Performed the heating maintenance on four systems. Upstairs unit has an over amping gas valve. Kitchen unit has a crack in the heat exchanger and that system is too be replaced. No issues with the other two systems. System to be replaced is located to the left of the entry door of the main house and the condensing unit is to the left coming down the driveway next to the propane tank. Replace the office thermostat for free with customer supplied thermostat.