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3 Ways to Measure Airflow for Rooftops and Other HVAC Equipment

One of the most common reasons for rooftop service calls is incorrect airflow.  Low airflow will often lead to frozen evaporator coils, low pressure trips, sweating ductwork and low...... Read More

Can you use a standard rooftop for a makeup air application?

We get asked this question often. And for good reason, DOAS equipment is expensive.  If a building owner needs makeup air, in most cases a DOAS will be required....... Read More

Did you know: Hot Gas Reheat provides NO benefit on a design day?

Did you know: hot gas reheat operation (for dehumidification) provides NO benefit on a summer design day? This can be an easy mistake to make. (to clarify from the start, this is NOT...... Read More

How to Pipe a Single Circuit A/C with a Dual Circuit Evaporator Coil

If you’re installing a split commercial DX system, how do you know what kind of circuiting you need? And how do you install the piping and refrigerant specialties if...... Read More

Did You Know – Phasing Revised

When It Comes To Three Phase Equipment Did You Know: Three phase power distribution requires smaller conductors for transferring the same amount of power as compared to single phase...... Read More

How to Calculate Cooling Capacity for a DOAS unit

This is an easy calculation if you know the cfm (airflow to be conditioned) and have a psychrometric chart handy.  The formula for calculating total cooling is: Qt = cfm x (Hf-Hi)...... Read More

HVAC Rules of Thumb

If you’ve been in the HVAC industry for a while, you probably have some “Rules of Thumb” that you use throughout your day. Here are a few that you...... Read More

How to design a DOAS unit as sole source heating and cooling

When possible, it makes life easy to have a separate DOAS system from the space HVAC system. In this case, each system has one specific job: -The DOAS’s job is...... Read More

DYK York doesn’t require suction traps for R410a?

When an HVAC system uses POE (Polyolester) oil, which is typical of current R410a systems, suction oil traps are not required* because POE is miscible in R410a in all phases...... Read More

Fan Types- Centrifugal, Axial, Forward Curve, Airfoil. What does it all mean?

The cfm Distributors Inc Applied Systems Group meets every other Monday at 8am for training. This training covers a plethora of topics, but a portion of this training is...... Read More

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