The commercial ice machine represents a substantial investment of capital. A business requiring one or more commercial ice machines likely has plenty of money and business growth plans pivoting on the continued performance of their equipment. Customer satisfaction and energy consumption (expense) are real issues alongside the technician’s technical problems. For these reasons, before changing the ice machine installation piece by piece, it is essential to evaluate the overall aspects of the job ahead.
It should be noted that business owners and managers are (by necessity) driven almost entirely by income and expense motivations. Who wants to spend thousands when they can spend hundreds and save some money for a rainy day?
If changing a single piece, such as the ice machine head or remote condenser, with an exact replacement, performance is not likely affected alongside proper installation technique and best practices. On the other hand, when exact replacements are not available and mixed models, and manufacturers are used, performance, service life, ice production, and energy consumption are all adversely affected. Consider this a constant when taking this pathway. Also, consider that beyond the compatibility of components, the condition and sizing of the refrigeration lines are integral to deciding how to proceed to restore onsite production.
Technicians who encounter an ice machine with apparent modifications to the original design should evaluate the complete installation before correcting or making repairs. It is possible that any deficiencies cannot be corrected without starting over with a new complete ice machine.
Let’s explore some pre-replacement questions that directly affect the business decision supporting either the repair or the replacement pathway.
Refrigeration System-Retro Fit and Change Outs
Refrigerant blends are rapidly changing, making mixing old and new equipment less plausible on any level. Make consideration of the following issues before starting any major retrofit work.
Is the replacement head or condenser an exact replacement match? If not, carefully evaluate the currently installed refrigerant and electrical controls’ location and existence compared to any planned system changes. A mix of old and new installations provides a trap for incompatible refrigerant controls that cause a reduction in performance or complete failure of the installation. This type of installation error is hard to locate and repair after the installation is thought to be complete. For instance, the location of the condenser pressure regulator (CPR) varies between manufacturers, from the ice machine head to the condenser. Technicians have been known to replace equipment so that both units inadvertently have a built-in CPR, leaving behind erratic systems with inadequate ice production and incredibly high energy and water bills.
Is the refrigerant blend necessary for the replacement head or condenser the same as the previous refrigerant? In some cases, retrofitting is impossible, and a complete replacement of all units, components, and refrigerant piping is mandatory. Expansion valves, control valves, and pressure switches are all calibrated and built for predictable pressures and operating ranges based on the designed refrigerant. Changing refrigerant means that these remaining components lack calibration and are not suitable for the new installation. For clarity, the system will not perform well, if at all.
R-404A, R-134, R-502, or R-22 are common CFC, HFC, and HCFC refrigerant types commonly in use. Since 2014, unitary ice machines have also been designed using R-290 (highly refined propane), which is generically termed a hydrocarbon-natural refrigerant. R-290, although potentially explosive, works very well in systems designed especially for it. It should be noted that R-290 has been around a long time. The push to move out ozone-depleting refrigerants with a high (or any) Global Warming Potential (GWP) has moved up the adoption of natural refrigerants that include R-717 and R-744 is based on CO2 or ammonia, respectively.
Retrofitting CFC, HFC, and HCFC ice machine components between each another are poor practice. Refrigerant oil residuals remaining in the sealed system and changes to the refrigerant line sizes make this practice a strong candidate for poor performance and short service life.
Typical Example: A technician changes out only the ice machine remote condenser. Initially, the remote condenser required (for example) an R-12 refrigerant using mineral lubricating oil. The new condenser/remote unit with an updated refrigerant requires an oil charge of Polyolester (POE) synthetic oil due to new generation designs.
When the new mixed system operates, the POE oil behaves as a detergent and effectively cleans out the sludge built up in the existing refrigerant lines.
Shortly after the startup of the new condenser, the technician probably finds that the filter drier is Inevitably the oil in the compressor crankcase is contaminated, and the TXV inlet screen is restricted.
These restrictions in the drier or TXV screen result in a reduced capacity or complete failure altogether. Failures in this category usually revolve around the heart of the system, the compressor. Once the compressor has failed, the technician and the business owner are at the crossroads of repair or replacement. If the repair costs 50% or more of the ice machine’s replacement cost, more consideration should be made to replace it. An adage says the second compressor never lasts as long as the first compressor installed at the factory. The second compressor’s shorter lifespan is that the first compressor was installed in clean conditions using clean copper tubing and clean components. The second compressor being field-installed is dirty from the onset and prone to acidic accumulations that progressively corrode and dissolve, including the internal compressor pump components, electric motor, thermostatic expansion valve, and other refrigerant solenoid valves unique to the ice machine.
Refrigerant Lines
There are cases when the refrigerant line sets cannot be changed because they are embedded in a wall or other inaccessible areas. The reality check is that the job needs to be done right, not necessarily to accommodate the ice machine’s poor location. I know this sounds harsh, but if the only alternative is to make an installation that creates service life and performance reduction, why do it?
There are several options available in situations when the current location becomes unsuitable.
- Install a unitary (self-contained) ice machine without using a remote condenser.
- Relocate the remote condenser to accommodate a location that allows for routing of the refrigerant lines.
- Abandon onsite ice production altogether and arrange for quality ice deliveries.
Shown above is an example of system evacuation, and in this case attempting to clear out mineral oil from the existing refrigerant lines.
Refrigerant Oil Considerations
Refrigeration oil is often overlooked when it comes to servicing refrigeration systems. There are two primary oils used for refrigeration system lubrication.
- Polyolester oil (POE) quickly absorbs moisture, a condition referred to as hygroscopic. If the refrigeration system charged with POE oil has excessively been open to the atmosphere for longer than a few hours, changing the lubricating oil must be considered. POE oil does not dehydrate after contamination using any flush, evacuation, or nitrogen sweeps.
- Mineral oil containing wax tends to solidify due to moisture and acidic conditions, restricting the TXV and the liquid line drier.
If a compressor running burnout* occurs, consider a complete replacement of all refrigerant lines and equipment. Severely contaminated, the refrigerant oil, in turn, leaves a coating on the inside of the refrigerant lines and every refrigerant control component in the ice machine. The economic and technical feasibility of responsible repair is usually not reasonable. For as long as technicians have worked on refrigeration systems, they have fallen into this trap of repairing severely contaminated systems resulting from compressor burnout. Moreover, for just as long, technicians have caused intense customer dissatisfaction when the system fails in short order once more after expensive repairs have been made.
Changing the lubricating oil is a highly technical process that requires the removal of the compressor so that the existing contaminated oil can be drained and replaced with the correct amount of dry lubricant. If repair is the only available option, consult the factory service manual for the proper oil charge and the correct procedures on the particular model of ice machine undergoing service.
Production Check
After this discussion, it should become clear that your Grandfather’s ability to change only a single piece of equipment 30 years ago is no longer a relevant pathway to take. Before my Grandfather’s reference is taken negatively out of politically correct context, the author is a father, step-father, Grandfather, and Great Grandfather (thanks, Alexis).
After the installation is ‘complete,’ it is critically important to measure the ice production rate. Consult the installation guide on the manufacturer’s specific instructions to do so. If the ice production rate does not meet the anticipated production referencing the manufacturer specifications, then take the time to find out why. Note that the ice production rate measurement does not consider anything read from the refrigerant manifold gauges, only the amount of ice produced under the current conditions.
Conclusion
All things considered, mixing HVAC/R equipment has always been a terrible idea, similar in scope to mounting a Chevrolet engine to a Toyota transmission. In the age of influencers and bloggers, this has probably been done on YouTube, but I think we can agree it’s still a dumb idea and not a good solution.
*A condition where the compressor motor is failing and emitting soot (disintegrating) inside the refrigeration system while still running and pumping.
