Safety Thermostat - Carrier 30HS Series Installation, Start-Up And Service Instructions Manual

MANUAL
RESET
BUTTON
HIGH PRESSURE
LOW PRESSURE
CONNECT TO
OIL PUMP
DISCHARGE
CONNECT TO
CRANKCASE
OIL
PRESSURE
SWITCH
TERMINAL
CONTROL BOX TERM.
OR CONNECTION
070 - 090 I 100-160
COMPRESSOR NUMBER
3 3
63 23 63 35
rq
31
61
31
62
32
62
32
53 30 53 42
STOP LUG
DIAL
SCREWS
SCREW
"A"
RESET
BUTTON
FIXED INDICATOR
ADJUSTING SLOT
Open 115-volt control circuit breaker and all
compressor circuit breakers. Remove all oil pres-
sure safety switch (OPSS) covers and disconnect
the wire at the 120-volt terminal of each OPSS.
Check each control as follows: reconnect the L2
wire to 120-v terminal of OPSS no. 1 and close
115-volt control circuit breaker. Energize the
control circuit by pressing the START-STOP
button to START. Sequencer energizes compressor
no. 1 contactor(s) and indicator light; heater in
OPSS is now energized. In approximately 45
seconds, warp switch in the control opens, de-
energizing the contactor(s) and light.
If con-
tactor(s) remains energized more than 60 seconds,
the control should be replaced.
Allow approximately 5 minutes for the thermal
switch to cool, then manually reset the control.
Open the 115-volt control circuit breaker and dis-
connect the L2 wire from the 120-v terminal. Repeat
test procedure for each remaining OPSS control.
When test has been completed, reconnect all
OPSS controls at 120-v terminal and replace covers.
Do not attempt to field repair a control that
requires service. Contact your local Carrier
representative.
(Switch shown is Penn Controls.)
Fig. 5 — Oil Pressure Safety Switch
SAFETY THERMOSTAT
The low water temperature cutout (Safety
Thermostat, Fig. 6) is a noncycling, manual-reset
type, to protect against freeze-up due to operating
malfunction. On all units, bulb is installed in leaving
chilled water connection (item 8, Fig. 1). Freezestat
is set to break control circuit at 36 ± 2 F, locking
out unit. The thermostat must be reset before unit
can restart. The chilled water circulating pump con-
tinues to operate during lockout period.
Table 3 — Wiring Connections, Oil
Pressure Switch
Terminal on terminal strip in control box.
NOTES:
1. Wire from switch terminals to indicated terminals or connec-
tions in unit control box.
2. Refer to wiring label on unit.
Fig. 6 — Safety Thermostat
For glycols, or brines, loosen screw "A" (Fig. 6),
hold stop lug against fixed indicator and turn dial
to lower setting. Tighten screw "A."
Do not disturb
this screw for any other adjustment.
Check thermostat at installation and at least
once each season thereafter.
To Check — Insert screwdriver into adjusting slot
and turn dial assembly until desired cutoff tempera-
ture is directly under fixed indicator.
Place bulb
in vacuum bottle filled with mixture of water and
crushed ice. Stir mixture with thermometer; as ice
melts, temperature of mixture will go down. Note
temperature where thermostat cuts out. This should
be within 1 F or 2 F of dial setting. Recalibrate
if variation is greater.
it
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