Author: clidzbarski@fieldpiece.com

Temperature is everything

The key to understanding HVAC system performance is… to take its temperature! The supply and return temperatures, or Delta T, offer a technician crucial details about heat transfer at the evaporator coil, performance of the heat exchanger, refrigerant charge, and the effectiveness of air flow within the conditioned space.

Know exactly where to take the temp

Assessing system performance starts with measuring the supply side and return side temperatures. First, locate the supply air duct close to the air handler or the furnace. This is an optimal place to measure. If necessary, drill an access hole a few feet downstream of the heat exchanger or the evaporator coil for accurate readings.

To measure the return air temperature, measure in the duct closest to the furnace, drilling an access hole in the ductwork, if necessary. This measures the air returning to the HVAC system from the conditioned spaces. Ensure consistency by measuring at the same location each time.

Best practices for accurately finding temperatures

When taking readings, always stabilize the system first by running it for 15-20 minutes. Then, ensure the temperature probe is not affected by drafts or nearby heat sources such as heat strips found in heat pumps. When inserting the probe through an access hole, be sure that it’s placed in the airflow, and not touching the duct walls. Once finished, seal the access point to avoid air leaks.

Make sure the probe is inserted in the duct and not influenced by the room air. Consider taking readings at multiple supply vents to check for uniformity as well. If there are large discrepancies in readings at different locations, the system could have ductwork or airflow issues.

Benefits of Measuring Out of Duct

Delta T is most accurately measured in the duct, but prior to drilling, technicians can get a quick estimate by measuring temperatures at the nearest return vent and supply register or grill. Additionally, taking measurements at the end of the return and supply can assist a technician in diagnosing temperature loss or gain due to duct leaks.

Tools designed for the job

Fieldpiece makes many wireless, handheld tools designed specifically for quick temp checks. When measuring temperature in a duct, or at a register or grill, here are a few of our favorites:

• PRH2 Digital Psychrometer – Use this versatile, pocket-sized psychrometer to measure wet bulb, %RH, dew point and dry bulb temperatures. Readings are shown on the backlit, dual display and the tool can measure temps in the duct or while walking around.

• SPK1 Pocket Knife-Style Thermometer –This digital thermometer opens just like a pocketknife and features a sharp tip for piercing through flex ducts. It hangs easily at any angle from a vent or thermostat.

• SPK2 Folding Pocket In-Duct Thermometer – Also great for taking quick air temperatures, this folding thermometer rod can punch through flex ducts and easily hangs from a duct or on a grille. Not in the mood for math? The SPK2 holds measurements and calculates the delta T for you.

• SPK3 Rod and IR Temperature Pocket-Style Tool – In addition to a duct-piercing thermometer rod and delta T calculator, the SPK3 includes an IR feature with an 8:1 field of view angle and laser guide. The perfect tool to use when you’re doing a walk-around check of air temps at registers in hard-to-reach locations.

• SIG1 Gun-Style IR Thermometer – This standalone, non-contact infrared thermometer features a 10:1 field of view, a bright blue backlight, and a laser guide for fast, accurate readings.

Thank you for coming to our Temp Talk

As an HVAC pro, listen to your system’s air temps – they’ll tell you a lot about system performance. If you want to measure these temperatures quickly and precisely every time, pick up some of these powerful pocket tools from Fieldpiece.

A vacuum pump is a powerhouse machine that removes air, gases, moisture, and contaminants from a system to create a clean environment for refrigerant. These efficient and powerful machines need clean oil to perform at their peak. When oil becomes cloudy or saturated, the pump won’t work as well, and pulling a deep vacuum takes longer.

Double-duty Oil

The oil in the vacuum pump acts as both a lubricant and as a sealant. It keeps the pump vanes (rotor blades) lubricated and helps keep a proper seal for an optimal vacuum. The deep vacuum that the pump creates helps push moisture and non-condensables from the system to the pump, ensuring the system is ready for refrigerant. This process contaminates the oil in your vacuum pump, which negatively impacts the pump’s performance and efficiency by compromising its internal seal. Pumps with contaminated oil will struggle to create a strong pressure differential, leading to increased evacuation time and eventual damage to the pump.

When to Change the Oil

The need to change your oil will depend on several factors. The most effective way to maximize performance and efficiency of your vacuum pump is to change the oil after each evacuation. In humid environments systems are more likely to contain moisture. Systems with more moisture and non-condensable contaminants present will contaminate your oil faster, requiring more frequent changes to maintain performance. Moisture contamination is easy to spot because the oil looks milky or cloudy. Other contaminants can sink to the bottom of your oil reservoir, so vacuum pumps with better reservoir visibility, such as the large window on the Fieldpiece vacuum pumps, allow for more accurate monitoring.

Another key indicator that it’s time for an oil change is pump efficiency. When pulling a vacuum, if the rate at which your microns are decreasing starts to level out, this could signal the need to change oil. When pump efficiency starts to wane, pulling a deep vacuum becomes more time-consuming. Note that the time to pull a vacuum will vary depending on the size of the system, atmospheric conditions such as humidity, and the efficiency of your evacuation setup.

Oil Changes on the Fly

Some pumps on the market allow the oil in the pump to be changed while it’s pulling a vacuum, like the RunQuick® oil change system on Fieldpiece vacuum pumps. Towards the end of the evacuation is when you need fresh oil the most, so oil changes on the fly are key to working faster and smarter.

Get a Vacuum Pump that Works for You

Since clean, dry oil is crucial for faster evacuations, consider vacuum pumps that make oil changes quick and hassle-free. Fieldpiece vacuum pumps are powerful, portable and offer oil changes on the fly, saving you time on every evacuation. See the entire line of pumps, oil and other HVAC tools built and designed for techs.

For refrigerant heating and cooling systems to work correctly and optimally, the refrigerant must be free of air, nitrogen, moisture, and contaminants. Therefore, before charging a system, it’s critical to evacuate the system with a vacuum pump to create a clean and sealed environment. Here are a few tips and best practices to make your next evacuation faster and more effective. 

Tip 1: Purge with Nitrogen 

Moisture in a system can drastically increase the time it takes to pull a vacuum and removing that moisture and other contaminants is a crucial step to saving time. To ensure that the system is free of excess oxygen, refrigerant, moisture, and other contaminants, purge it with nitrogen. This is different than flowing nitrogen or conducting a nitrogen pressure test. To purge, connect a nitrogen tank and flow nitrogen through the system at around 100 PSI. This allows nitrogen to flow into one side and then out the other. The movement displaces excess oxygen and air. It also removes any dangerous gases and ensures the system is dry. While performing this purge, be sure to keep the area well-ventilated. Nitrogen can displace oxygen and create a dangerous environment for techs or other occupants, so always keep this in mind. 

Tip 2: Triple Evacuate 

When working in humid environments or on systems with significantly more moisture, a triple evacuation is a great way to remove the moisture entirely. This is an industry requirement for some OEMs, and one of the most effective techniques for systems with high moisture content. Start by sealing the system off and pulling the system down to a vacuum of between 1000 and 2000 microns. Then, break the vacuum by introducing nitrogen for 5 minutes at 5 PSIG. Perform another evacuation to 500 microns, and then break it again with nitrogen for five minutes. Perform a third evacuation and pull the system down to between 200 and 300 microns. Let the system sit for 10 minutes, or longer for larger systems. Performing the triple evacuation purges with nitrogen helps the excess moisture and other contaminants vent out of the system. Not to mention, systems with less moisture allow for pulling a vacuum faster, saving you time on the job. 

Tip 3: Change Your Oil 

Within a system is not the only place where moisture can impede evacuation efficiency. High moisture content in your vacuum pump oil considerably reduces your pump’s ability to pull a deep vacuum quickly. Cloudy oil is a sign of moisture buildup, a natural occurrence in used oil. Vacuum pumps with clean, dry oil can maintain a higher pressure differential, speeding up the vacuum process and allowing for a deeper vacuum. This means more frequent oil changes directly improve your ability to evacuate systems quickly, once again saving you time on the job. With Fieldpiece vacuum pumps featuring the RunQuick® oil change system, you can change oil in seconds without losing vacuum.  

Effective tools are only part of an effective service. Staying informed and up to date on best practice is just as important, so we hope these tips help make your system evacuations easier, faster, and better! 

During peak cooling season, removing a valve core on the job is as common and necessary as finding shade. Removing the core opens the valve completely, eliminating flow restrictions for faster recovery, evacuation, and charging. To simplify your job, Fieldpiece has a lineup of three valve core removal tools (VCRTs) that eliminates the trial-and-error process (and frustration) often faced with other tools.

Locked In
With a press-fit gasket design, the tip of the capture rod locks in the valve core the first time, every time. No adjustments necessary. With the valve core reliably secured, it won’t fall off within the tool or get lost once it’s removed. All models of Fieldpiece VCRTs have a magnetic cap on the capture rod to safely store the locked-in core on the system housing, keeping it clean and handy. PRO TIP: best practice is to always replace the removed valve core with a new one.

Seeing is Believing
Almost every technician has played the “Did I Get It?” game when removing the valve core. With no way to confirm that the core has been successfully captured before removal, you are left to remove the rod and check, releasing some refrigerant with each attempt. Also, if the core has fallen off within the tool, a quick (and dangerous) opening of the valve on a charged system can eject the core at high speed. Did we mention the frustration that sets in after multiple failed attempts to remove the core? To eliminate this annoyance, the Fieldpiece VCG1 and VCG2 feature an integrated sight glass. You can clearly see the end of the rod through the sight glass and confirm the valve core is attached before extracting it – sanity intact. The sight glass can also be used to verify that refrigerant is flowing.

Two’s Company
The VCG2 model also includes a second ball valve on the side port. This convenient addition allows you to easily isolate and protect a connected vacuum gauge from refrigerant contamination. Since the second ball valve is integrated into the VCRT, you no longer need to add a fitting to gain an isolation valve, which increases bulk and introduces a new potential leak point.

Made to Fit your System
All three Fieldpiece VCRTs come standard with a 1/4” service port fitting that may be swapped with an optional 5/16” fitting on the jobsite. You no longer need to purchase and haul additional VCRTs to accommodate different system ports, simply keep the swappable fitting in your toolkit. Fieldpiece VCRTs are the right tool, every time.

Thumbs up!
Inserting a core when a system is pressurized can be awkward, except when you have a comfort spinner! The VC1G and VC2G tools feature a rubber-coated, free-spinning cap that lets you use your thumb to hold the capture rod in place, against pressure and easily thread the core with your other hand. Another tech-friendly feature from Fieldpiece.

It’s a Fieldpiece
The VCRT lineup is another addition to our arsenal of rugged tools designed to make life easier for technicians everywhere. We stay committed to innovating in the HVACR industry and providing tools and instruments that survive the test of time while making jobs easier, faster and better.