Installation and service must be performed by a qualified plumber. In the
10. Water Piping Commonwealth of Massachusetts, this product must be installed by a licensed plumber or gas fitter in accordance with the Massachusetts Plumbing and Fuel Gas Code 248 CMR Sections 2.00 and 5.00. Observe all applicable codes.
This appliance suitable for potable water and space heating applications. Do not use this appliance if any part has been underwater. Immediately call a qualified service technician to inspect the appliance and replace any part of the control system and gas control which has been under water.
If the water heater is installed in a closed water supply system, such as one having a backflow preventer in the cold water supply line, means shall be provided to control thermal expansion. Contact the water supplier or a local plumb- ing inspector on how to control this situation.
A pressure relief valve must be installed near the hot water outlet that is rated in accordance with and complying with either The Standard for Relief Valves and Automatic Shutoff Devices for Hot Water Supply Systems, ANSI Z21.22, or The ANSI/ASME Boiler and Pressure Vessel Code, Section IV ( Heating Boilers ). This pressure relief valve must be capable of an hourly Btu rated temperature steam discharge of 199,900 Btuh. Multiple valves may be used. The pressure relief capacity must not exceed 150 psig. No valve shall be placed between the relief valve and the water heater. The relief valve must be installed such that the discharge will be conducted to a suitable place for disposal when relief occurs. No reducing coupling or other restriction may be installed in the discharge line. The discharge line must be installed to allow complete drainage of both the valve and the line. If this unit is installed with a separate storage vessel, the separate vessel must have its own temperature and pressure relief valve. This valve must also comply with The Standard for Relief Valves and Automatic Gas Shutoff Devices for Hot Water Supply Systems, ANSI Z21.22. (in the U.S. only). A temperature relief valve is not required, but if one is used, do not install the valve with the probe directly in the flow of water. This may cause unwarranted discharge of the valve.
Piping and components connected to the water heater shall be suitable for use with potable water. Toxic chemicals, such as those used for boiler treatment, shall not be introduced into the potable water.
A water heater used to supply potable water may not be connected to any heating system or components previously used with a nonpotable water heating appliance.
When water is required in one part of the system at a higher temperature than in the rest of the system, means such as a mixing valve shall be installed to temper the water to reduce the scald hazard.
•Flush water through the pipe to clean out metal powder, sand and dirt before connecting it.
•Take appropriate heat insulation measures (e.g., wrapping with heat insulation materials, using electric heaters) according to the climate of the region to prevent the pipe from freezing.
•Use a union coupling or flexible pipe for connecting the pipes to reduce the force applied to the piping.
•Do not use piping with a diameter smaller than the coupling.
•When feed water pressure is too high, insert a depressurizing valve, or take water hammer prevention measure.
•Avoid using joints as much as possible to keep the piping simple.
•Avoid piping in which an air holdup can occur.
•If installing the unit on a roof:
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If the unit is installed on a roof to supply water to the levels below, make sure that the water pressure supplied to the unit does not drop below 29 psi. It may be necessary to install a pump system to ensure that the water pressure is maintained at this level.
Check the pressure before putting the unit into operation.
Failure to supply the proper pressure to the unit may result in noisy operation, shorter lifetime of the unit, and may cause the unit to shut down frequently.
Supply water piping
•Do not use PVC, iron, or any piping which has been treated with chromates, boiler seal or other chemicals.
•Mount a check valve and a shut off valve (near the inlet).
•In order for the client to use the water heater comfortably, 98.1 to 491 kPa (14 to 70 PSI) of pressure is needed from the water supply.
Be sure to check the water pressure. If the water pressure is low, the water heater cannot perform to its full capability, and may become a source of trouble for the client.
Drain piping
•Expansion water may drop from the pressure prevention device and wet the floor. If neces- sary, provide drain piping or use a drain hose to remove the water.
Hot water piping
•Do not use lead, PVC, iron or any piping which has been treated with chromates, boiler seal or other chemicals.
•The longer the piping, the greater the heat loss. Try to make the piping as short as possible.
•Use mixing valves with low water resistance. Use shower heads with low pressure loss.
•If necessary, use a pump or other means to en- sure that the supply water pressure to the inlet of the heater does not fall below 29 PSI when the maximum amount of water is being demanded. Also install a pressure meter on the inlet. If this is not done, local boiling will occur inside the water heater causing abnormal sounds and decreasing the durability of the heat exchanger.
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