Running my Unit

Q: What can I do to make sure I am running my unit as efficiently as possible?

A: There are several easy steps and checks you can take to ensure you are keeping your fridge in good working order .

1. Clean the refrigerator coils: Refrigerator condenser coils are located in the rear of the refrigerator. You can simply vacuum the vents and coils to clean them. Dusty coils have to work harder to cool down the interior and contents of the refrigerator.

2. Check the gaskets for proper air seals: The gaskets are the seal that keeps in cold air in and the room air out of the refrigerator and the same for the freezer. The gaskets should last the life of the refrigerator if properly cared for. All you need to do to keep them in good shape is wash them down with soapy water. You can test the condition of the gasket by the “paper test.” You should not to be able to slide a piece of paper between the rubber seal and the frame of the refrigerator (or freezer). If the piece of paper slips between the seal and the frame, the seal is not tight enough and the gasket requires replacement.

3. Defrost freezer: For optimum performance, maintain refrigerator temperature between 35F and 40F. Freezer temperature should be kept between 15F and 20F. Freezers need to be defrosted on occasion for optimum performance. Those without an automatic defrost capability, should be cleared of ice and frost that has built up on the evaporator plates. Ice buildup inhibits the freezer’s ability to maintain proper temperature and causes the freezer to work harder than necessary to compensate. Do not allow the frost to accumulate to more than ¼”. When it reaches this level, it is time to defrost the freezer. Please do not use any sharp implements to remove frost from the unit. This can cause irreparable damage to the evaporator plate. Please follow the defrost steps above section.

Q: What are your top energy saving tips for refrigerators and Freezers?

A: Energy Saving Tips For Refrigerators:
1. Minimize moisture by keeping food covered and containers shut. Moisture can cause the compressor to work harder unnecessarily.
2. Replace paper wrappings on items in the refrigerator with aluminium or plastic. Paper is an insulator and will prevent from cooling food items properly.
3. Consider the location of your refrigerator and / or freezer. Do not position them in direct contact with hot appliances as this will make the compressor work harder.

Energy Saving Tips for Freezers:
1. Keep in mind, a full freezer will perform better than a empty freezer.
2. Keep the doors closed as much as possible and make sure they are closed tightly.
3. To help minimise power consumption, it is a good idea to pre-freeze products that are going in the freezer section. It takes 133 times more power to freeze a product than it takes to cool a product.

Thoughts to Keep in Mind:
1. The colder the fridge and the freezer the longer the run time and the more power consumed.
2. For an efficient power versus temperature many users find setting the fridge for 40-42 and the freezer from 20-25 will extend your time with out recharging the batteries.
3. In mobile applications where the unit is running from stored energy in the battery it is desirable to use as little power as possible. This allows you to dry camp or stay at anchor for extended periods of time.
4. Our units are designed to work in variable ambient temperatures from 60 °F to 100 °F range while in transit or stationery. Our units will run on an incline of up to 30° angle in any direction.
5. The power to run our units is supplied from your battery system in 12-14 or 23-28 VDC

Q: What run time is the most efficient?

A: Nova Kool units are designed to run in the most efficient manner. The compressor size and speed is matched against the evaporator and condenser to minimize the overall power consumption.

We purposely design our units to run longer, but at a lower amperage draw. We do this for two reasons. Firstly because every time a compressor starts up it momentarily draws 4-5 times the running amperage. Secondly, every time the compressor starts up it is pumping vapor. It takes 15-30 seconds for the compressor to pump the refrigerant through the condenser which in turn changes the vapor to liquid which then feeds the evaporator (cold plate). So for the first 15-30 seconds of every run cycle the refrigerator is setting up to cool but is not effectively producing cooling at the plates.

Since batteries are rated in amp hours it is important to do the job with the least amount of amperage as possible. Run time does not equate directly to more consumption. To compare power usage you need to take the run time and multiply it by the amperage that the fridge is drawing when it is running. An example is our SECOP BD35f can draw 2.2 – 6.5 amps by changing the speed. It is best to set it the amperage at the lowest value and let the unit run with the minimal cycles to produce the best efficiency.

Q: What can I do if my run time is too long?

A: This is due to a high ambient temperature, a large size of box, and not enough insulation or combination of. (especially with LT ice box conversion kits)

The solution is to run the compressor at higher speed. To do so, you need a resistor installed in line of thermostat circuit. The thermostat is connected between the terminals C and T on the SECOP control module. Without any resistor in the control circuit, the compressor will run with a speed of 2,000 rpm when the thermostat is switched on. Other fixed compressor speeds in the range between 2,000 and 3,500 rpm can be obtained when a resistor is installed to adjust the current (mA) of the control circuit.

Q: Why is Ice Cream so hard to keep firm?

A: As far as ice cream is concerned it is essentially a solution of milk (which contains water, lipids, proteins, and lactose) and refined sugar. With so many solid substances dissolved in water, we would expect the freezing point of ice cream to be below that of water. But, it's slightly more complicated than that.

Cow's milk naturally freezes at a temperature of approximately -.5°Centigrade, or 30° Fahrenheit which is not much lower than the freezing point of water. So how is it possible that ice cream can still feel "unfrozen" at temperatures far below -.5°C or 30° F?

The reason is that as the water component of the ice cream solution begin to freeze, it isolates itself from the rest of the solution by forming pure ice crystals (which are readily observable in ice cream). As a consequence, the relative concentration of the solid substances dissolved in the remaining liquid solution increases, simply because there is less liquid water left available for the solutes to dissolve in. The left-over water can then only freeze at a much lower temperature; when it does get cold enough to do so, the concentration of the solutes goes up even higher, again, because there is less liquid water left.

You can imagine that as the ice cream gets colder and colder, the concentration of the solutes continues to increase as water is progressively removed from the liquid solution as it freezes, thereby greatly depressing the freezing point of whatever amount of liquid is left. The ice cream eventually becomes a mixture of frozen crystals and a relatively smaller amount of unfrozen, liquid solution which gives it a soft feel. Below about -25°C, or -14°F ice cream is stable for indefinite periods without danger of ice crystal growth; however, above this temperature, ice crystal growth is possible and the rate of crystal growth is dependent upon the temperature of storage. This limits the shelf life of the ice cream.

Nova kool freezers are design to keep frozen ice cream for a short period of time at temperature 15° to 20°F or -9° to -7°C.

Why does my freezer frame condense in some ambient conditions?

A: This is due to the temperature of the frame lowering to below the dew point of the air.

Solution: The solution is to run the freezer unit a little warmer. This can be done by adjusting the thermostat to a warmer setting. The coldest setting is 7, the warmest setting is 1.

On some models we supplied a thermostat desensitizer to allow the freezer to go to a lower temperature. This is a plastic straw that goes over the thermostat capillary tube before it is fastened to the evaporator plate. To allow the unit to run warmer you can remove the thermostat capillary tube by lifting the two tabs that hold the capillary tube to the evaporator. Pull the straw off the capillary tube and discard. Place the capillary tube back under the two tabs on the evaporator and press tabs against the capillary tube and the evaporator to make firm contact. By doing this it will run the freezer at a warmer temperature.
The freezer is designed to run at 16°f and -10°c

what should the Temperature Difference between the Fridge and Freezer be in my 2 Door Unit

The fridge and freezer run with approximately 20°F differnce from one another in a 2 door, single compressor unit. For example if your fridge is running at 40°F (4°C) then the freezer should be around 20°F (-7°C) - subject to application.