In 2004 we had the first Sentry Pool Heaters ever made installed when we had a new aquatic center built. In 2005 we installed the Sentry Pool Heaters at our other aquatic center that we built in 2003 since the original heaters did not work properly. In 2016 we had new Sentry Pool Heaters installed at both of our aquatic centers. Before the pool season starts the condensation plugs are replaced and the pool heaters are turned on once the surge tanks are filled and the Sentry Pool Heaters run themselves. At the end of the summer the heaters are turned off and condensation plugs are removed for the winter. The heaters cycle on and off depending on the temperature of the pool water. We have one pool that is 10,500 sq ft surface area with shallow water (150,000 gallons of water) and even if the air temperature gets down to 55 Degrees at night the pool water is at 78 degrees at 6:00 am when I show up to work. The only maintenance we have done in the three years we have had the new Sentry Pool Heaters is to clean the filter that collects dust from the air intake. These heaters are the one thing I don’t have to worry about when the aquatic Centers are open, they run themselves.