Yes, that's the tester I am using. You have been very kind and patient in sharing you expert knowledge. I did tap the gauge before finally reading. But I am now going to go back at this armed with the insights you have provided. The aim is to examine the trailer's system to see if anything other than the stove regulator could be contributing to the stove issue. The new part has been installed in the stove, but it will have to go back to high elevation to really be tested. As you might surmise, I am retired with too much time on my hands!
Many thanks,
Shane