Problem Solving with MurCal

Written by
the murcal blogster
Published on
July 2, 2019 3:18:00 PM PDT July 2, 2019 3:18:00 PM PDTnd, July 2, 2019 3:18:00 PM PDT

Our problem-solving skills were recently put on display when one of our customers experienced failures with their A20 Pressure and Temperature Swichgage® instruments.



Our customer, a commercial bus OEM, installed the A20 Pressure and Temperature Swichgage® instruments in an area of the engine compartment where the ambient temperature exceeded 210°F (99°C) during normal operation. The extreme temperature caused the A20 gauge's polycarbonate case, bezel and lens material to soften. The resulting loss of clamp force between the bezel and lens compromised the integrity of the seal and damaged the Swichgage® instruments.


We analyzed our customer's warranty return records and learned there was a much higher incidence of gauge failure during the hot summer months as compared to the cooler winter season. Our review of the A20 gauge's data sheet led us to advise the customer that the top end of the ambient temperature range for the A20 Series was 150°F (66°C).


We also suggested that finding a secondary location, either inside or outside the engine compartment, where the ambient temperature would not exceed 150°F (66°C) during normal operation would reduce the failure rate of their instruments.