Low Water Cutoff (Lwco) - Capacitor Electrical Short Test - Aerco Benchmark BMK 750 User Manual

Benchmark 750-3000 Boiler Operation, Service, Maintenance Guide - KOREA
SECTION 4 – MAINTENANCE

4.9.1 Low Water Cutoff (LWCO) - Capacitor Electrical Short Test

This test determines if there is an electrical short between the LWCO capacitor and the heat
exchanger. Perform the capacitor electrical short test as described below.
Low Water Cutoff – Capacitor Electrical Short Test Instructions
Turn the AC power to the unit to OFF
1.
WARNING!
High voltages are used to power these units and so it is required that power applied to
these units is removed first before performing the procedure described in this instruction.
Serious personal injury or death may occur if this warning is not observed.
2. Remove the Shell Harness Cable (male) connector from the P-5 (female) connector on
the rear panel of the C-More Controller (see Figure 4-10).
Figure 4-10: Removing Shell Harness Cable from P5 Conn. on C-More Rear Panel
3. Using an ohmmeter, connect one ohmmeter probe to the LWCO capacitor terminal on
the unit shell as shown on left in Figure 4-11.
4. Connect the second ohmmeter probe to Pin #6 of Shell Harness Connector (removed
from the C-More controller) as shown on right in Figure 4-11.
LWCO PROBE
ASSEMBLY CONNECTOR
Figure 4-11: Connecting Ohmmeter between LWCO Probe & Shell Harness Cable
Page 54 of 146
11/29/2017
.
UNPLUG SHELL HARNESS CABLE
FROM P5 CONNECTOR
OHMMETER
ST
CONNECT 1 LEAD
TO LWCO TERMINAL
CONNECT 2
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
ND
LEAD
TO PIN #6
19-PIN SHELL HARNESS
CABLE CONNECTOR
OMM-0128_0C
GF-206-K