Arrived on site to replace flame sensor. Upon arrival spoke over with client and showed me system. He stated ever since he got the AC and the sensi thermostat installed furnace is unable to heat home or stay operating. Cycled heat and flame would turn on but would shut off in about 4 to 5 seconds. Replaced flame with a new one and cycled system. System is not sensing the flame. Checked for voltage and all connections are good and secured and they are good. System still not operational. Advised client system is still not working there could be something else going on. Possibility of a bad control board. Advised him we will have another tech come out and look over everything in system. Will not be charging client for part or Visit. Office will call client to get him back on schedule as soon as possible. System still not operating in heating.