Johnson Controls yzh Fascicule

Subject to change without notice. Published in U.S.A.

035-22286-001-A-0909

Copyright © 2009 by Johnson Controls, Inc. All rights reserved.

Supersedes:Nothing

OUTDOOR UNIT MODIFICATIONS

1.

Disconnect all high and 24V voltage power to the unit and
the control circuit.

2.

Mark and disconnect all thermostat, sensor and low volt-
age control connections from the YorkGuard IV control.

3.

Remove the six #10 screws holding the control and remove
the control.

4.

Using five of the six screws removed in Step 3, mount the
new board in place (omit the top middle screw).

5.

Reconnect the wires removed in Step 2.

INDOOR UNIT MODIFICATIONS

NOTE:  Indoor transformer should be rated for a minimum of
40VA. Replace transformer if necessary.

FOSSIL FUEL APPLICATION - The YorkGuard VI control does
not require an add-on fossil fuel kit. Remove existing fossil fuel
kit if present. An optional bonnet sensor may be used if desired.
See “OPERATION INSTRUCTIONS - “DEMAND DEFROST
CONTROL BOARD” on upgnet.com for details of functionality
with and without bonnet sensor installed.

START-UP OPERATION

1.

Reapply power to the unit and the control voltage circuit.

2.

The LED on the defrost control will flash on and off when
there is power to the control and it is working properly.

3.

Verify unit operation.