Performed preventative maintenance for 3 heating systems. 2 single zone mini split systems and a multi-zone boiler that chud installed in 2020. Inspected all the electrical components. Confirmed proper high and low voltages. Cleaned the washable filters for both mini split systems. Cleaned the burners, flame sensor/spark ignition and burner compartment. Confirmed proper water pressure at 18psi in boiler. Ran system to make sure damper opened and boiler got to set high temperature of 180°. Performed a combustion analysis on the boiler. System is operating at 83.4% efficiency with a CO level of 11ppm. Both mini split systems are Mr. Cool DIY units. They run as they are suppose to but don’t have surge protectors on the disconnect boxes. This runs the risk during storms to fry the control board if a power surge were to happen. I’ve seen it happen on other systems. The heat pump coil near the kitchen is fairly dirty due to being close to the dryer vent. Recommend chemical coil cleaning to p