A potential problem with thermowells is incorrect installation of the temperature-sensing element.
The element must be inserted with full contact at the bottom of the thermowell’s blind hole. If any
air gap is allowed to exist between the end of the temperature element and the bottom of the
thermowell’s hole, this will add a second time lag to the measurement system26. Some thermowells
include a spring clip in the bottom of the blind hole to help maintain constant metal-to-metal contact
between the sensing element and the thermowell wall.