830841-BIM-D-0512
Johnson Controls Unitary Products
27
The unit will continue to operate at full capacity (Gas Heat) until
the thermostat is satisfied. When the thermostat is satisfied, the
gas heat section is de-energized and the DM will operate for a
30 second post purge cycle. At the same time the blower will
operate until the on board Blower Off Delay selection of 60, 90,
120, or 180 seconds expires.
Table 17: Dual Fuel Package Unit Operating Chart
Outdoor Ambient Temperature is Greater than the Balance Point
Control Board
“Y1”
“Y1” + “Y2”
“Y1” + “Y2” + “W”
“Emergency Heat”
YorkGuard VI
Defrost Control Board
(DCB)
Stage 1 Compressor
Full Capacity Compressor
Full Capacity Compressor
“W1 Out” after 4 Hour Pipe
Freeze Timer
“W2 Out” 15 Minutes Later
“W1 Out”
“W2 Out”
after 15 Minutes
When a “Y1” + “Y2” + “W” call are present, mechanical heat is de-energized 30 seconds after the gas heat section is energized and is locked out for
the remainder of the heating call.
Outdoor Ambient Temperature is Between the Balance Point and the LTCO
Control Board
“Y1”
“Y1” + “Y2”
“Y1” + “Y2” + “W”
“Emergency Heat”
YorkGuard VI
Defrost Control Board (DCB)
Stage 1 Compressor
Full Capacity Compressor
“W1 Out”
“W2 Out” after 15 Minutes
“W1 Out”
“W2 Out”
after 15 Minutes
When a “Y1” + “Y2” + “W” call are present, mechanical heat is de-energized 30 seconds after the gas heat section is energized and is locked out for
the remainder of the heating call.
Outdoor Ambient Temperature is Below the LTCO
Control Board
“Y1”
“Y1” + “Y2”
“Y1” + “Y2” + “W”
“Emergency Heat”
YorkGuard VI
Defrost Control Board (DCB)
“W1 Out”
First Stage Gas Heat
“W1 Out”
“W2 Out”
Full Capacity Gas Heat
“W1 Out”
“W2 Out”
Full Capacity Gas Heat
“W1 Out”
“W2 Out”
after 15 Minutes
When a “Y1” + “Y2” + “W” call are present, mechanical heat is not allowed when the Outdoor Ambient Temperature is Below the LTCO.
Defrost Operation
Control Board
Prior to Defrost
During Defrost
“Supplemental Heat”
YorkGuard VI
Defrost Control Board
(DCB)
“W1 Out”
First Stage Gas Heat 30 seconds
before defrost is allowed
“W1 Out”
Gas Heat operates in low fire, Reversing
Valve Energized, Compressor Operates
at full Capacity, Outdoor Fan is De-
energized
“W1 Out” is energized during defrost,
but if the
high side pressure
exceeds
360 PSIG, the gas heat section will be
locked out for the remainder of the
defrost cycle
Compressor Lockout Condition
Control Board
“Y1”
“Y1” + “Y2”
“Y1” + “Y2” + “W”
“Emergency Heat”
YorkGuard VI
Defrost Control Board (DCB)
No Heat until overridden by
the 4 hour pipe freeze timer
No Heat until overridden by
the 4 hour pipe freeze timer
“W1 Out”
“W2 Out”
after 15 Minutes
“W1 Out”
“W2 Out”
after 15 Minutes
