Marine Refrigeration

Frequently Asked Questions                                                                                   

Q:  What extras will we need to complete the project?

A:  The OzeFridge systems are complete less the eutectic solution*. To install the system you will need a helper, some hand tools and a hole saw to drill a pipe entry hole through the cabinet. These items are listed in the installation manual. ( *The tank / plate is sent dry to reduce freight cost and make fitting easier. The eutectic solution is readily obtainable.)

Q:  Can I install the OzeFridge system myself?

A: Anyone that can use basic tools should be able to install this system. With the help of an assistant and the installation manual supplied, the OzeFridge should be in and running in about 2 to 3 hours. If preferred we can recommend a local refrigeration company to supply and install your new system.

Q: What about the gas and pipes?

A: The system is pre-gassed. Simply locate the tank (or plate) and the refrigeration unit, couple up the two pipes, open the valves and you are ready to power up.

Q: But what if I still have questions about the installation?

A:  At OzeFridge or Marine Direct we are only a phone call away 24/7.

Q: Where should I locate the Refrigeration Condensing Unit?

A:  The need for the condensing unit to effectively dispose of the heat it removes from the cabinet is paramount. Locate the unit where air entering the condenser at the rear is not air that has exited the fan area.  Do not locate the unit in a cupboard, under the bunk etc without separated air in and air out openings. 

Q: Is it better for the refrigeration unit to be air cooled or water cooled?

A:  Properly sized air cooled systems are adequate and more power efficient for most applications, however there are many situations where water cooling is necessary. Air cooling alone may prove best during cooler months with the addition of water cooling during hotter periods. Water cooling is essential if the system is to be located in an unventilated enclosed area.  

Q: We are cruising the tropics soon, do we need water cooling for our refrigeration unit?

A:  Not necessarily, but the OzeFridge system is both air and water cooled, so if needed just add water!

Q: Why are OzeFridge refrigeration units supplied standard with both air and water cooled condensers? 

A:  This allows the OzeFridge system to suit a wider range of application and performance requirements without tacking on more extras later. Most of our clients will only use the air cooled function but the option is there for boosting the systems capacity if conditions change.

Q: If I use the optional OzeFridge condenser water pump, how does it work?

A:  The model P4 optional pump kit is powered from a circuit standard on all of our refrigeration units. You simply connect the water pipes to the condensers two 10mm nipples, connect the pump power lead to this refrigeration unit circuit and switch the 'plus water' switch on. When the compressor runs, the pump will run also. Switch to 'air only' if automatic pump is not required.

Q: What happens if there is a blockage in the water line?

A:  The pump has a pre-set pressure switch cut off. 

Q: Why does OzeFridge emphasize the importance of good condensing?

A:  The condenser disposes of the heat removed from your cabinet thus lowering it's temperature. The quicker and more efficiently this happens, the sooner the system switches off. Australia's environment can be harsh and we have seen many under condensed European systems fail here because their engineering does not suit our conditions.

Q: We have a motor driven Eutectic system but would like the benefits of constant refrigeration without running the motor specially when we are in the marina.

A: If your motor drive system is ok simply add an OzeFridge C150/ P50-40 eutectic plate system to your cabinet and operate each separately as appropriate.

Q: How does the Danfoss BD50 compressor compare to others?

A:  The Danfoss compressor is world renown for performance, efficiency and reliability. 

Q: I heard about a company that uses a 240 volt Chinese made rotary compressor with a 12 to 240 volt inverter and they say it is two times more powerful than the Danfoss?  

A:  Really, sounds like smoke and mirrors!  Here are the actual figures on each compressor:  The Danfoss BD50 pumps 8750cc's per minute while consuming 5.2 amperes per hour of running at a minus 23c evaporator temperature. (8750 is: recommended maximum speed = 3500 RPM x 2.5cc capacity)  Similarly the Chinese made rotary 309 pumps 8652cc's per minute while consuming a stated 8.00 amperes per hour of running. (8652 is: inductive speed at 240 VAC = 2800 RPM x 3.09cc capacity). So it appears that not only does the rotary compressor pump less but consumes greater than 50% more battery power doing so! (Perhaps they meant two times greater battery power consumption!)

Q: Does the OzeFridge system use less battery power?

A:  The Danfoss powered OzeFridge system consumes far less battery power than any rotary compressor powered system. We openly challenge other manufacturers to try matching our systems economy.

Q: Can I run the system from 240 volt generator power when available?

A:  Absolutely, both the 12 a 240 volt supplies remain connected at all times. When 240 volts is available the system automatically uses that as a priority and as a bonus will 'float' voltage back into the battery's) ensuring that they are always topped up ready for departure. 

Q: Why is the OzeFridge refrigeration unit inside a stainless steel case?

A:  The case allows positive air movement over the compressor as recommended by Danfoss and through the condenser while also providing component protection, mounting and tidiness.

Q: Can I boost the refrigeration speed?

A:  Yes, with the units speed switch, select automatic or +40% modes. The +40% mode over-rides the Danfoss compressors automatic speed adjustment and allows the compressor to run at maximum speed.

Q: Where is the refrigeration gas stored?

A:  All OzeFridge systems are supplied gas charged. The required amount of gas is stored inside the refrigeration unit. After coupling the pipes, two valves are opened to allow the system to operate. (All explained fully in the owners manual.)

Q: What about any future servicing?

A:  The OzeFridge system is similar to a domestic refrigerator, simple and reliable. Should repairs be required any competent refrigeration mechanic can quickly connect to the external service valves for system analysis without welding or fitting additional devices. If preferred, the system valves can be closed off isolating the gases and the refrigeration unit sent to OzeFridge for repair.

Q: Is the refrigeration gas safe?

A:  The refrigerant gas used is the environment friendly R134a. The quantity is less than 260 grams. (About a Coke can full!) 

Q: Why does OzeFridge only manufacture eutectic systems?

A:  The eutectic system although more expensive initially, has benefits that make it by far the most suitable refrigeration method where power supply is limited, erratic and varied. (See our page 'Eutectic Systems')

Q: How can I estimate how often a system will run to re-freeze the eutectic solution in my cabinet?

A:  The easiest way is to use a container similar in size to the eutectic tank / plate you intend using, (our small tank = 4Lt, large tank =9 Lt, large plate = 6Lt). Fill the container with water and place in your deep freezer for at least a couple of days. Then put this frozen container high up inside your empty boat cabinet and see how long it lasts before totally thawing. This will give a guide as to how long each freeze / thaw cycle of a eutectic system will be. For example, if the test lasted 24 hours then your system will run one freeze cycle per day. Each freeze cycle will be 2.3 to 4.5 hours long and consume a total of approximately 8 to 23 amperes.  

Q: Why is the OzeFridge digital 'Sure-Thaw' so beneficial?

A:  Only OzeFridge has the 'Sure-Thaw' digital controller that guarantees proper freeze and thaw on each and every cycle.  Without this unique control feature the systems function would be erratic with no means of ensuring that the eutectic benefit is operative. 

Q: Does the 'Sure-Thaw' controller lower the power consumption?

A:  Absolutely, with proper eutectic phase-change guaranteed on each cycle by this unique controller, unnecessary compressor running is eliminated and run periods are optimized.

Q: Is it better to use the larger tank / plate?

A:  Yes, if practical, the larger eutectic capacity provides greater hold-over and is more efficient on power consumption.

Q: Why doesn't OzeFridge weld the stainless steel eutectic tanks to the base plate?

A:  Our eutectic tanks & plates are bolted together using a flexible seal. This eliminates fractures that can occur in welded joints caused by the constant expansion and contraction. 

Q: Why are eutectic refrigeration systems so efficient on power?

A:  Refrigeration systems are more efficient when heat rapidly saturates the evaporator, and as the eutectic evaporator is in a liquid it can rapidly absorb temperature. By comparison aluminum plate evaporators cooling the air run at much less efficient temperatures where the refrigeration systems coefficient factor is very low. (Put a hot can of drink in ice water and another on the shelf of a fridge at the same temperature. You will be drinking the one from the ice water ten times sooner!) So not only is the system operating in much more efficient conditions, it does the job so much quicker and with the eutectic hold-over, runs much less often. An aluminum evaporator plate system will typically cycle say 10 minutes on 20 minutes off. (Two cycles per hour or 48 cycles per day while the Eutectic system runs once per day or twice in hot conditions.)

Q: But aren't aluminum plate evaporator systems cheaper.

A:  Yes they are, but try buying one with a decent warranty against gas leaks developing. The aluminum plate is soft and the refrigeration gases can easily be lost if the plate is punctured or corrodes when the anodized coating is scratched. Such happenings are common and cause contamination of the entire refrigeration system which can render it virtually useless.  While costing less initially they will forever consume much more battery power and prove to be not cheap in the long term.

Q: How do I work out the capacity of my cabinet in liters?

A:  To establish a cabinets capacity multiply the width x depth x height in centimeters, then move the decimal point three digits left to give the result in liters. 

Q: How important is my cabinets' insulation?

A:  The thickness and quality of the cabinets insulation is most important. A refrigeration system removes heat from the insulated cabinet causing the cabinet and stored product's temperature to be lowered until the required temperature is reached and the refrigeration unit is switched off.  Now how long the refrigeration remains off for is determined by how effective the insulation is at resisting heat trying to penetrate into the colder interior. The thickness, quality and seal of the insulation are the important factors. 

Q: Why do you recommend thicker insulation in the base of the cabinet?

A:  Heat penetrates in a rising manner. Therefore the shortest way for it to penetrate a cabinet is upward through the base, secondly on an upwards angle through the walls and least likely through the top. We recommend at least 100mm of high density urethane for the base, 75mm for the walls, while  50mm is adequate for the top. Add 50% for freezer cabinets. 

Q: What insulation material could I use for my new built-in galley cabinet?

A:  Generally refrigeration grade high density urethane slab or two mix high density urethane poured insitu is quite satisfactory specially if thickness is as much as practical and the insulation is installed with NO voids and is properly sealed.

Q: What are common problems with older cabinets?  

A:  A common cause of heat gain into a cabinet is delaminating. This is where the insulation has become detached from the cabinets inner or outer liner. Air can fill the vacant area depositing water where the insulation should be rendering the insulation useless. To check, first empty the cabinet then tap the insides to locate any looseness. Check the outer cabinet for sweating or water dripping stains. If there is a problem then it may be easier to rectify before fitting refrigeration.

Q: How do I check my lid or door seal for air leakage?

A:  Place a torch inside on a dark night and check for any light escape areas. Remember, every bit of heat that enters the cabinet has to be extracted by the refrigeration system!

Q: My cabinet is difficult to clean. Are there any tips?

A:  After cleaning, thoroughly dry and warm the interior if possible. Use some old style floor wax to coat the cabinets entire interior. Remove excess wax then operate cabinet. This will make the next cleanout much easier, reduce the possibility of odor build-up and restrict any moisture from entering insulation through any defect in the interior seal.

Q: So where are these OzeFridge systems made? 

A:  OzeFridge products are engineered and manufactured in Australia to Australian Standards. (We do not rebadge Chinese products and infer that they are made in Germany!)

Q:  What advice do you offer when selecting a system?

A :  Be informed and purchase a system that is appropriate for the application. Be aware that some companies offer systems bit by bit, so get quotes for ALL that is needed for a complete system and avoid paying through the neck for add-ons later that after all, were essential for the system to operate correctly in the first place.

Q: We priced a comparable imported system recently, so why do OzeFridge systems cost so much less?

A: We are the actual manufacturer with a more direct distribution to you. Our products do not suffer from the numerous mark ups that the imported models have built into their pricing. The OzeFridge system is arguably superior yet costs less than any other similar systems, in fact half the cost of some imports! 

Q: What do I get when I purchase an OzeFridge System?   

Stainless Steel housed Model CU150  condensing unit including:

• 12 & 240 volt refrigeration operation.
• Powerful Danfoss BD 50 compressor.
• Air & water cooling condenser. (Use as either water cooled or air cooled or both)
• Digital temperature monitor / read out via LED.
• Digital sure-thaw temperature controller.
• Compressor speed selector switch.
• Condenser air or water cooling selector switch. 
• 120mm automatic condenser fan. 
• External refrigeration and electrical couplings.
• External refrigeration Schroeder service valves.
• Gas charged with R134a refrigerant. 
• Condenser pump power connection via internal relay. (For optional pump if required)
• Eutectic tank or eutectic plate that best suits the application. 
• 2 meters of insulated refrigeration lines with sealed connections.
• Installation / operators manual.
• Local support and 1 year warranty