Rheem XR90 Series Use and Care Manual - Page 18

Supplemental instructions for gas water heaters installed in potable water/space heating applications. Local codes or plumbing authority requirements may vary from the instructions or diagrams provided in this manual and take precedent over these instructions. Hot water supply to house Hot water supply to heating unit From HOT outlet on water heater Tee fitting for vertical hot water supply lines. Hot water supply to house From HOT outlet on water heater Hot water supply to heating unit Combination Potable Water and Space Heating Application Tee fitting must be installed as shown. This ensures that any air in the water lines will be purged through the domestic water faucets and showers. DANGER: When this system requires water for space heating at elevated temperatures (above 125°F [52°C.]), a mixing or tempering valve must be installed in the hot water supply line to the house in order to reduce the scald hazard potential. DANGER: Any piping or components used in the installation of this water heater in a combination potable and space heating application must be suitable for use with drinking water. DANGER: If this water heater is installed in an application intended to supply domestic hot water needs and hot water for space heating purposes, do not connect the heater to an existing heating unit or components of a heating system that have previously been used with a non drinking water system. Toxic chemicals such as those used for boiler treatment may be present and will contaminate the drinking water supply causing possible health risks. Never introduce toxic chemicals, such as those used for boiler treatment, into this system. Notice: 50' - 0" maximum distance from water heater to fan coil (developed length) is required for Massachusetts State. Tee fitting for horizontal hot water supply lines. Typical Piping Diagram for Combination Potable/Space Heating Installation Pressure Gauge Nominal 3/4" size mixing or tempering valve (refer to warning above). Follow mixing or tempering valve manufacturer's instructions for installation of the valve. Minimum of 2'-0" developed length of 3/4" pipe. Air vent 3/4" Tempered domestic hot water supply to house. 3/4" Check Valve with 1/8" Hole 3/4" Shut-Off Valve (Typ.) 3/4" cold water supply Spring loaded check valve in heating unit hot water supply line and cold water return line (not supplied with water heater) NOTE: This check valve is incorporated in some heating units. Refer to the installation instructions supplied with specific heating unit to determine if it is required. Isolation valve in hot water supply line to heating unit (not supplied with water heater) 3/4" ShutOff Valve (Typ.) 3/4" Shut-Off Valve (Typ.) Heat Trap 6" Min. 2 Gallon Thermal Expansion Tank (if required-not supplied with water heater) See diagrams above for proper pipe application for vertical or horizontal supply lines. Temperature and Pressure Relief Valve, tie to location approved by local code 140° 120° to 130° Hot water to space heater Hot water coil All bronze pump. Check valve internal in pump. Air bleed valve. Water Sample Tap. Gas line to water heater Temperature and pressure relief valve discharge line Gas Control (Thermostat) Gas Fired Water Heater Water Heater drain pan installed in accordance with the Local and State Code Water Heater to be installed in accordance with the Local and State Energy Code All water piping shall be insulated in accordance with Local and State Energy Code. 18 3/4" HWS & HWR to Heating Coil. Drain valve (not supplied with water heater) Isolation valve in cold water return line from heating unit (not supplied with water heater) Gas Direct Vent discharge must comply with Local and State Codes Combustion Air Inlet Openings Vacuum Relief Valve (Not Supplied) 6" Air Gap If required, install per local codes and valve manufacturer's instructions. Air Handler To HVAC Unit. T FAN ON OFF HEAT COOL Electronically controlled pump timer. Activates every 6 hours for 60 seconds. Wire to bronze pump.