As you are probably aware, the most vulnerable part of an ECM motor is the control module. With energy requirements becoming tighter and tighter, ECM motors are becoming the standard rather than the occasional motor of choice. Early on, it was found that the most common failure of an ECM motor was the control module. Back in October of 2006, we started to add what is called a “choke coil” to all furnaces with 3/4 and 1 HP ECM motors. The addition of the choke coil has greatly reduced repeat motor module failures.
So, what is a PF choke coil?
PF (Power Factor) is a fraction of power actually used by electrical equipment compared to the total apparent power supplied, usually expressed as a percentage. A power factor indicates how far the electrical equipment causes the electric current delivered at the site to be out of phase with the voltage. The ‘PF Choke’ is used to reduce this ’Out of Phase’ or , in other words ‘Choke’ the Power Factor coming into ECM Module preventing the burn out of its electronics.
As I mentioned earlier, we have had these on all of our furnaces with the larger HP ECM motors since 10/06 but there are probably a lot of furnaces out there before this was initiated that do not have the PF Choke Coil.
If you have a site that has had ECM module failures with either the 3/4 or 1 HP ECM motors, then you might want to consider installing a PF Choke Coil on that unit to help prevent future failures. The replacement Power Factor, PF, Chokes for 1600 CFM Units with 0.75 HP ECM Motors: 11 Amps;is our part number S1-024 35605 000. For 2000 CFM Units With 1.00 HP ECM Motors: 12 Amps;the part number is S1-024 35604 000
It is not normally necessary for 120 VAC 1200 CFM units with 0.50 HP ECM Motors or any 240 VAC applications to need a choke. However, The following kit can be added to help resolve all problem applications. That kit number is S1-324 35604 000.
Keep in mind that this is not a “cure-all” for power surges or other power problems, but this will help alleviate repeated module failures if there is not a Choke Kit already installed on the furnace.
One last thing, these kits will work with ANY manufacturer’s ECM motor that may be experiencing failures.