Ok I found this rtu to have a bad heat exchanger. I replaced heat exchanger and the roll out tripped. I then replaced the safety and still tripped. I then replaced the inducer and checked gas pressur. all is good on pressure, still trip roll out. I then went and sealed all the edges around the plate of heat exchanger, inducer and any holes I found. Still tripping roll out. any ideas on what else to do. I also drill holes in bottom of cover to allow mor fresh air in.