SECTION 8 - MICROPANEL
JOHNSON CONTROLS
151
Form 201.28-NM1.1
Issue date: 08/06/2021
8
LD10605
Program key
Program key
Program key operation
Various operating parameters are programmable by the
user. These are modified by pressing the PROGRAM
key and then the
(ENTER) key to enter Program
Mode. A listing of the limits of the programmable val-
ues is shown in
. Note that the Imperial units
are exact values, while Metric units are only approxi-
mate.
The ▲ and ▼ (
ARROW) keys are used to scroll
through the user programmable values. A value may be
changed by keying in the new value and pressing the
(ENTER) key to store the new value in memory. The
cursor will be displayed on the screen when a number
key is pressed. The first line of each message will indi-
cate the chiller default (DEF) value, lowest acceptable
programmable value (LO), and highest acceptable pro-
grammable value (HI). The user programmable value
is programmed ON in the second line of the message.
When the PROGRAM key is first pressed, the follow-
ing display will appear indicating the user is in the pro-
gram mode:
PROGRAM MODE XXXX
PRESS ENTER KEY TO CONTINUE
To display the first programmable selection, press the
(ENTER) key again.
Suction pressure cutout
PROGRAM ◄DEF XXXXX LO XXXXX HI XXXXX
SUCTION PRESSURE CUTOUT = XXX.X PSIG
The suction pressure cutout is protects the chiller from
a low refrigerant condition. It also helps protect from
a freeze-up due to low or no chilled liquid flow. How-
ever, it is only a back-up for a flow switch and cannot
protect against an evaporator freeze under many condi-
tions. This cutout is programmable and should gener-
ally be programmed for 1.65 barg (24 psig) for chilled
water cooling for R-134a system, and 1.93 barg (28
psig) for R-513A system.
For R-134a refrigerant, the cutout is programmable be-
tween 1.65 barg and 2.48 barg (24.0 psig and 36.0 psig)
in the Water Cooling mode and 0.34 barg and 2.28 barg
(5.0 psig and 36.0 psig) in the Glycol Cooling mode.
The default value for both modes will be 1.65 barg
(24.0 psig).
For R-513A refrigerant, the cutout is programmable
between 1.93 barg and 2.80 barg (28.0 psig and 40.7
psig) in the Water Cooling mode and 0.53 barg and
2.80 barg (7.7 psig and 40.7 psig) in the Glycol Cool-
ing mode. The default value for both modes will be
1.93 barg (28.0 psig).