York Air Handler: MP, MX, MV, AHP, AHX, AVY Re: Auxiliary Heaters Not Working The 4HK heater kits for these air handlers consist of In-line beakers, a control board, snap-disc limits, and DC voltage relays. The control board has two heat stage inputs, "W1" and "W2". In some instances, "W1"...

York Air Handler: AHX, AHP, AVY, MX MA Re: Directional Heat Issue Problem Description: Blows cold air in emergency heat and defrost Observed Symptoms: Air handler with supply going two directions (see attached drawing) Problem with electric heat only Duct to the back of the air handler...

York Air Handler: AHP/MP Re: Flashing Code 2 The control board in the air handler monitors the limit switch in the aux heaters. Code 2 = Limit switch opened two times with NO CALL FOR HEAT. ► This is a Hard Lockout condition that will keep all heater outputs off. ► The blower will...

York Air Handler: AHP/MP Re: Flashing Code 3 The control board in the air handler monitors the limit switch in the aux heaters. Code 3 = Limit switch opened multiple times during a single call for electric heat. ► The control will energize the blower until power is removed from the...

York Air Handler: MP, MX, MV, AHP, AHX, AVY Re: Fan Runs Continuous, Flashing Code 4 Code 4 = Extended Limit Trip The control board in the air handler monitors the limit switch(es) in the aux heaters. If the limit switch opens for a long duration (fault code 4), the control will energize...

York Air Handler: MP, AHP Re: Won't Stop Heating/Runs Continuous The auxiliary heaters are controlled by a computer board and DC voltage relays. Qty Possible Causes: 1 Bad Thermostat Shorted Low Voltage Bad Heater Relays Bad Heater Control Board ...