Installing a Marathon water heater by Rheem involves connecting the electricity and water supply as well as assembling the heater. Rheem Marathon water heaters come in more than one model, and specifics of installation vary accordingly.
As of 2015, assembly of the standard residential Marathon water heater only requires attaching the drain pan at the bottom. The drain pan is only necessary in areas that might be damaged by water leakage. The heater also requires connecting the pan to an open drain.
Installers should use flexible copper connectors to connect the hot and cold water pipes. The hot water heater needs to be connected to a source of cold water. The hot water outlet is connected to the house's water system. Once these connections are made, installers close the drain valve. They then open the shut off valve from the cold water supply line and open the hot water faucet in each sink to allow air to vent. When water has filled the heater, hot water comes from the sinks, so the faucets can be shut off.
An electrician must supply a separate branch circuit with copper conductors for the water heater. Branch circuit wiring should also include a metallic conduit and a non-metallic sheathed cable. Both ground the electricity to the appliance. Voltage requirements and wattage load vary by model.