Installation Manual

H-Series Demand Duo™ 2 Installation and Operation Manual 30
• A licensed professional must install the gas supply.
• Turn off 120V power supply.
• Turn off the gas.
• Gas is flammable. Do not smoke or provide other ignition sources while working with gas.
• Do not turn on the water heater or gas until all fumes are gone.
WARNING
1. Install a manual gas control valve in the gas supply line to the water heater. A union can be used on the
connection above the shut off valve for the future servicing or disconnection of the water heater (see
image to right).
2. Check the type of gas and gas supply pressure before connecting the water heater. If the water heater is
not of the gas type that the building is supplied with, DO NOT connect the water heater. Contact the
dealer for the proper water heater to match the gas type.
3. Check the gas supply pressure immediately upstream at a location provided by the gas company.
Supplied gas pressure must be within the limits shown in the Specifications section of this manual with
all gas appliances operating.
4. Before placing the appliance in operation, all joints, including the water heater, must be checked for gas
tightness by means of soap, gas leak detector solution, or an equivalent nonflammable solution, as
applicable. Since some leak test solutions, including soap and water, may cause corrosion or stress
cracking, rinse the piping with water after testing, unless it has been determined that the leak test
solution is non-corrosive.
5. Use approved connectors to connect the water heater to the gas line. Purge the gas line of any debris
before connection to the water heater.
6. Any compound used on the threaded joint of the gas piping must be chemically compatible and
mechanically suitable to be used in liquefied petroleum gas (LPG/Propane) applications.
7. The gas supply line shall be gas tight, sized, and installed to provide a supply of gas sufficient to meet
the maximum demand of the water heater and all other gas-consuming appliances at the location
without loss of pressure. If in doubt about the size of the gas line, refer to the Installation and Operation
Manual for Commercial CU199 Condensing Tankless Water Heaters.
8. Perform a leak and pressure test prior to operating the water heater. If a leak is detected, do not operate
the water heater until the leak is repaired.
To connect the gas supply:
Gas
Valve
Union
Union
Gas
Valve