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LEAD/LAG OPERATION:
When two hot water boilers are set-up for lead/lag operation, a hot
water temperature sensor must be installed for each boiler.
STANDBY WATER TEMPERATURE
1.
Disconnect power to the boiler controller so the boiler cannot sequence during installation of the
standby temperature sensor.
2.
The thermowell must be mounted where it is always exposed to the circulation of the hot water.
3.
If the water system is full, drain the system below the point where the thermowell will be
installed.
4.
Tap an appropriate size fitting (2", 4" and 8" thermowells have 1/2" NPT fitting).
5.
Insert the appropriate thermowell (2", 4", or 8") and tighten.
STACK TEMPERATURE
1.
Use the existing well connection for the stack temperature sensor if provided by the boiler man-
ufacturer.
2.
If no well connection is provided, select an appropriate location for mounting the temperature
sensor. Preferably as close to the boiler outlet as possible.
OUTDOOR AIR TEMPERATURE
1.
The outdoor air temperature sensor should be mounted on the outside of the building where it
will be exposed to representative air temperature, but not to direct sunlight. A sun shield may be
required.
2.
Mount the temperature sensor high enough so it cannot be covered with snow, leaves, or other
debris, or be tampered with. Vents from the building should be avoided.
WARNING: Location of the temperature sensor to monitor boiler water temperature of a
steam boiler is critical. The sensor should be mounted where it is always exposed to the cir-
culation of the boiler water, not too close to a hot or cold inlet or steam coil. Consult the
boiler manufacturer for guidance on the sensor location.
