Measure System Capacity and Efficiency

System tune-up time is here. Imagine if you could give your customers a report that shows the system capacity and efficiency before and after your system tune-up! There is a tool that can do that, the iManifold. It not only can measure system characteristics such as pressure, temperature, superheat, and subcooling; it can use the measurements to determine BTUs/hr capacity and system EER. To be sure, you need a few other measurements; namely, dry bulb and wet bulb in and out of the evaporator as well as system operating voltage and current. The iManifold with the correct accessories can measure the characteristics necessary to do system capacity and efficiency calculations and perform the calculations. It can also produce reports showing the details, including system capacity and efficiency. The report can be printed or e-mailed to the customer. The only “report” most customers get now after a traditional system tune-up is a bill. The iManifold and iConnect are the only tools I know of that can do this.

What accessories do you need? You also need two wireless temperature/humidity probes made to work with the iManifold and an electric meter that can communicate with the iManifold. The iManifold and the necessary accessories required to measure system capacity and efficiency are definitely more expensive than many other digital gauges. However, the iManifold does things other digital gauges cannot do.

To learn more about the iManifold chaeck out their web site imanifold.com

Digital Data Recording and Reporting

A relatively new class of communicating digital tools makes it possible to share your readings electronically. They not only take accurate pressure and temperature readings, they can share those in an email with your supervisor, company, customer or energy utility. And many of these can take more than just refrigerant pressure and temperature readings. The Stride I-Manifold, Testo Smart Probes, Fieldpiece System Analyzer, Sporlan Smart Tools, Yellow Jacket Mantooth, and Appion ION gauges can all send data to your electronic devices, which then use free applications to create and send the reports. Some can collect information from a variety of instruments and report on them as well. For example, you can also get ambient temperature, indoor wet bulb, and indoor airflow. I am sure I probably missed a few.  The point is, tools are available now that can do more than collect data; they can help you organize it and report your results.

The reporting capability allows you to document what you have done. For example, you can produce before and after reports showing the system performance when you arrived and the system performance after you have made adjustments. You can also send reports to your supervisors if you need help. Some utilities have rebate programs which require that the contractor use a particular reporting setup. The idea is that the utility can verify that the system really is performing as designed by the manufacturer.

This is both exciting and a little bit intimidating. Until now, if you went on a call and checked the system performance, you were generally the only person that would see all the measurements and make the judgement. If you have checked more than a handful of systems, you know that checking system performance really is a judgement based on a lot of variables. And, you only have control of a few of those variables. It is not as simple as matching a couple of pressures and temperatures.

There is the outdoor temperature, the indoor temperature, the indoor wet bulb, the airflow across each coil; any one of which can make your system perform in a way you don’t expect. That is before issues such as plugged expansion valves, restricted filter driers, underperforming compressors, or installation errors. All of these things must be verified before adjusting the charge. It would be nice if we could just state a couple of pressures and/or temperatures and leave it at that, but that is not reality. Even manufacturer performance charts and tables assume a lot of this information. If just one value is off from the assumption, the manufacturer’s chart will not work.

So, if you ever needed any incentive to up your game when checking systems, having to send reports to supervisors, utilities, and customers should do the trick. Beer-can cold is just not good enough in an environment that expects documentation and verification. That is unless you plan to strap a can of Coors to the suction line and send in a photo of the color change. Here are a few links to check out these new-age tools.

Appion - http://www.appioninc.com/products/ptgauges.html
Fieldpiece - http://www.fieldpiece.com/products/detail/sman460-wireless-4-port-digital-manifold-with-micron-gauge/system-analyzers/
I-Manifold - http://imanifold.com/
Sporlan - https://sporlanonline.com/smart/
Testo - http://www.testo.us/smartprobes/index.jsp
Yellow Jacket - http://yellowjacket.com/product/mantooth-dual-pressure-wireless-digital-pt-gauge/

Affordable Wireless Probes

I just got my first opportunity to play with my new Testo smart probes. The 549i measures pressure and the 515i measures temperature. They are wireless Bluetooth devices which rely on an app that you load on your smart phone or tablet. They are part of a complete lineup of wireless Bluetooth devices that Testo is introducing. I was interested in them because of the low price point. The 549i and 515i are each around $50.  To read both system pressures, the suction line temperature, and the liquid line temperature simultaneously costs around $200.

The App

The Testo Smart Probes app interfaces with all of the smart probes. My first impression is generally positive. Like Testo’s Digital Manifold Gauges, the software does have a small learning curve. However, once you get past the initial setup and learning where all the settings are, you can easily check system pressures, superheat, and subcooling simultaneously. You can choose from a menu of applications which range from a basic list of each probe’s output to a software application designed to make a particular job easier. The software will also do data logging. Each application allows viewing the information as a list, trending (a graph), or a table. With the graph or table view, every time the probe updates its reading, that new reading is plotted on the graph or added to the table. You can export these to pdf, excel or jpg.

Accuracy

The accuracy is reasonable. For improved accuracy, the 115i temperature probe uses an NTC sensor rather than a thermocouple. The specification is plus or minus 1.3° C ( 2.3° F). Its resolution is 0.1, meaning it can display tenths of a degree.  Its range is -40°C to 150°C ( -40°F to 302°F). The 549i pressure probe has an accuracy of plus or minus 0.3 bar (4 psi). The resolution is 0.1, meaning it can display tenths of a pound.  The range is -1 to 60 bar (-14 to 870 psi).

In the Shop

The software and Bluetooth worked well with both my i-phone and my Android tablet. The range seemed fine, I connected to the system and walked around the shop. The app did drop some of the probes occasionally, but they always reappeared in a few seconds. This happened even if I was right next to the probes – so I don’t think it had to do with the Bluetooth range. There is also a latency in the readings of a few seconds. When I disconnected the pressure probes the pressure still showed on the screen for a few seconds.

Batteries

What remains to be seen is how long the batteries last. Each probe uses 3 AAA batteries. It could get a little expensive if I have to replace batteries a bunch. Also, I know neither my phone nor tablet will go all day, so to use these in the field a lot I would need to figure out a convenient way to recharge them.

Wrap up

The exciting part is that these probes bring the wireless world to you at a very affordable price. Just a good quality thermocouple pipe clamp that plugs into your multimeter costs $50. The 115i gives you more functionality and convenience for about the same price. The 549i lets you check system pressures without filling a manifold or hoses up with refrigerant. And both allow you to export the data, so you can provide your company and customers with verification of the system’s performance. Here is  link to a web page about the Testo Smart Probes. https://www.testo.com/en/home/products/smart_probes/smart_probes_heating_1.jsp

Bluetooth Tools for HVAC

At the recent HVAC Excellence Instructor’s Conference there were many digital tools featuring Bluetooth connectivity on display. These tools allow you to use phone and tablet apps which take readings from the device as input. This can be as simple as just displaying a reading, or more helpful such as using the reading to perform a calculation. Most also allow the user to use their phone or tablet to send the information to someone else. Technicians can send real time readings to a service manager for consultations or document results to verify system operation. Most of the devices were measuring pressure and temperature. Of course, the Stride i-manifold was there. It was actually introduced last year. This year they have company. Fieldpiece has had wireless gauges longer than anyone else, but they used a proprietary signal. This year Fieldpiece was showing a set of digital gauges with Bluetooth and a Bluetooth wireless bridge to allow their older Fieldpiece wireless gauges to connect to Bluetooth.

 Yellow Jacket, Appion, and Sporlan all had pressure and temperature measurement tools which featured Bluetooth connectivity and apps designed to work with the tools. To be sure these are not manifolds, but pressure and temperature measurement tools. Appion had a trio of pressure gauges and a Vacuum gauge. Their gauges each have a digital display as well as sending Bluetooth information to your phone. They are “short” gauges with a short stem, allowing connection without filling a set of hoses with refrigerant. The Yellow Jacket Mantooth device is also a “short” gauge, but it has no display. Like the i-manifold, it relies on your phone or tablet for a display. The Mantooth consists of a digital pressure gauge with a tethered temperature clamp. Sporlan was showing off a set of digital pressure and temperature devices with Bluetooth connectivity. They also rely on the connected device for a display. 

All Bluetooth devices were not gauges - Fluke and UEI were showing Bluetooth enabled digital multi-meters and clamp amp meters. 

All these devices were showing apps designed to work with the device and extend its usefulness. Most can be freely downloaded. The i-manifold app is a killer app that is useful even if you don’t have an i-manifold. The Stride folks are hoping you will get tired of typing in the pressures and temperatures and pick up an i-manifold. One final consideration – If your gauges, multi-meter, thermometers, and vacuum gauge are all connecting to your phone while you work, you are going to need some extra juice to keep operating. You will need an extra battery pack or two for your phone, most phones won’t operate all day long without a recharge.  

Playing with Your Phone on the Job

Many companies now issue company cell phones to their service techs. The phones are intended for communication, so the company can find the techs and talk with them virtually anywhere, anytime. Now those phones may need to be considered part of the technician’s toolbox. There are already many great apps, including free pressure-temperature apps – usually from refrigerant companies. Equipment and parts manufacturers have started producing apps for looking up parts and equipment service specs. Now you can use your phone or tablet to read the system pressures, line temperatures, superheat, and subcooling. Stride Tools (Imperial) released the i-manifold last year. It is a four port manifold without a display. It sends the information wirelessly to your phone or tablet, and your device becomes the display. Since the display is literally on a small computer, the app can do all kinds of cool things. For one, they have wireless thermometers that can work with the i-manifold to determine system operating conditions, capacity superheat, and subcooling. But wait – there’s more! Now Yellow Jacket has come out with a small device they call the mantooth. It connects to the system and has a tethered temperature probe. It also has no display, but sends the information to your smart device via Bluetooth. So you can see system pressures, temperature, superheat, and subcooling all on your phone. The advantage of this device is that you don’t have to fill up a hose with refrigerant to get a reading – so refrigerant loss is minimal. The “short” gauge concept is perfect for simply testing system performance. Another well known manufacturer is also testing “short” gauges that connect to smart phones and tablets. Their devices are also “short” gauges – eliminating the refrigerant loss from connecting hoses. Their gauges do have their own display as well as connecting to your device through Bluetooth. They are developing wireless thermometers to work with these gauges. Again, you will be able to see all relevant system operating conditions on your smart device and you won’t have to lose several ounces of refrigerant just to perform a check-up. You may soon be playing with your phone on the job – to improve your productivity!

Digital Gauge Roundup

Just a few years ago there were only a few choices if you were looking for a gauge manifold with true digital gauges. Now there are at least 16 different options available. There are also at least two new options that are very different from the others. The most expensive have a retail price in the $1,000 range, but there are at least four offerings in the $300 range. Nearly all of these are billed as Digital System Analyzers because they do more than measure pressure. All of them also measure temperature, many also measure vacuum, and all will perform calculations such as superheat and subcooling. Even though they are still a bit expensive, by the time you compare them to the cost of a set of gauges, thermocouple thermometer, and vacuum gauge they start to look a lot more affordable. If you don’t currently own a vacuum gauge and digital thermometer (not an infrared thermometer) you can consider the cost of a digital system analyzer as part of the cost of acquiring tools your are SUPPOSED TO HAVE! A vacuum gauge will cost around $200 and a thermocouple thermometer and clamp $150. When you add that $350 to around $100 for the least expensive analog gauge set that is good enough to use, you are looking at $450.

The least expensive analyzers have a standard 2 valve manifold and no vacuum gauge while the more expensive models typically have a better 4-valve manifold and a vacuum gauge. At least two models feature wireless data connectivity as well. Be aware that the prices you see usually do not include hoses. A good set of hoses can cost $100 if you are getting three 1/4” charging hoses and one 3/8” vacuum hose. If you are getting large hoses, such as Appion 3/8” or 1/2” hoses, they can cost $100 a hose. So when shopping, make sure you are getting an analyzer, a manifold, and hoses - unless of course you are going to use one or more of those pieces you already own.

The gauges that read vacuum typically switch from displaying pressure to displaying microns of vacuum at some point during the evacuation. On the subject of vacuum, one problem with having a vacuum gauge built into the gauges is that the gauges are not the best place to be checking the system vacuum. However, I have used a Fieldpiece set like this and have been generally pleased with the result. So far, our Fieldpiece SMAN4 set has held up well under student use. Yellow Jacket has a built in vacuum gauge in theirs, but a separate vacuum sensor so you can still measure the vacuum at the unit but use the built in vacuum gauge in the analyzer.

Hilmor has a digital gauge set that has both analog like displays and a digital readout. It looks a bit more like a traditional gauge set but still gives you all the digital goodies. I find the Hilmor gauges the easiest to use – no screens to scroll through and all the information on display all the time. Imperial has a brand new i-manifold which has no display! It uses Bluetooth to connect with your smart phone or tablet and uses that as the display. With the display being part of an app, it can do a lot more things and be more easily updated. You can download the app for free and use it by entering the temperatures and pressures. Pretty shrewd move! Once you get hooked on the app you will want the manifold to go with it, like the story “If You Give a Mouse a Cookie.” If you are not conversant with that reference to classic literature, you probably don’t have kids. Finally, my friends at Appion are coming out with digital high side, compound, and vacuum gauges that connect to the side port of the valve core tool they sell. No manifold needed!

I have uploaded a table of available digital system analyzers with a summary of the features of each. The file, “Digital_Gauges,” is in the Survival Kit on my Google Drive. I gleaned these from information available on the internet. The Appion gauges are not included because they are not released yet, but I saw them in March at the instructor’s conference in Baltimore. The address for the survival kit is https://drive.google.com/#folders/0B0i1Mw3czgHrLTN4M1p1LVh6Yms

Understanding Pressure Gauge Specifications.

Pressure gauges have many specifications which technicians should understand when selecting a gauge, including range, resolution, accuracy, proof pressure, and burst pressure.

The range is the lowest to highest reading on the gauge. It is important that the range of a gauge fit the pressures for which it will be used. You want a gauge able to read the highest pressure you might encounter, but you don’t want the top reading much higher than that. This is because accuracy is stated as a percentage of full scale. A gauge with an accuracy of 1% and a top reading of 300 psig has a possible error of 3 psi. If you make the top reading 600 psig, now the possible error becomes 6 psi. If the pressures you will be reading only go up to 250 psig, expanding the top pressure reading just makes the error larger.

Resolution is the smallest indication the gauge can display. A gauge that can display in tenths of a pound has a resolution of 0.1 psi. This is not the same as the accuracy. Just because a gauge CAN display in tenths of a pound does not mean the reading is accurate to tenths of a pound. However, having a small resolution does make the gauge more useful for precise readings than another gauge with the same accuracy and top scale. For example, there are both analog and digital gauges with the same accuracy, but an analog gauge with a scale of 0 – 500 psig cannot have a resolution in tenths of a pound – there is just not enough space. A digital gauge with the same accuracy and top reading has no problem displaying in tenths of a pound.

Accuracy is stated as plus or minus a percentage of full scale. Full scale is the highest reading on the gauge. To determine how far off a gauge can be and still be within specifications, multiply the percentage accuracy times the top reading. For example, a gauge with 1% accuracy and a top reading of 500 psig would have an accuracy of plus or minus 5 psi. Note that the accuracy is plus or minus a percentage of full scale, NOT, a percentage of the reading. For example, a reading of 400 psig could indicate a pressure anywhere from 395 psig to 405 psig. This is not too bad at 400 psig, where 5 psi only represents 1.25% of the actual reading. However, plus or minus 5 psi becomes a problem at lower readings. A reading of 25 psig could indicate a pressure anywhere from 20 psig to 30 psig.  Now 5 psi represents 20% of the actual reading. For accuracy reasons, you don’t want the top reading on a gauge to be any higher than it has to be to get the job done.

Temperature compensation is an important aspect of accuracy in digital gauges. The accuracy of the sensors used in digital gauges changes with temperature. A gauge that specifies an accuracy at a single temperature is only that accurate at that temperature. It will be less accurate at other temperatures. A temperature compensated gauge maintains its accuracy over a wider range of temperatures. The most accurate digital gauges will be temperature compensated.

Proof pressure is the highest pressure the gauge can withstand without damaging the sensor. This is typically considerably higher than the highest reading.

Burst pressure is the pressure at which something on the gauge physically breaks. It is higher than the proof pressure. Gauges should be selected with proof pressures and burst pressures considerably higher than the highest pressure you would expect to encounter. A gauge which would be perfectly acceptable for use with systems using R-134a might not be acceptable for use on systems using R-410a.