Specifications
Element/Electrical Data
Warranty Information
Installation with Heat Pumps
Solar Applications
High Temp. Applications
Parts Listings
Trouble Shooting Guide
Tank Draining
Tank Cleaning
Testing Electric Components
Thermal Expansion





Recommendations for
High Volume/High Temperature Marathon Water Heater Applications

Agricultural, Commercial and Multifamily applications place special demands on a water heater. However, there are a number of steps you can take to extend the service life of your equipment.

  • Don't undersize. You will not be saving any money by going to a tank smaller than you need. Your demand typically requires a given volume of hot water. It takes the same number of btu's to heat it whether it is in a 50-gallon tank or 105-gallon tank. The difference is that the 105-gallon tank will provide reserve and won't be running at the outer limits of its capabilities.

  • Set it up right: The Marathon's thermostat is designed with an upper limit of 170F. The BOTTOM thermostat is adjustable to this temperature, which means the entire tank can be heated to this level. On tanks made after 5/03, the TOP thermostat was changed to have a maximum setting of 160F for safety reasons. If you would like a high temperature top thermostat, order "Special Use/Dairy Thermostat" Part number SP313070. Always set your bottom thermostat higher than your top in elevated temperature applications.

  • Reduce element wattage. As you lower the wattage of an element, the thermal stress that is placed on it is reduced. In addition, lowering the surface temperature reduces the build up of minerals to some degree.

  • Replace the boiler drain with a full port ball valve. The ¾" boiler drain on the heater actually gets reduced to about 3⁄8" inside of the valve. High volume applications will naturally accumulate a much greater volume amount of sediment. Replacing the valve with a 2" brass nipple and ¾" full port ball valve (these remain ¾" throughout the body) will allow you to open the valve quickly and blow out any sediment in a matter of a minute or less. Leave the water pressure on and clean out the tank monthly. A hose adapter can easily be added to the valve if it is necessary to add a garden hose.

  • Do a water test. There are a number of companies that will test your water for a nominal fee. Knowing your hardness, ph, dissolved solids, and mineral content will give you a much better idea of what you are dealing with and how to mitigate it. Water conditioners, water filters, phosphate feeders are all options that may be effective in prolonging the equipment in your facility.

  • Use the lowest water temperature allowable. Most applications require specific water temperatures that must be met. Be sure to meet these, but avoid setting the water heater at temperatures in excess of this. It not only wastes energy, but also increases the calcium build up and shortens element life.

  • Check your electric service. Most think that if they have 220volt power they are good to go. Did you know that a bad ground can cause element failure? Agricultural applications are notorious for poor grounds at the service entrance and at each equipment contact point. This results in stray voltage, which affects the herd and directly impacts the operation of your water heater. If you are experiencing element or thermostat issues, check to make sure you have a continuous ground from the tank all the way to the ground rod (better yet, check it during installation!).