Today we completed a returning visit to replace the solenoid valve for the humidifier and to replace the ultra violet bulb of the air purifier. Today we swapped out both components and ensured they were operating properly. During the replacement of the solenoid valve we noticed that the expansion tank for one of the water heaters had completely failed and the other was acting odd. We recommend having one of our plumbers come out and look over the plumbing system. Humidifier and air purifier are operating properly at this time.