Welcome! Here are the website rules, as well as some tips for using this forum.
If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
York RTU Gas Heat Quandry
We had an installation that required converting 2 York RTU's from Natural gas to propane. This was done and ran successfully for about a year. They recently got NG on site and I was asked to convert it back. I just reversed the procedure, which was the springs in the valve, the original orifices, and two plates which move the burner assembly out a little bit. New gas pressure is 2 PSI to the regulator, bumped down to 7 inches. Manifold pressure is 3.5 inches on high fire. DC miliamps at 3 while fired. The problem is it runs for a minute and craps out. Does this 4-5 times and locks out. Checked grounds. No luck. Bled line for about a half hour as it is about 200 feet. New sensor, no luck. New unused board, no luck.
These are York ZF090N18R2B6AAA1A2 units. Little over a year old. Any help would be wonderful !!!