Vacuum pump for HVAC – how does it work?
Before we make a purchase, we need to understand what a vacuum pump is, what it does and whether or not it is the right piece of kit for what we need. You might have noticed when looking at the products we’ve reviewed that there are many different options and that some can even be used as pumps in different household and mechanical scenarios.
Basically, an AC vacuum pump is something that can “suck out” the unwanted air and any water vapor in the system, ready for it to be serviced. When the AC unit needs to be repaired, the first step involves removing this vapor and recovering the refrigerant from the system to use later.
You will have to take other steps such as ensuring that the whole system doesn’t have any leaks. This is made easy by some of the vacuum pumps on our list which actually include leak detectors so that you can do this part of the job.
The evacuation is the most important step, getting everything out of the refrigerant system ready to charge it and test the system without any vapors getting in the way.
Features to consider when buying a vacuum pump for HVAC
The following are the key features to think about when you are buying a vacuum pump for HVAC. We’re trying to make it as simple as possible, even for people who have never used a pump before, or serviced a HVAC, but are looking to do so for the first time. What do these
Materials
What materials are used to make the vacuum pump? Is it a high-quality pump and is the workmanship clear to see when you use it. A lot of these pumps choose to use aluminum for the casing. Aluminum does a very good job of being relatively sturdy, but also managing not to be too heavy. This means that it is a favorable material. On top of this, it is also good for allowing the heat to dissipate pretty quickly.
It is normally the case that the cheaper you are willing to go when making your purchase, the lower the quality of the materials will be. However, if you only use your vacuum pump occasionally then this might not be too much of an issue. The Fieldpiece Vp85 is a good example of a vacuum pump with plenty of quality materials used in the construction.
CFM
The CFM refers to how quickly the pump can clear the system and create a vacuum. CFM stands for cubic feet per minute, and though the maths to work it out precisely is complicated, it is simplified so that you can simply measure the numbers against one another. Higher CFMs means it will clear out larger systems a lot more quickly.
For a home system, anything between 3 and 6 CFM should be fine, but you might want to go a bit higher if you are using it in a commercial setting. All of the pumps on the list will eventually clear out the system eventually, but a higher CFM just makes things a lot quicker.
Vacuum level
This is another complicated measurement that can be simplified to allow you to compare one model from another.
When creating a vacuum within the system, you will be looking for a low rating for the vacuum level. Microns are used to measure this. So if you did want a perfect, flawless vacuum then you would need zero microns within the system.
This isn’t realistic, nor is it required. Micron levels of 500 and better are fine for most home use products.
The Robinair (15500) has a micron level of just 35, and produces some very professional results.
Stages
This is another piece of terminology to get to grips with when you are trying to understand how HVAC pumps work.
A single-stage model is either on or off, whereas a two-stage model can operate at different levels. The stages can relate to the maintenance costs, and single-stage models tend to be more basic in their design.
The Robinair (15500) is one of the most affordable ways that you can get a two-stage model of vacuum pump for a HVAC. It’s great if you can get two stages but if not then it isn’t too much of a big deal.
Oil capacity
Vacuum pumps will require some oil inside the system in order to run, and this measurement of how much oil can be kept within is really simple. More oil often means less frequently needing to change it, of course.
A lot of the models out there feature windows. For example, with the ZENY, you can constantly see how much oil is remaining and the quality of the oil, so when it might need to be changed.
10-12 Oz is a pretty standard. The VIVOHOME, for example, has just under 12 Oz capacity.
Warranty
As with all sorts of different products around the home, it makes sense to find a model with the longest warranty you can possibly get. For some full HVAC systems it is not unusual to find really long warranties of five, seven or ten years. For the accessory products such as the vacuum pumps, it is a lot less likely you will find this length of warranty. Instead, a vacuum pump for your HVAC system will probably have a one year warranty if you are lucky. We named the FJC 6912 as the best vacuum pump for a long warranty.
Most of the vacuum pumps we’ve mentioned and reviewed do come with a one year warranty so you have at least some protection when you make your purchase.
Dimensions and weight
The dimensions and the weight of the pump aren’t the number one priority, but there is really no need to have a huge, heavy product unless you are looking for a commercial-grade, professional vacuum pump. A lot of the products on the list weigh around 10 lbs, but if you want to go for a bit more rugged quality and a USA design, you might want an option like the Fieldpiece Vp85 with a 28 lbs design. This isn’t ideal for everyone and storing it within your home would not be the easiest thing to do.
Easy installation
Your vacuum pump shouldn’t be difficult to install and get set up ready to take the air out of the system and create a full vacuum. It is ideal if it is easy to set up, and for beginners, and people who are not HVAC professionals this can be pretty tough. Some of the models that come as sets feature color coded hoses and other simple examples of ways the installation can be made easier. The VIVOHOME has been named as the best set, and there is good reason for this, the easy installation is made simpler by having everything you need ready to go within the package if you buy this vacuum pump.
Safety
What sort of safety features should you be on the lookout for when you are trying to find a vacuum pump for HVAC. If you haven’t used these sorts of pumps before and you aren’t used to performing your own maintenance then it is even more important you don’t give any sort of a hazard by buying the wrong pump.
A lot of the safety features relate to overheating. Historically, some vacuum pumps that were not very well-made could cause an overheating risk, this could mean that it broke, or even worse, it could cause a hazard around the home or cause a fire risk. Many of the models have incorporated cooling systems to prevent this from happening, including our overall editor’s choice, the XtremepowerUS, a fantastic model for a variety of reasons but not least of all the safety that comes inbuilt.
Durability
Obviously, durability is a big deal with these sorts of products. You don’t want something that will simply break after one or two uses. The materials used play a huge part in this. A good example of safety features includes the Robinair (15500) which has anti-slip feet, meaning that the pump stays safely in the same place throughout the usage.
Ease of use
How easy is the product to use? It is worth considering how quickly and easily it can start to remove the vapor and other unwanted materials from the HVAC system before performing maintenance.
The best vacuum pumps come with clear instructions to help you to work out exactly how they are controlled.
Of course, it is definitely worth mentioning that all of these products do require a level of knowledge and expertise, anyone who is not quite sure what they are doing should avoid taking any risks by starting to perform maintenance on their HVAC system without being fully aware of the risks involved and what they are doing. You can always call a professional in for help if you need to.
Extra features
A lot of the extra features included come in the form of safety features such as the safety feet to keep a product in place, or the huge amount of accessories some of the vacuum pumps come with. The VIVOHOME is a great example of this. While it is not quite the best model on the list in terms of durability and build-quality, it has a lot of extra features and accessories including 1 bottle of oil, 1 leak detector, carry bag and gauge set included.
