Answering the question directly, the high temp would be at 180 degrees Fahrenheit.
A few things that could cause slow drying:
- Reduction in make-up air or restrictions in exhaust air due to maintenance needs or physical changes to the facility that are unknowingly restricting air flow (this is the likely culprit)
- A high limit switch activating early
- Gas flow restrictions — valves, tubes, regulators, burners, fan impediments or restrictions
Many times, a thorough maintenance effort is all that is needed to get back up to speed.