Disassembled and reinstalled water heater burner assembly. Original installation company had replaced the assembly incorrectly causing flames to travel below the burner plate and around the combustion chamber. Assembly was also caked in soot which was cleaned off. I also prepared and emailed an estimate to repipe the thermal expansion tank piping as in its current location, before the check valve it is not serving any purpose. Water pressure rose to over 140psi while heater was on.