Specifications

LWLCWH COLUMBIA BOILER COMPANY REV. 13106

HOT WATER BOILERS

Aquastat

Controllers

All Columbia water boilers and indirect water heaters are controlled by both operating (Honeywell

L4006A-100-240F) and safety limit (Honeywell L4006E 130-290F) Aquastat

Controllers. The safety

limit should always be adjusted higher than the operating limit under normal operating conditions. If

for any reason the water temperature would exceed the operating limit and not trip the control, the

safety limit should break the circuit to the burner.

The operating Aquastat

(Honeywell L4006A-100-240F) consists of an adjustable thermostatic con-

trol and separate temperature sensing immersion well. The immersion well mounts in the boiler s coil

plate. Adjust the indicating dial to set the maximum operating temperature. The differential wheel set-

ting is subtractive from the operating limit indicating the refire temperature. This differential set point

should be adjusted above the required water temperature for the system. The differential wheel can

be adjusted for 3° to 5°F .

The safety limit (Honeywell L4006E 130-290F), like the operating Aquastat

, consists of an adjustable

thermostatic control and separate temperature sensing immersion well. This controller has a manual

reset switch which must be depressed in the event that the operating circuit reached and shut off on

safety.

For additional information on either the L4006A or L4006E, see Honeywell Publication 60-2104-8

following this booklet.

Low Water Cut-off

Hot water boilers utilize the McDonnell & Miller 750-MT-120 Probe Type Low Water Cut-Off with

Remote Sensor. The 750-MT-120 has a test feature that allows this control to meet CSD-1 require-

ments. Similar to the Warrick 26C1C1C, this control breaks the control circuit in the event of a low

water condition and must be manually reset once the proper water level is restored.

For additional information on the McDonnell & Miller 750-MT-120 Probe Type Low Water Cut-Off with

Remote Sensor see McDonnell & Miller Bulletin MM-212(A) and Installation and Maintenance

Instructions MM-213(C).

Relief Valve

Relief valves are a safety devices to relieve boiler water pressure. Like safety valves, relief valves

should be piped so any discharge cannot cause injury to people or damage property. See the “Safety

Valve” description in the Control Descriptions, Steam Boiler section of this booklet.