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KB Home / Equipment / Heat Pumps / York / YZT / YZT - Defrost Board - Push Button Function

YZT - Defrost Board - Push Button Function

Article ID: 718
Last updated: 30 Mar, 2023

York Heat Pump: YZT

Re: Defrost Board - Push Button Functions

The control has a PUSH BUTTON that can be used for various testing functions during installation and service.

The Table below summarizes the behavior of the control when the PUSH BUTTON is pressed.

Press Duration Action with No Thermostat Call Action with Thermostat Call
< 2 sec Display Operational Mode (AC or HP) (5 sec) Display PWM sent to the ODF (5 sec)
2-6 sec Display Current/Stored Fault Code(s) if present.
NOTE: If a fault condition is active, the control will continue to display the active fault. It will not display stored faults until the active fault is cleared.		 Bypass ASCD (Reduce timer to zero immediately).
If Y1 is present and high-pressure switch is closed, the contactor will be energized.
> 6 sec Set Tonnage Configuration (5 sec), ONLY if the Tonnage Configuration fault is currently active.
Set Operational Mode (AC or HP) (5 sec), ONLY if the AC/HP Mode fault is currently active.
The below action will only occur if the above (Tonnage Configuration or Operational Mode) faults are not active when the PUSH BUTTON is held for greater than 6 seconds
Clear Fault Code Memory, if faults are present.		 Initiate defrost cycle, ignore the Liquid Line (Coil) temp.
Defrost cycle is not initiated if O is present.
Energize W1-OUT and W2-OUT and begin defrost cycle immediately upon expiration of timer. This applies only to heat pump systems.
The control will not initiate a defrost cycle when installed in an AC unit.
Clear soft lockout Clear soft lockout; Except Fault Codes 25, 26, and 30.
Clear hard lockout Clear hard lockout; Except Fault Codes 25, 26, and 30.
PUSH BUTTON
signal removed		 Resume normal LED display Complete a Time Temperature defrost cycle if the coil temperature is less than the terminate temperature, or until an O signal is energized.
Terminate defrost normally, if the coil temperature is greater than the terminate temperature, or until an O signal is energized.
PUSH BUTTON
signal not removed		 Display Toggles between Operational Mode (AC or HP) (5 sec) and Tonnage Configuration (5 sec). Continue defrost cycle until PUSH BUTTON connection is removed.
Note: If the PUSH BUTTON is pressed during second-stage anticipation mode, with an active thermostat call, the control will remove the forced second stage.

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Article ID: 718
Last updated: 30 Mar, 2023
Revision: 7
Access: Public
Views: 50
Comments: 0
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