ONICON Incorporated 727-447-6140
Page 13
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SYSTEM-20 BTU METER
Removal of the Hot Tap Thermowell
WARNING (16)
Maintain a firm hold on the wiring enclosure until the thermowell is
completely withdrawn and the valve is closed.
1.
System pressure will try to push the thermowell out of the flow stream
when the clamping nut is released. Be sure to establish safe footing prior to
loosening the clamping nut. The force pushing out against the thermowell is
the same as the insertion force.
2.
Grasp the wiring enclosure firmly, holding the thermowell in the pipe and
then loosen the position clamping nut. Slowly withdraw the thermowell from
the pipe.
3. After the thermowell is completely withdrawn, carefully close the isolation
valve.
IMPORTANT NOTE
(17)
Rotating the thermowell as you slowly withdraw it through the valve will
ensure that the lower tip is fully withdrawn and completely free of the valve.
If resistance is felt when closing the valve, open valve fully and rotate the
well as you pull it further out of the pipe.
3.2.3 Temperature Sensor Installation
When ordered with the System-20, temperature sensors are factory matched and
tagged by serial number to a specific Btu meter. ONICON standard temperature
sensors are also designated and labeled as the SUPPLY or RETURN sensor and
must be installed per these labels.
3.2.3.1 ONICON Standard Temperature Sensor Installation
ONICON standard temperature sensors must be used as a pair to
maintain differential accuracy. They are also designated and labeled as
the SUPPLY or RETURN sensor and must be installed accordingly. To
install, apply a thin coat of thermal compound to the sensor tip area and
insert it all the way into the thermowell until it contacts the bottom of
the cavity. Gently tighten the retainer nut. DO NOT OVERTIGHTEN. The
thermowell completely seals the plumbing system without the retainer
nut. The only purpose for the nut is to ensure that the sensor tip will
remain in contact with the bottom of the thermowell.