oil tank

Ok here we go, My Trane is derailing and I’m not sure what is going on. It starts out when the t-stat calls for heat, it will light normally. It will run fine for awhile, about 5-10 minutes, then the fire and the circulating fan will stop and the exhaust fan will continue to run. Mind you the temp in the house is still not at the required level. After a few minutes, the unit will attempt to relight the fire. It will go thru the normal 3 attempt cycles and then blow cold air. While the unit is attempting to fire everything in the start up sequence seems to be fine except no gas and of course no fire. The gas valve is getting the required 26 volts while the glow plug is energized, but still no fire. I can leave the unit off for a while, and then turn it back on and it will fire normally and the cycle starts over. Now the heater guy came out and said to have the gas pressure checked by the gas company. He said that the water heater was taking the pressure from the furnace while the water heater was running. I find this hard to believe, so I tested the theory. I had both appliances running at the same time and all was good until the furnace tried to relight and the situation was the same. What will a bad high limit switch do? Or what will a bad or weak compartment temp sensor do? I hope it’s not a bad gas valve, those things are expensive. I'd hate to change it and it not fix anything. Can the gas valve be adjusted? How? What equipment will I need? Thank You for any help you can give.

Hello All, I need to install an oil tank in my house to replace my inground tank. My plan was to install the new tank in my basement,fill it and when the inground tank is empty then I could switch over to the new tank. My first question is about the tank fill pipe and vent pipe. Can someone explain the proper way to do this. Thanks in advance. -quadcells