Ignition control had a 4 flash for limit switch lockout. Tech found manually resettable rollout switch tripped. Reset switch and burners lit. Adjusted LP gas pressure from 11.1” WC to 10.0” WC. Checked heat exchanger. Found rust, but no cracks or holes. Tech allowed heat to run with panel closed for 10 minutes continuously. Rollout did not trip again. Customer also had questions about Wi-Fi message on tstat. Tech answered her questions. Wi-Fi is optional. Tech helped customer set up No charge for callback to adjust gas pressure. Customer’s daughter will try in a few days to create a Honeywell account. Tstat is already connected to Wi-Fi. Just needs to add CRC and MAC ID to add device.