Hi I’m Wes Davis, Technical Services director with ACCA. Today we're going to go over the ANSI ACCA Resnet ICC Standard 310. Standard 310 describes a method for grading a new HVAC system installation. But even if you're not completing a formal grading, it's a good process to ensure you and your team have completed a high-quality installation. The Standard has five steps, which must be performed in order, and in this video, our goal is to provide an overview of each step and show how to make the measurements in the field. We're going to hear from some of the industry's finest, who all have spent years in the field working their way up in the trades, just like me.
Let's get started with step one, which is the design review process. Showing us this step is Adam Muffets from A-Team Heating and Air. Adam has been an HVAC for 20 plus years as an experienced mechanical contractor.
Hey everyone, as Wes said, step one is to complete a design review before the physical evaluation work can be done. Most comfort problems are caused by bad design or by not following a good one. Therefore, one of the best tools for preventing comfort problems and efficiency issues in an existing home is the design process. This means we'll need a completed HVAC design to compare with the blueprints of the build.
One of the best standards for ensuring a good design process is the ACCA ANSI Resnet Standard 310 design review process. Just as you would on a new home, we'll be doing an ACCA Manual J Load Calc on an existing house. And there are several different software packages available which can help us do this. They include RightSoft, Elite, and Quick Model with Energy Gauge. Today, I will show you the one that I use which is Quick Model.
Let's cover the Standard 310 design review questions. If I could answer these questions, I will have gathered the information I need to complete the design review. You may or may not have an existing set of load calcs and duct layouts to work from. If not, you could still use the Standard 310 process to evaluate the as-built conditions.
The first thing I need is a set of plans for the house. If I can locate existing plans, I must first make sure they match the house. If I don't have a set of plans, I will need to create one.
Many production home builders offer options to homes such as extra bedrooms, converting garage bays to living space, and combining rooms to make extra large master suites. These options can substantially change the load of the house and alter the duct layout. Make sure the plans you use reflect the correct final layout of the house. Make sure that the conditioned floor area, window areas, and all of the exterior surface areas that are taken from the plans are reflective to the actual house. For new homes, Standard 310 allows for tolerances of 300 square feet smaller and 100 square feet larger than the current HVAC design, although it should be easy to be more accurate than this.
Make sure you perform your load calculations for the actual orientation of the home. For new construction, the designer will have rotated the orientation around the compass and decided whether different size equipment was needed for different orientations. Typically, they will size equipment for the worst-case orientation. This can lead to oversizing equipment in other orientations if they didn't follow Standard 310.
Perform room by room load calculations. These are crucial to proper air distribution and duct sizing. Indoor design temperatures are 70 degrees heating and 75 degrees cooling. The standard assumption for the number of occupants is the number of bedrooms plus one. Make sure that the number of bedrooms used in the load calculations matches the actual number of bedrooms. Bedrooms are used to determine the fresh air ventilation requirements.
Make sure that you use the windows' solar heat gain coefficients, wall R values, ceiling R values, infiltration plan, etc., that match the actual house. Sometimes the features assumed in the original design are better or worse than what was actually installed.
Review your load calculations to compare the installed capacity of the equipment in the home, and make sure it falls within the guidance of ACCA Manual S.
Okay, with step one complete, we are ready to move on to step two which is to ensure the ducts are not leaky. This step will be completed by Dustin Cole, who is the owner of Cole Air and has over 20 plus years of experience in the industry.
Thanks, Adam. Step two is to make sure we have a tight duct system because if we do not have tight duct work, very well-sealed duct work, we will have comfort and capacity issues. Even if the equipment is set up right, if the ducts are outside of the building envelope, like in an unconditioned attic or a crawl space, leaky ductwork can derate the total capacity of the system.
We do not have that same issue when all of the duct work is inside of the building envelope. But in that case, they can lead to comfort issues due to poor air distribution. So, let's look at how we can complete this test.
Begin with turning the thermostat to the off position. Instead of connecting to my furnace cabinet, in this application, I chose to install my adapter plate to the return air grille with duct mask tape.
Mask off all of the supply registers and any secondary return registers.
Setting up my Duct Blaster® for depressurization testing, this will require installation of the flow conditioner and the ring.
Connect the other end of the flex to the adapter plate mounted on the return air grille.
Install static pressure probe with hose in a supply register and tape in place.
Power up the DuctBlaster, launch tubing assistant from the gauge, and follow the prompts. Connect tubing as shown on screen.
Open an exterior door or window during the test to prevent changes in building pressure while the DuctBlaster is running.
Turn on the speed controller next. Next, initiate cruise feature set for negative 25 pascals. When gauge reaches test pressure, capture the flow measurement.
Report is available with the use of the TEC AutoTest app.
With the test complete, we can put the house back to normal. Close the window, remove duct mask, and turn the system back on.
Now, I'm going to hand this off to Chris Hughes, he is with the Energy Conservatory. He has 20 years of experience in the industry as an HVAC mechanical contractor. Let's see what he has to say.
Thanks, Dustin. In step three, I will be evaluating the total system airflow with the Digital TrueFlow® Grid. There are also three other methods which are recognized by the standard, but the TrueFlow Grid is a great approach because of the consistency of the measurement that it provides, whether it be summer or winter.
Capturing the total system airflow is crucial. Right, and we are going to focus on summer operation, where the fan speed is going to control the balancing act between two types of heat removal from the indoor coil, and that is latent heat and sensible heat.
Let's get to work.
Identify the equipment filter size.
Locate and power up the DG-8 manometer and digital TrueFlow grid. Install the TrueFlow in the correct sized adapter plate.
Launch TrueFlow app and connect to devices. Next, begin your workflow.
Drill a test port in supply plenum and install a static probe. Then, follow the TrueFlow app workflow steps.
Let's complete our app workflow selections. Select equipment type, select orientation, enter the cooling capacity, the air filter location, and design airflow.
Capture supply duct static pressure.
Replace filter with digital TrueFlow grid.
Capture measurement with TrueFlow app.
Report is produced inside TrueFlow app.
Remove the digital TrueFlow grid and reinstall the filter. Don't forget to plug your test ports.
Now that we have confirmed the proper indoor airflow, we are ready for step four. Valerie, the Vice President of Operations at MeasureQuick, will be taking us through this next step.
When we are accomplishing the task of capturing blower fan watt draw in step four, this helps us ensure our system is operating efficiently. During this measurement, to get valid results, it is important that we keep the system operating in the same conditions. We don't want to make any adjustments that would change the operating static pressure against the fan, which, depending on the fan type, will change the flow or change the Watts.
While we are here, let's go ahead and peek at the metering device, so that we can confirm our profile and save ourselves another trip to this attic. Let's get to work.
On this furnace, first, I will remove the combustion compartment door.
I will remove the electrical access cover.
I will set the meter to kilowatts (KW). Attach the meter clamp around the 110-volt wire. Apply one meter lead to ground, and the other lead to power.
Using MeasureQuick, I'm going to connect to my meter and capture the electrical readings. I will use this feature for my Standard 310 report needs.
This report is available using the MeasureQuick app.
Now, let's put things back to normal. Install the electrical cover and put the combustion compartment door back on.
I have spotted a remote sensing bulb. This lets me know that the system has a TXV metering device instead of an orifice.
Let's confirm this data point in our profile, along with the others.
Now that we have our Watts captured in MeasureQuick and our metering device identified, I will pass the final step over to the creator of MeasureQuick himself, Jim Bergman.
So now to complete Standard 310, we want to do a non-invasive test. That's going to require the suction line temperature, liquid line temperature, the outdoor air temperature, return air wet bulb and dry bulb, and supply air wet bulb and dry bulb.
Install the outdoor ambient probe, suction line probe, and liquid line probe.
Install a probe in supply and make sure the probe is installed past the register.
Install a probe at the return air grille and launch the outdoor measurement screen.
Alright, so we have a green flag in MeasureQuick and that means the suction line and the liquid line temperature within the desired range, and we've passed this test for Standard 310.
Items can easily be overlooked or forgotten while working in the field. That's why it's important to have a process, and Standard 310 is a great place to start.