From time to time, the issue of accurate temperature calibration of the PRIMUS Sanitary Drain RTD (typically used on cGMP validatable sterilizers) is reported from the field.

This Sanitary Drain RTD (PRIMUS P/N 400738) has a long insertion length which is typically needed to reach the center of a CIP tee or cross. This length can be an issue when performing temperature calibration using a typical dry well calibrator.

Importance of Proper Calibration Method

It is very important to achieve accurate temperature calibration of the Sanitary Drain RTD in a cGMP sterilizer as this is the controlling temperature element.

Inaccuracies in calibration typically lead to a sterilizer that operates either too cold or too hot. This is typically revealed through chamber mapping. Either scenario could cause a sterilized load to be rejected and could potentially trigger a product recall in certain circumstances.

Required Process/Options

The RTD manufacturer strongly recommends (requires) insertion of the Sanitary RTD up to the Sanitary Flange to ensure accurate temperature calibration.

With the required 6″+ insertion length, PRIMUS has found many drywell calibrators cannot accommodate the entire length.

Two recommended solutions are:

  • Option #1 – purchase a drywell calibrator capable of insertion up to the Sanitary Flange
  • Option #2 – some Pharmaceutical customers utilize an oil bath or fluidized sand bed calibration equipment

PRIMUS’ guidance is to make sure that the Sanitary Drain RTD is totally immersed in the temperature calibrator (regardless of type) up to the flange. This will provide for accurate calibration of the Sanitary Drain RTD and will ensure that the PRIMUS control system operates at peak efficiency.

Have a question or having difficulties? Talk to Dave Schall, our PRIMUS sterilizer expert who is here to assist you anytime at 877.679.7800 extension 1212 or email at dschall@spire-is.com.

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