Knowledgebase

YZT Status Codes / Fault Codes

Article ID: 717
Last updated: 31 Mar, 2023

York Heat Pump: YZT

Re: Communicating Defrost Board 


Fault Code Memory:

  • The control stores the 10 most recent fault codes in memory.
  • The codes are stored even when power is removed from the control and will remain in memory until they are manually cleared from the control.
  • All codes are time stamped and stored in order of occurrence.
  • The control stores only one identical fault code during the same series of events. For example, if two or more low temperature cutout faults occur sequentially without another fault occurring in between the low temperature cutout faults, the control only stores the low temperature cutout fault once.
  • The stored faults can be displayed by pressing the PUSH BUTTON for two to six seconds, without a call for compressor operation.

Status Code Display
LED Segment 1 Segment 2 Description
Off No power to control
2s on 2s Off Normal operation - No call for compressor
0.1s On 0.1s Off d 5,4,3,2,1 COOLING Short-cycle delay timer
0.1s On 0.1s Off d 5,4,3,2,1 HEATING Short-cycle delay timer
On C 1 COOLING 1st Stg Compressor Operation
On C 2 COOLING 2nd Stg Compressor Operation
On H 1 HEATING 1st Stg Compressor Operation
On H 2 HEATING  2nd Stg Compressor Operation
On A 1 Aux Heat 1 (below BP)
On A 2 Aux Heat 2 (below BP)
On d r COOLING Demand Response (Utility input)
On d r HEATING Demand Response (Utility Input)
On E 1 Emergency Heat Stg 1
On E 2 Emergency Heat Stg 2
On o r Oil Return
On d d Demand Defrost
On d c Calibration Defrost
On t d Time & Temperature Defrost
On F d Forced Defrost

Operational Fault Codes
LED Segment 1 Segment 2 Description Control Response
On 0 0 Control Failure None
On 0 1 High-pressure switch (not in lockout yet) None
2 flash 0 2 2 High-pressure faults in 6 hours Soft Lockout
3 flash 0 2 4 High-pressure faults in 12 hours Hard Lockout
2 flash 0 3 2 DEFROST High-pressure faults in 6 hours Soft Lock
3 flash 0 3 4 DEFROST High-pressure faults in 12 hours Hard Lockout
2 flash 0 4 Low-pressure switch fault Soft Lockout
3 flash 0 4 4 Low-pressure faults in 12 hours Hard Lockout
On 0 5 LTCO Active None
On 0 6 Low Voltage < 19.2VAC None
On 0 7 Low Voltage < 16VAC None
On 0 8 Pipe Freeze Protection None
On 0 9 Outdoor Sensor shorted in Cooling ODF operates at Max
On 0 9 Outdoor Sensor shorted in Heating None
2 flash 0 9 Outdoor Sensor shorted in Heating Soft Lockout
On 1 0 Outdoor Sensor Open in Cooling ODF operates at Max
On 1 0 Outdoor Sensor Open in Heating None
2 flash 1 0 Outdoor Sensor Open in Heating Soft Lockout
2 flash 1 1 Coil Sensor Shorted Soft Lockout
2 flash 1 2 Coil Sensor Open  Soft Lockout
2 flash 1 3 Discharge Sensor Shorted Soft Lockout
2 flash 1 4 Discharge Sensor Open Soft Lockout
On 1 5 Discharge Temp > 263 F None
2 flash 1 5 Discharge Temp > 263 F (3 times) Soft Lockout
3 flash 1 5 Discharge Temp > 263 F (12 times) Hard Lockout
On 1 6 Discharge Temp < 90 F None
2 flash 1 6 Discharge Temp < 90 F (3 times) Soft Lockout
3 flash 1 6 Discharge Temp < 90 F (12 times) Hard Lockout
2 flash 1 7 Bonnet Sensor Shorted Soft Lockout

Wiring-related Fault Codes
LED Segment 1 Segment 2 Description Control Response
2 flash 1 8 O Received in A/C Only Mode Soft Lockout
2 flash 1 9 W Received in A/C Mode Soft Lockout
2 flash 2 0 W & O Received in A/C Mode Soft Lockout
2 flash 2 4 W & O Received in  H/P Mode Soft Lockout
2 flash 2 5 Was A/C Mode, Now H/P Mode Operates in A/C Mode
On 2 6 Was H/P Mode, Now A/C Mode Operates in Heating

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Article ID: 717
Last updated: 31 Mar, 2023
Revision: 5
Views: 135
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