Upon arrival, system was intermittently having combustion vary from first 4 burners to all. When only 4 would ignite, ignition would fail at flame rectification. Gas pressure is within range but there is alot of rust and condensation around gas valve and throughout combustion area. Pulled burners and found corrosion around all burners. Cleaned out to make flame transfer smoother. Cycled system 15x, full combustion occurred across all burners everytime- hesitated on 3rd fire and 12th fire (burner 4to5) but pushed through. If issue occurs again, recommend replacing burner assembly. HSi Is also very close to failure but currently operational. Replaced hsi and purchased membership