What makes Emerson’s moisture indicator better? Early detection

The 3% difference.
What makes Emerson’s moisture indicator better? Early detection. The HMI’s patented wafer dial uses a three-step gauge to detect moisture at 3% relative humidity (RH) – giving you plenty of time to make necessary adjustments before any damage is done. Ordinary indicators use a two-step paper gauge that only detects moisture at 10% RH – a level that is more than enough for corrosive acids to build up and totally destroy a system.

Designed for today. Made for tomorrow.
The added moisture sensitivity of the HMI makes it ideal for nearly every refrigerant available – from HCFCs to new higher-pressure HFCs (including R-410A). In fact, the HMI is available with both ODF and SAE connections and is the only moisture indicator UL-approved to 680 psig. So even as your customers’ systems undergo mandated changes in the next few years, the HMI you install today will work with the refrigerants of tomorrow.

Built to last with a universal fit.
The HMI has an airtight, corrosion-resistant brass body with no o-rings or knife-edge seals for guaranteed leak-free operation. Plus it is heat resistant, so you can braze without having to worry about damaging the internal wafer dial. For installation, the HMI features solid copper fittings for easy, universal replacement of any brand indicator. Saving you time, along with your reputation.

Now you see it. Now you know.
Let’s face it, moisture indicators are almost always in dark areas with poor light. Which is why we gave the HMI a wide-angle, .71 square-inch viewing lens – by far the biggest in the industry. And with an easy-to-read tri-color-coded system, you’ll be able to read the dial even in low light.

Paper or plastic?
The HMI wafer dial is a molded disk that is significantly more durable than ordinary paper indicators. And it is more sensitive to lower levels of moisture (3% versus 10% relative humidity). In fact, the color in a paper indicator can actually wash out under wet conditions. Plus paper indicators are highly susceptible to damage from brazing during installation.

Protect your reputation with the HVAC/R technology leader.
When it comes to your HVAC/R systems, you have enough things to worry about. Your reputation shouldn’t be one of them. With Emerson’s HMI, you know your customers are getting a better indicator and you are getting a better warning system. After all, your reputation is worth it.

Lets look at the review from http://www.achrnews.com.

Earlier indication.
Better design. More reliability. The Emerson Climate Technologies Hermetic Moisture Indicator. Buy yours from our selected wholesalers.

HFC Refigerants and POE Lubricants - Part 3: How to combat water in the system [2]?

Another aspect of POE oil is the ability to keep more solid particles in suspension than Mineral oil. This is particularly important in retrofitted systems where pockets of solid contamination are now flushed from low flow areas and need to be removed before moving parts in the system are damaged. The filter-drier for POE oils needs to have increased solid particle holding capacity with minimal impact to refrigerant flow capacity or pressure drop.

The filter-drier should also have improved contaminate removal efficiency as well to ensure that all particles are captured the first time they enter the filter-drier. The ability to remove smaller particles is also advantageous. The EK series filter-driers provide a unique combination of these characteristics to provide outstanding filtration.

The filter-driers for use in HFC and POE oil systems must maintain the system dry and free of any acids that may have been generated. However, since water capacity is of primary importance the filter-drier should contain a higher percentage of molecular sieve than was required for CFC and HCFC systems. But molecular sieve alone is not sufficient since it has virtually no organic acid capacity. An organic acid removal desiccant must be used such as activated alumina to ensure low acid levels are maintained. In addition, the filter-drier should also have increased filtration capacity and efficiency.

The EK filter-driers provides the optimal combination of these properties to ensure the long, trouble free life of any air-conditioning or refrigeration system.

The moisture indicating sightglass must also indicate moisture level in the range of less than 50 ppm moisture. Also, it must be able to perform this function at the temperature of the liquid line on which it is placed. Many sightglasses cannot perform this function at all liquid line temperatures. This low level indication ability is necessary to ensure that the system moisture never exceeds the level at which organic acid formation starts. The HMI & AMI moisture indicating sightglasses provide this low level detection early.

HFC Refigerants and POE Lubricants - Part 2: How to combat water in the system [1]?

Refrigerant systems must be dry internally because high moisture content can cause ice to form in the expansion valve or capillary tube, corrosion of bearings, reactions that affect lubricant / refrigerant stability, or other operational problems. As with other components, the refrigeration lubricant must be as dry as practical. Polyolesters [POE] usually contains 50 to 100 ppm moisture in normal manufacturing. This amount may increase between time of shipment from the refinery and the time of actual use.

POE oils are quite hygroscopic in its properties.

Monitoring

To combat the detrimental effects of water in HFC and POE systems it is imperative to hold moisture levels as low as possible. It is generally accepted that water level must be maintained less than 50 ppm in the refrigerant and the same for the oil. Monitoring is therefore necessary. In order to monitor system water level a moisture indicator must be used that can sense changes in moisture in this ppm range.

Many commercial sightglasses cannot indicate a change at this level in liquid lines that exceed 100degF or 38degC. This means that harmful organic acids may be attacking system components while the indicator is showing 'dry'. The HMI and AMI moisture indicators have unique element that has the ability to change colour at low ppm levels so that proper action can be taken before any system components are damaged.

Filtering

Because POE lubricants are quite hygroscopic, when they are in a refrigeration system they should circulate through a filter-drier designed for liquids. A filter-drier must be installed in the line carrying liquid refrigerant or in a line returning lubricant to the compressor. The desiccants will remove some additives in the lubricants. It was necessary to redesign standard 'catch-all' filter-driers for increased water removal capacity to achieve these low moisture levels. Since no system is entirely devoid of water upon startup some organic acids will be generated and must be removed.

The desciccant formulation for the EK and UDK series of filter-driers was designed to provide the optimal mix of water capacity and acid capacity to ensure that both harmful contaminates are effectively removed. This desiccant mixture contains both molecular sieve and activated alumina. The molecular sieve is specially designed to provide maximum drying in today's systems. The activated alumina is ideal for capturing the large organic acids that the molecular sieve cannot.

HFC Refigerants and POE Lubricants - Part 1 : Why is it important?

The use of HFC refrigerants and Polyester [POE] lubricants for air-conditioning and refrigeration have generated new system chemistry related problems. New and redesigned system protectors have been developed to counteract these problems and provide a long, reliable life for the operating refrigeration system.

Moisture is the major problem causing contaminate for HFC/POE oil systems just as was for CFC and HCFC systems using Mineral oil. Many HFC's can hold much more water than their CFC counterparts but the oil differences are much worse than those of the refrigerant. POE oil can hold as much as 10 times more water than Mineral oils. In addition, evacuation has proven ineffective at removing this moisture so as a filter-drier is required to perform this function.

Water poses a new problem for POE oils above and beyond those experienced with Mineral oil. POE oil will react with water to form organic acids at normal operating conditions in refrigerating and air-conditioning systems. This reaction starts at water levels as low as 75ppm. These acids attack system components including motor insulation and metallic components --- reducing system life.

Advantages of EX Series Electrical Control Valves

The electrical control valves EX4, EX5, EX6, EX7 and EX8 from Emerson are optimized for control of liquid or gaseous mass flow in refrigeration systems. The stepper motor drive, which produces exact valve opening, is energized directly from the electrical power and therefore operates independently from differential pressure.



EX series electric control valves can operate from 2kW to 880kW (For R22).

Viewing lens / HMI moisture indicator

Moisture indicators on refrigeration equipment are critical early-warning components in the effort to lessen the long-term effects of water damage and reduce repair and maintenance costs. The proper moisture indicator must sense and report just how much water is in the system’s circulating refrigerant. An indicator in a viewing lens changes color as the moisture content reaches potentially damaging levels. Be sure to choose an indicator that is sensitive enough to alert operators early on that moisture levels are rising, allowing corrective action to be taken before serious system damage occurs. The Hermetic Moisture Indicators (HMIs) from Emerson are able to read moisture levels far below industry standards. The HMI actually begins to change color at two percent relative humidity (RH), which is a “very dry” indication. At 3% RH, the purple caution color begins to appear. Many other indicators do not begin changing colors until about seven to eight percent RH; however, early detection is critical with HFC refrigerants and POE lubricants. POE oil can hold up to 20 times more moisture than the mineral oil used by older refrigerants, which can allow corrosive acids to build up and totally destroy a system. The HMI is UL listed with a 680 psig maximum working pressure, making it acceptable for use with higher-pressure HFC refrigerants. It has a larger viewing window for easier visibility and charging. It is resistant to “washout” from water and can withstand brazing temperatures up to 450 degrees Fahrenheit [ 232 degree C]. The fully hermetic design includes a corrosion-resistant, all-brass body with no o-rings or knife seals that are likely to leak. The indicator features solid copper fittings for easy, universal replacement.



Lets look at the review from http://www.achrnews.com.

Simple guidelines for EK filter driers with refrigeration plants and air conditioning

Why use filter driers?
A refrigeration plant’s trouble-free life time is increased by:
– Moisture adsorption
– Dirt filtration
– Acid adsorption

When should I use filter driers?
As closed systems were once open and will be re-opened occasionally, filter driers will be of benefit in:
– Factory-made units
– Plants serviced or erected in the field

How and where should I use filter driers?
– Change the filter drier every time the system has been opened for service
– Mount/install a correctly sized filter drier in the liquid line after the receiver but before moisture indicators