BY GEORGE LANTHIER
Figure 10
Figure 9
capabilities. Unlike other scales, which emphasized a need to increase the number of particles passing through an air filter, MERV was designed to offer a balance between particle filtering and energy efficiency. A MERV rating is important because it helps you understand an air filter’ s effectiveness so you can choose the right one for your customer’ s particular needs. For example, if your customer has someone in the home who suffers from allergies, you may want a higher MERV rating. The MERV scale also helps balance the air quality and energy efficiency needs of the home.
Running the fan, all the time can make the HVAC system last longer by reducing wear and tear. New energy-saving HVAC motors are made for constant use and can lower the monthly energy bills. Check out PSC and ECM motors for more info and check what’ s available from a manufacturer before you replace a furnace.
For people with allergies, running the fan, all the time can make the air cleaner and easier to breathe if the home is equipped with the right MERV filter or even better an electronic air cleaner. But there are downsides to think about too. Running the fan, all the time uses more energy and means you’ ll need to change filters more often.
The idea is to keep air moving, which promotes better air circulation and with humidifiers and electronic air cleaners( EACs) a healthier air flow through the home. The operation of this function is quite unique and simply requires a thermostat with heat-cool functions.
Using the‘ CONT’ terminal, Figure 1 and Figure 7 again we see that Resideo has the lowest speed of the circulating fan attached to this terminal. Basically, the operation is that the circulating blower at low speed is energized when there is no call for heat and no call for cooling. If blower operation is required by a call for heat or a call for cooling the control switches the circulating fan to the appropriate speed.
Finally, it must be noted and strongly stressed that when troubleshooting these boards from any manufacturer only use a meter and be careful where you place the probes for testing. In addition, and based on some embarrassing personal moments over the years be aware that most of the boards I’ ve run into are polarity sensitive, very! When they act a bit‘ weird’ check your line voltage wiring and be careful of crossed polarities. Most of this two-part article is taken from our training manual called‘ The Warm Air Handbook’ and is included in our‘ Warm AIR Controls for GAS & OIL’ seminar. See ya! l FON
George Lanthier is the owner of Firedragon Academy. For more information, visit www. FiredragonEnt. com.
32 JULY 2025 | FUEL OIL NEWS | www. fueloilnews. com