Subject: Technical Services Department R-32 Compliant Communicating Furnace Updates

This is an important Technical Service Bulletin to be carried out by trained and certified service technicians.  The purpose of this bulletin is to inform our customers about control board changes to our R-32 compliant communication furnaces. ERV / HRV Support for R-32 Compliant Communicating Furnaces (PCBKF321, PCBKF322, & PCBKF324):

An Over-The-Air (OTA) update is now available to provide support for Heat Recovery Ventilators (HRV) and Energy Recovery Ventilators (ERV) when the furnace is used with a communicating thermostat, such as the Daikin One+. HRV/ERV units are designed to provide a 24VAC “G” (fan) call to the HVAC system when ventilation is required. This OTA will allow furnaces being used with communicating thermostats to accept a 24VAC “G” signal from an ERV/HRV and run the blower at the constant fan speed setting when the system is idle (not running in any mode).   Note: Without this OTA, furnaces being used with communicating thermostats will ignore the 24VAC “G” signal from an ERV/HRV. The ventilator will not receive airflow when the system is idle. The OTA is required so the furnace takes the appropriate action when a “G” signal is present.   Note: Systems using standard non-communicating 24VAC thermostats do not require this OTA to provide ERV/HRV support, but there is no harm in providing the update to the system.

See Full bulletin (attached) for the rest of the information.