Has anyone experienced issues with sealed capillary dp transmitters spiking high or low? I believe it is due to the process cooling and thickening at the capsules, but I'm curious to know if anyone else has any viable theories to general causes?

 

Spiking on the wetted side infers pressure and then relief of that pressure. How?

I'd lean towards electronic issues causing spiking, rather than wetted pressure connections.

1. Firmware re-initializing because of DC power supply outage or failure to regulate might cause a spike depending on the initialization process.

2. flakey electronics. It's broken. It only takes one bad transistor out of a million.

3. Theoretically, an intermittent ground loop could pull or drive a current signal off-scale.

30 years ago, I&E guys told me that the city's water pump motor created ground loops during the starting phase which would drive their instrumentation wild (signals would drive off scale) during the motor start period that took a full minute. That was all analog instrumentation at that time.