JOHNSON CONTROLS
15
SECTION 3 - TESTING AND ADJUSTMENTS
FORM 160.43-NM4
ISSUE DATE: 11/12/2012
3
6.
Once the DEADBAND setting is verified or cali
-
brated, then repeat steps 2 and 3 noting both the
CUTOUT setpoint and CUTIN Deadband vacu-
um settings to ensure they are both within allow-
able settings ranges. Then proceed to reconnect
the LPCO evaporator pressure connection and
wiring.
Always recheck settings after any adjust-
ments are made.
RECONNECT LPCO EVAPORATOR
PRESSURE CONNECTION AND WIRING
1. Disconnect 1/4 in. refrigerant hose from the 1/4
in. external flare half union fitting at the LPCO
control pressure connection. Remove the control-
lable vacuum source and digital vacuum gauge
assembly.
2.
Ensure 1/4 in. flare mating surfaces are clean and
free of debris or defect.
3.
Reconnect the 1/4 in. flare nut on 90 deg. end
of capillary tube to the 1/4 in. external flare half
union fitting at the LPCO control pressure con
-
nection. Apply tightening torque to the flare nut
only while holding back on fitting. Secure flare
nut to fitting tight enough to ensure a leak free
seal.
4. Disconnect the Ohm meter from the switch Com-
mon and Normally Open terminals.
5. Connect the wire numbered 47 to the 025 45742
LPCO control switch terminal labeled as COM-
MON. Refer to Figures 1, 3 and 4 and ECC Wir-
ing Diagram.
6. Connect the wire numbered 48 to the 025 45742
LPCO control switch terminal labeled as NOR-
MALLY CLOSED. Refer to Figures 1, 3 and 4
and ECC Wiring Diagram.
7. Connect the wire numbered 49 to the 025 45742
LPCO control switch terminal labeled as NOR-
MALLY OPEN. Refer to Figures 1, 3 and 4 and
ECC Wiring Diagram.
8. Reinstall enclosure cover securing with the one
captive screw located on the front of the cover.
Refer to Figures 2 and 3.
RETURN CHILLER TO SERVICE
1. Reverify that LPCO adjustments piping and wir-
ing work performed has been done completely and
accurately and chiller is ready to return to service.
2. Open the evaporator service valve having gauge
piping going to the “Cooler” (evaporator) panel
gauge and LPCO control.
3. Leak check all ECC and LPCO piping connec-
tions with ultrasonic leak detector. Correct any
leaks found before returning the chiller to service.
4. Replace ECC fuses 1FU, 2FU and 3FU. Remove
Lock-Out, Tag-Out from the chiller.
5. Turn on power source feed to the chiller Electron-
ic Control Center (ECC).
