Columbia CWH series, Installation, Operation And Maintenance Manual, Page: 11 / 56

LWLCWH COLUMBIA BOILER COMPANY REV. 13106
8
BOILER CONNECTIONS
Drains
All Columbia Boiler units have (4) washouts located around the lower corners of the boiler for drainage
purposes. Install a pipe nipple and ball valve in a least one washout for use as a drain. If a washout
is not needed, plug it by using the proper size nipple and a pipe cap. DO NOT use a pipe plug.
Low Water Cut-Offs
All Columbia boilers are supplied with a single low water cut-off (LWCO) as standard equipment.
Several boiler applications may require a secondary LWCO. The standard equipment is as follows:
Hot Water Boilers - McDonnell & Miller 750-MT-120 Probe Type Low Water Cut-Off with Remote
Sensor - Thread the Remote Sensor into the 3/4” NPT fitting located on top of the boiler. Mount the
Control Box near the top of the front jacket panel (or upper front jacket panel on some units).
Steam Boilers - McDonnell & Miller Model 767 Quick-Hook-Up Low Water Cut-Off - Install this device
into the 2-1/2” NPT welded coupling found on the coil plate for L Series boilers, and on the left hand
side of the heat exchanger for WL Series boilers.
Water Heaters - McDonnell & Miller Model 767 Quick-Hook-Up Low Water Cut-Off - Install this device
into the 2-1/2” NPT welded coupling found on the coil plate for CWH-170 / -610 Series boilers, and
on the left hand side of the heat exchanger for CWH-780 / -2460 Series boilers.
Secondary Low Water Cut-Offs
Secondary LWCO s may be required to meet local codes or CSD-1 requirements. A Warrick 26C1C1C
Probe Type Low Water Cut-Off is used in steam applications to meet CSD-1 requirements. Thread the
remote sensor into the 1/2" NPT fitting located on top of the boiler using a 1/2" x 3/8" bushing. See
Table 1. for proper probe rod length. Mount the control box to a front or side jacket panel on the
boiler.
LENGTH OF PROBE ROD IN “L” AND UP TO” CWH-610” SERIES BOILERS
BOILER L-18 L-20 L-22 L-24 L-30 L-32
MODEL CWH-170 CWH-240 CWH-300 CWH-390 CWH-475 CWH-610
ROD LENGTH 4-7/8" 6-1/4" 6-1/4" 6-1/4" 7" 9-5/8"
Table 1a