DCM11 need to return. Office closed before we could complete maintenance( System #11 ). Need to install (1) F18201 in system #10. Systems 1-10 and 12-13 are completed. System #9s supplemental heat strip sequencer is faulty, tested system to confirm fault, heat sequencers’s internal thermo-disc is beginning to fail, at times it works at times it doesn’t the longer the heat sequencer is energized the more likely it is to fail, recommend replacing heat sequencer to maximize available BTUs at all times. (The heat sequencer required is the same heat sequencer we replaced on 20 dec 2022 in unit #7)