HVAC system and method of circulating flammable refrigerant

A method for a heating, ventilation, and air conditioning (“HVAC”) system, the method comprising:

• determining, by one or more controllers of the HVAC system, an air flowrate of an air blower of the HVAC system;
• upon determining, by the one or more controllers, that the air blower cannot provide an air flowrate equal to or above a comfort setpoint operate the air blower at the minimum required air flowrate:
• determining, by the one or more controllers, an external static pressure of the HVAC system when the air blower is operating at the minimum required air flowrate;
• and
• in response to determining that the external static pressure of the HVAC system exceeds a maximum external static pressure of the HVAC system, sending, by the one or more controllers, a notification to an operator of the HVAC system indicating that external static pressure of the HVAC system exceeds the maximum external static pressure of the HVAC system.

A controller comprising processing circuitry and a computer readable storage medium comprising instructions that, when executed by the processing circuitry, cause the controller to:

• determine an air flowrate of an air blower of the HVAC system;
• upon determining that the air blower cannot provide an air flowrate equal to or above a comfort setpoint operate the air blower at the minimum required air flowrate:
• determine an external static pressure of the HVAC system when the air blower is operating at the minimum required air flowrate;
• and
• in response to determining that the external static pressure of the HVAC system exceeds a maximum external static pressure of the HVAC system, send a notification to an operator of the HVAC system indicating that external static pressure of the HVAC system exceeds the maximum external static pressure of the HVAC system.