A.O. Smith Hot Water Generator Technisches Handbuch

InstallatIon

requIred aBIlIty

Installation or service of this hot water generator requires ability

equivalent to that of a licensed tradesman in the field involved pipe

fitting in the steam or boiler water is required. See Qualified Installer

or Service Agency on page 2.

teMperature-pressure relIef ValVe

This water heater is provided with a properly rated/sized and certified

combination temperature - pressure relief valve by the manufacturer.

The valve is certified by a nationally recognized testing laboratory

that maintains periodic inspection of production of listed equipment of

materials as meeting the requirements for Relief Valves for Hot Water

Supply Systems, ANSI Z21.22 • CSA 4.4, and the code requirements

of ASME.

If replaced, the new valve must meet the requirements of local codes,

but not less than a combination temperature and pressure relief

valve rated/sized and certified as indicated in the above paragraph.

The new valve must be marked with a maximum set pressure not to

exceed the marked hydrostatic working pressure of the water heater

(150 psi = 1,035 kPa) and a discharge capacity not less than the

water heater Btu/hr or KW input rate as shown on the water heater’s

model rating plate.

For safe operation of the water heater, the temperature and pressure

relief valve must not be removed from its designated opening nor

plugged. The temperature-pressure relief valve must be installed

directly into the fitting of the water heater designed for the relief valve.

Install discharge piping so that any discharge will exit only within 6

inches (15.2 cm) above, or at any distance below the structural floor.

Be certain that no contact is made with any live electrical part. The

discharge opening must not be blocked or reduced in size under

any circumstances. Excessive length, over 30 feet (9.14 m), or

use of more than four elbows can cause restriction and reduce the

discharge capacity of the valve.

No valve or other obstruction is to be placed between the relief valve

and the tank. Do not connect discharge piping directly to the drain

unless a 6” (15.2 cm) air gap is provided. To prevent bodily injury,

hazard to life, or property damage, the relief valve must be allowed

to discharge water in adequate quantities should circumstances

demand. If the discharge pipe is not connected to a drain or other

suitable means, the water flow may cause property damage.

The Discharge Pipe:

•

Shall not be smaller in size than the outlet pipe size of the valve,

or have any reducing couplings or other restrictions.

•

Shall not be plugged or blocked.

•

Shall be of material listed for hot water distribution.

•

Shall be installed so as to allow complete drainage of both the

temperature-pressure relief valve and the discharge pipe.

•

Must terminate a maximum of six inches above a floor drain or

external to the building. In cold climates, it is recommended that

the discharge pipe be terminated at an adequate drain inside

the building.

•

Shall not have any valve or other obstruction between the relief

valve and the drain.

The temperature-pressure relief valve must be manually operated

at least once a year. Caution should be taken to ensure that (1) no

one is in front of or around the outlet of the temperature-pressure

relief valve discharge line, and (2) the water manually discharged

will not cause any bodily injury or property damage because the

water may be extremely hot. If after manually operating the valve, it

fails to completely reset and continues to release water, immediately

close the cold water inlet to the water heater, follow the draining

instructions in this manual, and replace the temperature-pressure

relief valve with a properly rated/sized new one.

If you do not understand these instructions or have any questions

regarding the temperature-pressure relief valve call the toll free

number listed on the back cover of this manual for technical

assistance.

closed water systeMs

Water supply systems may, because of code requirements or such

conditions as high line pressure, among others, have installed

devices such as pressure reducing valves, check valves, and back

flow preventers. Devices such as these cause the water system to

be a closed system.