Okay, I've removed the tubes and installed the nuts. Now I am getting 0Ω at 22 which is good. Terminal 13 is odd though. When I first measured it it was reading around 12MΩ and went down to about 8.8MΩ. I removed the probe, waited a few seconds and tested again. It started around 8.2MΩ and went down to the low 7's. Then I took the probe off, waited again and re-tested and it was reading 6.9MΩ and continued to decrease.