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2630 Airport Road · Kinston, NC 28504
Phone: 252-522-3031· Fax: 252-522-0214
www.fieldcontrols.com
HIGH TEMPERATURE VENT LIMIT SWITCH
Models: LS-140A, LS-550A
Items Included: 1) High temperature vent limit switch 1) TCA-1 thermocouple junction block (LS-550A)
2) 2-1/2 to 5-1/2 inch hose clamps 1) 6 foot length of 12/2 wire (LS-550A)
1) Tube of high temperature sealant 2) Wire hold down clips (LS-550A)
4) Wiring quick connect terminals (LS-140A) 1) ROMEX connector
Installation of a High temperature vent limit switch is recommended for LP and Natural gas fired power
vented and natural draft water heaters. This device is installed to limit the vent temperature in either
plastic pipe (140
0
F temperature limit) or B vent installations (550
0
F temperature limit) caused by scaled
up tanks and/or inadequate venting. Wiring MUST be in accordance with the National Electrical Code and
applicable local codes.
The Field Controls High temperature vent limit switch MUST be installed by a qualified agency in
accordance with the manufacturer’s installation instructions.
The definition of a qualified agency is: any individual, firm, corporation or company which either in person
or through a representative is engaged in, and is responsible for, the installation and operation of gas
appliances, who is experienced in such work, familiar with all the precautions required, and has complied
with the requirements of the authority having jurisdiction.
Before and after adding this safety control on existing appliances, an installation inspection in accordance
with the National Fuel Gas Code 54, Z223.1 Appendix H should be performed and a combustion analysis
is recommended to determine the operating condition of the appliance.
CAUTION: Disconnect Electrical Power When Wiring High temperature vent limit switch
MODEL P/N
CONTACT
MATERIAL
LOAD RATING
LIMIT
SETPOINT °F
RESET
SWITCH
TYPE
APPLICATION
AMPS VOLTS
LS-140A 46564100 SILVER 15 A 120 AC 140 AUTOMATIC SPDT PLASTIC VENT APPLICATIONS
LS-550A 46564200 SILVER 15 A 120 AC 550 AUTOMATIC SPDT B-VENT APPLICATIONS