume to achieve correct low pressure on this type system causes high pressure to exceed 130 psi it must be assumed that refrigerant flow is restricted somewhere or keel cooler is not efficient.


Sputnikus, You reported this condition confirming I believe is another Frigoboat system failure:
“Started fridge with thermostat set to max. after 10 minutes pressures are -11/115 no frost on back, a little sweating in a corner.

Added refrigerant to get to 7 psi suction pressure, by 15 minutes past start.

At 30 minutes half the back had frost, low pressure was 6-7, high was 200.
After 55 minutes, frost on 5/6 of back, low pressure 5, high pressure 190.”



In the past when it was finally determined that refrigerant blockage was most likely in capillary tube Frigoboat dealers advised boater to replace evaporator assembly. New evaporator turned out to be a temporary fix and blockage happened again. Then because refrigerant quantity is so critical on keel cooler models money was expended on a number of service calls. Next came the blame game. And warnings about running a keel cooler system when boat is out of water. Leaking refrigerant was caused by O ring seal failures. Maybe restriction of cap tube is wear partials from compressor. Why is it systems other than Keel Cooler models do not have these types of failures.

When running compressor at high temperatures as this system does will cause failures. Increasing high pressure even more will increase failure rate.

[Sputnikus]

Thank you again. It is what we feared. We will call frigoboat and go from there.
Any other keel-cooled systems that you recommend that do not see this pattern of failure?

Thank you

[Richard Kollmann]

After working on this problem for several years I hope that there is still a chance that Rob at VECO/Coastal Climate Control US and Frigoboat in Italy has a better solution to offer than again replacing another complete system.

There are no other water cooled friendly systems for a Danfoss BD compressor that I know of.

[skipmac]

Originally Posted by Sputnikus

Any other keel-cooled systems that you recommend that do not see this pattern of failure?

Thank you

Hi Sputnikus

Are you sure you really want or need a keel cooled system? I installed a Frigoboat air cooled system in my boat. BD50 compressor in a pretty large box, over 9 cu ft including +/-2 cu ft of freezer.

I have not yet gone cruising with the system but ran it for a week last August in Florida when daily temps reached 95 F and was quite happy with the overall power usage.

[onestepcsy37]

ten years ago, when i bought her, i replaced the water cooled system that came on my 1979 boat. although i know nothing about working on refrigeration it was plainly obvious that the water cooled system was too complicated - it had too many 'parts'. put in an air cooled adler barbour. has worked flawlessly for ten years in florida/bahamas.

i installed it inside the cabin but with good airflow into it. after reading richard kollmann i added a computer muffin fan that blows directly down on to the control module and compressor whenever the unit is running. the hot air exhaust goes directly into the engine compartment so no hot air blowing in the cabin.

[Sputnikus]

Our 2 biggest issues with air-cooled systems are that they are, in our experience, noisy and produce heat. We have an ice-maker in the cockpit that is air-cooled and when we run it, it is very, very noisy.

[skipmac]

Originally Posted by Sputnikus

Our 2 biggest issues with air-cooled systems are that they are, in our experience, noisy and produce heat. We have an ice-maker in the cockpit that is air-cooled and when we run it, it is very, very noisy.

Both certainly concerns however I think concerns that can be addressed. The heat can be minimized by locating the compressor unit in an area where the heat goes out of the cabin and by ducting the air flow. Note even a water or keel cooled unit puts some heat into the area around the compressor since the compressor unit itself gets quite warm.

My new Frigoboat BD50 air cooled is certainly not silent but not loud in my opinion. I think the noise of the refrigerant gurgling through the evaporator inside the fridge is at least as noisy as the compressor/fan unit.

[a64pilot]

My compressor is in the Lazarette. I've never heard a sound

[onestepcsy37]

yes, mounting the unit is probably key to noise and heat problems. sometimes it just isn't possible to mount it in an ideal location. in our case we were able to duct the warm air discharge straight in to the engine compartment and baffle the intake to reduce the noise, which is not very great in any case.

but the great advantage of using air over water (more trouble free) makes it worthwhile to occasionally hear the hum of fridge doing it's thing. listen to richard kollmann, he's been doing this a long long time....

[Sputnikus]

Thank you to all of you who posted. We are limping along with the keel cooled system that requires recharging regularly and is most likely still blocked.

When we are back on the mainland we will seriously evaluate an air-cooled system. Hopefully I will remember to come back and give an update for posterity.

[Richard Kollmann]

If adding refrigerant regularly keeps evaporator frosted correctly and does not increase amperage, compressor heat and high liquid pressure then solution would be correcting leak and deep vacuuming system.

Problem is your earlier report was high amperage and high pressure that pointed to contaminated refrigerant flow, a typical pattern of a Frigoboat keel cooler system failure.

[Sputnikus]

Hi Richard,

In order to get good frost coverage (80%) the high pressure goes up to and slightly above 200. This is required to get the low at barely 6 in 20 minutes.

We will try the vacuuming and leak detection, but I am not hopeful given your previous comments re: very high/low low simultaneous pressures.

Thanks again....