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SECTION II: GENERAL INFORMATION (cont.)
ANODE RODS
The anode rod is used as a sacrificial element within the volume of the storage tank. The
purpose of the magnesium anode rod is to protect the inside of the tank against corrosion.
Anode rods should be inspected twice in the first year and at least yearly once a time interval
for inspection has been developed. Water conditions can influence the consumption rate of
the anode rods. Please see the Maintenance section of this manual for instructions on how to
change the anode rods in your Caleffi water heater.
CAUTION
Hydrogen gas is produced in a hot water system served by the 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.
TEMPERATURE AND PRESSURE RELIEF VALVE (T&P)
CAUTION
To reduce the risk of excessive pressures and temperatures in this water heater, install
temperature and pressure protective equipment required by local codes and no less
than a combination temperature and pressure relief valve 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, ANSI Z21.22. 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 in an opening provided and marked for
this purpose in the water heater, and orient it 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.
The T&P valve is factory installed. A discharge drain tube must be installed (responsibility
of the installer) and shall terminate plain, not threaded, 6 inches above the floor drain.
The drain tube material must be approved for temperatures of 120°F or greater and a
pressure of 150 PSI or greater.
BACKFLOW PREVENTER (CLOSED LOOP SYSTEM)
Some local municipal codes and ordinances require the use of these devices on potable
(domestic) water lines. Where backflow preventers are required, it will be necessary to install
a
thermal expansion tank
(designed for used with potable water) in order to prevent
pressure build up in the indirect heater and associated piping, which could cause the T&P
valve to discharge. Follow the expansion tank manufacturer’s recommendations when
selecting a tank for your hot water system.
Note: Working pressure of the water heater is 150 PSI. Do not exceed 150 PSI.
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Summary of Contents for NAS200 Series
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