Advantage Sentra SK Series, Instruction Manual

Page: 48 / 70

Temperature Control Units : Sentra with VE Series Instrument
Page: 48
Advantage Engineering, Inc.
525 East Stop 18 Road Greenwood, Indiana 46142
317-887-0729 Fax: 317-881-1277
Service Department Fax: 317-885-8683
www.AdvantageEngineering.com
5.6 PRESSURE SWITCH SERVICE
A. The unit is protected from low pressure operations by a
pressure switch (figure 5.6A). This switch is mounted at
the bottom of the electrical cabinet.
B. The switch will close and consent the control circuit
when sufficient water supply pressure is presented. The
switch is factory set to 20 psi.
C. If insufficient water supply pressure is present, the
switch will open and prevent operations.
D. In cases where sufficient water supply pressure is present as indicated by the unit’s
pressure gauges and the pump is “off”, and if the pressure switch fails to close, the
pressure switch may be defective. To replace the pressure switch, follow the steps
outlined:
1. Shut down unit operations according to section 3.4 in this manual. Be certain
proper lock-out procedures are followed. Also, be certain system pressure is
eliminated and the unit’s pressure gauges read “0” pressure.
2. Drain unit by removing the pump casing drain plug.
3. A capillary runs from the cooling cylinder to the pressure switch. Remove the
capillary connection.
4. The brass elbow mounted on the pressure switch must be removed.
5. Remove the electrical connections to the pressure switch.
6. The pressure switch is mounted onto the electrical cabinet with two 1/2” nuts in
series. Remove the nuts to remove the pressure switch. A new pressure switch
from the factory should be installed by continuing with step 7.
7. Thread one 1/2” nut onto the pressure switch and then place the pressure switch
through the panel in the original mounting hole. Thread the second 1/2” nut from
the bottom of the pressure switch. Tighten to lock the pressure switch in place.
8. Install the brass elbow fitting. Teflon tape and leak preventative paste should be
used to prevent water leakage. Install the capillary tube and resume operations.
Pressure switch
Figure 5.6A