What is a Multimeter?
Multimeters are also referred to as multitesters and VOMs. They are excellent tools that every electrician and HVAC technician must own. These devices are electronic tools or instruments that measure different parameters or units.
Some of the most popular parameters they are used in measuring include resistance, current, and voltage.
A multimeter comes in a compact, lightweight design that makes it easy to handle. This handheld device can either be a digital option or an analog instrument.
First, the digital multimeter comes with a display that shows the values of the parameters in digits. The models we reviewed in this article come in this form. They offer an LCD screen that is easy to read.
On the other hand, analog multimeters utilize a macro meter, and show readings view a needle on a dial. It is usually more difficult to read for the uninitiated.
Using and reading a multimeter
The ease of usage is largely dependent on your level of expertise and the model of multimeter that you have available.
At the base level, the two options that we reviewed work using similar principles. The unit often comes with a trio of ports and a red and black lead.
To get your readings, you will have to plug the black lead into your common port while the red lead can be put in either of the remaining ports.
One thing that you should note before you begin is to ensure that the circuit being tested doesn’t come with a higher voltage value than what your multimeter can handle.
Once the connectors are made, you can use your knob or dial to choose the multimeter mode. The modes are often pretty clear to see on the multimeter for you to choose from.
Reading your multimeter
Reading your unit can be easy or complicated. It is usually easy if you have previous experience using the tool and can be complicated if you are just starting out with using the device. However, with regular use and seriousness, you can be an expert reader.
First, you should note the values and units on the multimeter that you must understand.
One of such values is the “V”. This value is usually on the dial or knob, and it means voltage. For an analog unit, the V is often surrounded by different values. These show the voltage that you want to test.
On the other hand, if you want to test for current, you should look out for the “A”. A denotes amperes. Measuring it is quite straightforward. All you need to do is to look for the omega symbol on your device. Once this is active, you can start reading current values.
If you are just starting out, we highly recommend that you purchase a digital multimeter such as the Crenova MS8233D. Why? Well, digital models give you a definite value and are overall better to use.
An analog tester will also give you accurate values, but it is easy for these values to get lost in translation. You might have a hard time reading the values, especially if you are a beginner.
Overall, whether a beginner or a professional, we believe that you would appreciate the ease of use offered by a digital unit.
Differences between an HVAC Multimeter and regular multimeter
The HVAC multimeter in several ways is similar to a normal multimeter. However, there are certain differences.
The main difference between the two is that the ranges that you can read on an HVAC multimeter are much higher than what you would normally obtain on other types of multimeters.
Additionally, HVAC multimeters are far more durable than other types of multimeters. It comes with rubber gloves and parts that not only make it easier to handle, but also means that it can survive drops, bumps, and falls.
Another difference is the price. Considering the two factors that we considered above, it is not very surprising that the HVAC multimeter is more expensive than other options.
Let’s see some of these differences in more technical terms.
Differences in technical terms
- The HVAC has a higher voltage range. For that reason, you will find HVAC meters with the ability to read more than 500 Volts AC and up to 300 Volts DC. This is not usually obtainable in regular models. Additionally, they can read voltage as low as 1 Mv.
- In terms of amperage, an HVAC meter can read up to 300 A., and it can read as low as one-hundredth of an A.
- Your typical HVAC meter can read up to 5 mega ohms and as low as one-tenth of an Ohm.
- Lastly, it can read one-tenth of a micro Amp.
Aside from the features above, these units also come with several other features.
For instance, the screens of these units come with backlit displays. Therefore, you can use it in different conditions regardless of the light conditions.
The HVAC meter also comes designed with clamps. These clamps come in super-handy. They make it very easy to read loads. All you need to do is the clamp your clamp, well around the wire. This way, you will jettison the need for leads.
Another feature of these units is that they have LED lights and temperature probes.
As you can see, an HVAC multimeter is one of the best electrical measuring devices that you can get right now.
Benefits of HVAC Multimeter
Here are some of the main benefits of these units.
- They give automatic reading display
The HVAC multimeter comes with an automatic display that will make it so much easier to take readings. It relays the information into easily understood values on an LCD screen. While others might come with needles and such-like indicators, they are not usually easy to read except you are a professional. Furthermore, the display means that you can use it even in low-light conditions.
An HVAC multimeter offers you accurate readings, more than your other types of multimeters. Some of the units can give readings of up to three decimal places.
Since your HVAC system is usually connected to 220V lines, you need a unit that can handle such power. Thankfully, these models can handle high levels of power without issues.
Your HVAC multimeter can handle negative values without much hassle.
What to consider when buying a Multimeter
There are several factors that you should consider when buying your multimeter. Now let us see some of the most important information that can help you.
Type of multimeter
There are several types of multimeters on the market. Getting the best multimeter requires choosing the right type. Let’s see the types available.
This type of multimeter is, as the name implies, essential if you have an HVAC system. Your air conditioning unit and heating systems do not run on the regular lines. They are always installed on 220 v lines. Therefore, you must have the correct device that can handle the power from these electrical lines. Choosing the wrong multimeter will result in inaccurate readings and can even result in damage.
These models often come with a thermocouple probe. For example, the AstroAI Digital Multimeter, TRMS is an excellent device that can handle plenty of power without damage, expect you plug it in the wrong way.
Aside from damage to the device, using the wrong unit on a 220-V line can even result in electrocution.
- Automatic ranging multimeter
This is another type of multimeter. As the name implies, this type of multimeter automatically sets the range.
In normal circumstances, you would have to connect the meter to the resistor and manually begin to search until you get the range that you want.
Well, with this unit, that problem disappears. Instead of manually searching, it does all that for you. Therefore, it is very easy to use and super-handy. An example of this type of multimeter is the INNOVA 3320.
- Manual ranging multimeter
This unit can be said to be the opposite of the automatic ranging multimeter. In this case, you will connect the multimeter to the resistor and manually search for the range. It offers you a greater level of control than usual. Therefore, professionals find it very handy. One example of this type of multimeter is the Etekcity Digital Multimeter MSR-R500.
The Fluke models are units that are designed to withstand adverse conditions without breaking down. They are made from high quality and durable materials that ensure their consistent durability.
With these units, you can check batteries as well as carry out a wide variety of other tasks. They are often immune to weather and hazardous conditions.
One way that they are used in dangerous circumstances. You can place this type of multimeter at a distance and take readings to your phone or other devices.
This is the anti-thesis to the digital multimeter. It comes with a needle or pointer that shows the value of your unit under consideration. They are very versatile and can measure various parameters from resistance to voltage and duty cycle.
As the name implies, this model comes with a digital display. The display, usually, LCD, shows you the values of your measurement.
They are the simplest types to read on the market today.
Range Limit
One of the most important parameters to consider when choosing an HVAC multimeter is the range limit. Since you have not carried out any measurements, you might have no idea about the parameters your project will demand. That is why it is important to get a model with plenty of range. In other words, your HVAC multimeter should be able to handle your current and future tasks.
There are certain recommended ranges.
If you are testing for current, we recommend from 10uA to up to 10A.
Since resistance is another important parameter, we also recommend that you get a model that offers a range from 10 ohms to up to 20 mega-ohms.
If you are checking for voltage, then your model should be able to handle between some millivolts to up to 650 Volts. The KAIWEETS Digital Clamp Meter T-RMS offers up to 600 volts which we found to be quite satisfactory for most tasks.
Input Resistance
If you are not a professional, you might find this to be a strange parameter. However, it is one of the most important features to consider when choosing a multimeter. The input resistance refers to the resistance that builds in the multimeter, when it connects across the probes of your device.
As a rule of thumb, the higher the value of the IR, the better the HVAC multimeter. While you cannot go around checking for the value of each model on the market, you should consider a value of 1 mega-ohm to be a good indicator that you have a quality model.
Accuracy
Since you are meticulous about your work, you will likely want the most accurate reflection of the parameters. While some might not consider it to be very important, any electrician worth their salt knows that accuracy is vital.
To determine the accuracy, the number of counts is handy. If your device falls between 4000 to 6000 counts, then it will give you accurate results. The Fluke 116/323 KIT HVAC Multimeter is one of the most accurate on our roundup. It gives you up to 6000 counts.
True RMS
If your device offers you true RMS readings, then you can carry out any large HVAC project. This feature ensures that you can measure different stuff, including the distorted waves that affect accuracy. The AstroAI Digital Multimeter, TRMS is one of the models on our roundup that offers correct RMS readings.
Price
As with many other products on the market, HVAC multimeters come in a wide range of prices. Some cost a few dollars, while others are heavily priced.
When choosing a model, price shouldn’t be a heavy indicator of value. After all, some low cost options offer even more benefits to you than more expensive models. Our budget pick, for example, the Etekcity Digital Multimeter MSR-R500, comes with several really impressive features.
Ease of Use
If you are just starting out, you do not want to jump into the deep end, as it were. Rather you should test out the waters using a simple, entry-level HVAC multimeter. Choose a model that comes with clear instructions and parameters.
Brand
There are obviously many brands on the market. Most of the units we have chosen above come from some of the best brands today. Since not all brands offer reliable products, we recommend that you opt for a brand with a track record of reliable devices. Some of the best include Fluke, Fieldpiece, Crenova, etc. Buying your HVAC multimeter from these is a guarantee of quality.
