7.Appendix
32
7.5.The method of grounding
Picture 10
7.6.Installation of a P&T valve
is used to prevent the temperature or pressure becoming too high inside the tank. When
the temperature or pressure reaches the set value, the valve will open automatically so as to force the
pressure or temperature to decrease.
The handle of the safety valve should be tested once every six months so as to remove the calcium
carbonate deposits and guarantee there is no blockage in the device. Take care to avoid burns for the
temperature of the discharging water is very high.
Vent pipes should be thermally insulated to prevent safety risks caused by freezing pipes in winter.
P&T valve
31
7.Appendix
7.4.CAUTION-1
To reduce the risk of excessive pressures and temperatures in this water heater, install
temperature and pressure protective equipment required by local codes. A combination
temperature and pressure relief valve must be certified by a nationally recognized testing
laboratory that maintains periodic inspection of production of listed equipment or materials, as
meeting the requirements for Relief Valves and Automatic Gas Shutoff Devices for Hot Water
Supply Systems, AS1357.1. This valve must be marked with a maximum set pressure not to
exceed the marked maximum working pressure of the water heater. Install the valve into an
opening provided and marked for this purpose in the water heater. Install the P&T Valve or
provide tubing so that any discharge from the valve exits only within 6 Inches above, or at any
distance below, the structural floor, and does not contact any live electrical part. The discharge
opening must not be blocked or reduced in size under any circumstances.
Hydrogen gas is produced in a hot water system served by this heater that has not been
used for a long period of time (2 weeks or more). Hydrogen gas is extremely flammable. To
reduce the risk of injury under these conditions, it is recommended that the hot water faucet
be opened for several minutes at the kitchen sink before using any electrical appliance
connected to the hot water system. When hydrogen is present, there will probably be an
unusual sound such as air escaping through the pipe as the water begins to flow.
There should be no smoking or open flame near the faucet at the time it is open.
CAUTION-2
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