121
YORK INTERNATIONAL
FORM 100.50-NOM1 (604)
8
BI #12, Filter Status
The Filter Status input will be tied to a differential pres-
sure switch, which will be used to indicate if the
Þ
lters
are dirty. The
Þ
lter status will be indicated as:
• Filter dirty – Filter Status 24VAC input present
• Filter clean – Filter Status 24VAC input not pres-
ent
The control will declare a dirty
Þ
lter fault after the
Fil ter Status input has been present for one min-
ute.
The Dirty Filter Fault will remain active as long as
the Filter Status input is present.
BI #13, Evaporator Freezestat Input
This input is not used on units with the smart relay in-
stalled. The smart relay monitors the freezestat circuit
external to the (Primary Unit Controller).
BI #14, HW Freezestat Input
If the HW (hot water) Freezestat parameter is “ON”
(indicating that a HW Freezestat sensor is installed and
is to be used), the control will monitor this input. The
HW Freezestat input will be interpreted as follows:
• No freeze condition – HW Freezestat 24 VAC in put
present
• Freeze condition – HW Freezestat 24 VAC in put
not present
When the HW Freezestat input opens, the con trol
will:
• Open the Hot Water valve to 100%
• Close the OA damper(s) and open the RA damper
to 100%
• HW Freezestat must close for 5 minutes before the
unit will resume normal operation
• If the HW Freezestat input is open for 10 minutes,
the control will declare a
HW Freeze Fault
, shut
down the unit, and maintain the heating value out put
at 100%.
A
HW Freeze Fault
will remain active as long as the
(hot water) Freezestat input is open. The fault will clear
when the Freezestat input closes for 5 minutes.
HW (hot water) Thermostatic Switch Settings are:
- open @ 35° +4°/-2°
- close @ 47° +4°/-2°
Note: This is an adjustable switch set
(35° to 45°) set at the factory to 35°F.
BI #15, Cool-Heat Changeover Relay Status
The Cool-Heat Changeover Relay (COR) Status input
is used to verify that the relays that route the ON/OFF
commands from the controller to the heating and cool-
ing equipment are as commanded by the controller. To
verify that the changeover relays are as required for
heating or cooling, the control will:
• For cooling operation – verify that the Cool-Heat
COR Status 24VAC input is present
• For heating operation – verify that the Cool-Heat
COR Status 24VAC input is not present
The control will delay 5 seconds from the time
the Changeover Relay control output is switched
before looking at the COR input for the Cool-Heat
COR Sta tus.
If the Cool-Heat COR Status input is not correct, a
COR Fault is declared. The unit is shutdown. The fault
is cleared through manual reset.
BI #16, VFD Bypass Input
This input will be used to signal to the control that
the VFD has been bypassed and the supply fan is now
running full. The control will interpret this input as
follows:
• VFD not bypassed (normal condition) – VFD By-
pass 24VAC input not present
• VFD bypassed – VFD Bypass 24 VAC input present
(24VAC)
When VFD Bypass is present, the control will:
• Shut own all heating and cooling stag es
• Shut down the Supply Fan if operating
The controller will wait 30 seconds from the time of the
above control actions and then restart the Supply Fan
by setting the Supply Fan output to ON (high). Normal
heating or cooling operation will begin.
VFD Bypass operation will continue until the VFD
Bypass input goes low (0 volts). The unit will then
re turn to normal operation.