Arrived on site to perform diagnostic on 8 year old system. Homeowner states that his system is not kicking on at all. It turned on for a bit and then shut off and hasn’t turned on since. Cycled for cooling. Unit is unresponsive. Went into attic to check unit electrical and components. Circuit board is throwing error code for open limit switch. Homeowner recalls trying to run system for heat. Filter is extremely dirty and caused unit to go into lockout mode. Reset furnace. Replaced dirty filter. Cycled for cooling and unit kicked on and started cooling. Performed full evaluation of system. Secondary motor control for compressor has fallen out of allowed budget. Also found unit slightly low on refrigerant. Went over findings and recommendations. With homeowner approval replaced secondary motor control. Also charged unit back up to proper operating pressures with 1lb of R410A. Because unit was only slightly low, it is possible unit could have a leak, or it was never charged correctly