Responded to a no cooling call on a Lennox air conditioner installed in 2012. Found that the 30A circuit breaker (correctly sized per the unit's rating plate) had been turned off or tripped. Determined that the client may have accidentally turned off the breaker while testing their in-floor heating system. After restoring power, inspected the outdoor condenser and found the coil heavily clogged with debris. Advised that cleaning was necessary before further testing. Client agreed, and the condenser coil was thoroughly cleaned. After cleaning, tested the system and found a low temperature differential. Attached gauges and confirmed that the system is low on refrigerant. Added leak sealant and UV dye, along with the correct amount of refrigerant. Explained that there is no guarantee the sealant will stop the leak, but if it fails, the UV dye may help identify the source for future repair. At this time, the system is operating normally.