Configuration (Jumpers And Potentiometers); Fig. 15 - Potentiometer Settings - York YCAL Series Installation Operation & Maintenance

SECTION 8 - UNIT OPERATION
The VFD will ramp up the speed of the fan as pres-
sure rises above the low end of the speed control range.
Throughout the pressure control range, the VFD con-
trols the speed of the fan based on discharge pressure in
the range of approx 160-180 psig. At pressures above
180 psig, the VFD will run the system fan at full speed.
As pressure drops below 180 psig, the VFD will slow
the speed of the fan to try to maintain discharge pres-
sure within the control range. The VFD will try to
maintain pressure in the range of 160-180 psig by rais-
ing and lowering the speed of the fan. If pressure drops
below 160 psig, the VFD will virtually turn the system
fan completely off. Some slight fan movement or very
slow rotation may be noted, although the fan may ap-
pear to stop completely.

Configuration (Jumpers and Potentiometers)

Each VFD is pre-configured at the factory prior to ship-
ping and should be ready for operation when it arrives
onsite. A quick check of the settings is recommended.
The jumpers must be in the positions shown in the fol-
lowing Table.
Chillers built in 2005 and early 2006
were configured with J4 IN. This
jumper must be removed. Also be sure
to check J2 and remove if necessary.
VFD JUMPERS
J2 Remove
J3
J4 Remove
J5
J6
J7
J8
J9 IN for 60Hz
138
-
IN -
-
IN -
IN -
IN -
IN -
Remove for 50Hz
POTENTIOMETER SETTINGS
P1
180 PSI
P1 P1
P2 P2
FIG. 15 – POTENTIOMETER SETTINGS
Potentiometer settings are also preset at the factory.
The potentiometers should be in the positions shown
in Fig.15. The pots do not have numerical settings and
are set according to the arrow positions indicated. DO
NOT change the potentiometer settings unless they do
not match the positioning of the potentiometers shown
in Fig. 15. P1 should be full CW (180 psig) and P2
should be full CCW (20 psig). Modifying these settings
may cause damage to the chiller or control problems.
The P1 pot sets the setpoint which is the top end of the
control range. This setting is the discharge pressure at
which the fan will be operating at full speed. The P2
pot sets the range. This is the range of pressure where
the VSD modulates the fan speed from 0 RPM to full
speed. The range is subtracted from the setpoint to cal-
culate the 0 RPM pressure.
FORM 150.66-NM3
ISSUE DATE: 09/25/2020
P2
20 PSI
LD11300A
JOHNSON CONTROLS