Temperature And Pressure Relief Valve - American Standard ULN 75-76 Operating, Installation And Service Manual

INSTALLATION (Using Top Connect Only)
Typical installation showing two (2) Commercial Heaters in parallel manifold using top connect only.
Typical installation showing three (3) Commercial Heaters in parallel manifold using top connect only.
Typical installation showing four (4) Commercial Heaters in parallel manifold using top connect only.
WARNING
Hydrogen gas can be produced in a hot water system that has not been used for a long period of time (generally two weeks or more).
HYDROGEN GAS IS EXTREMELY FLAMMABLE. To prevent the possibility of injury under these conditions, we recommend the hot
water faucet be opened for several minutes at the kitchen sink before you use any electrical appliance which is connected to the hot water system.
Do not light a cigarette, cigar or pipe. Do not smoke. If hydrogen is present, there will probably be an unusual sound such as air escaping through
the faucet as the water begins to flow. Remember, no smoking or open flame near the faucet at the time it is opened.
15

TEMPERATURE AND PRESSURE RELIEF VALVE

For protection against excessive pressures and/or temperatures, a temperature and pressure relief valve must be installed in the opening marked
"temperature and pressure relief valve". A design 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 Shut-off devices for Hot Water Supply
Systems, ANSI Z21 .22. Pressure rating of the valve must not exceed the working pressure shown on the rating plate of the water heater. Relief
piping must terminate 6 inches above a floor drain or external to the building. Do not thread, cap, or plug the end of this discharge line. Be certain
that no contact is made with any live electrical part. Do not connect discharge line directly to drain. (Figure 5)
To prevent bodily injury, hazard to life or damage to property, the relief valve must be allowed to discharge water in the event of excessive
temperature or pressure developing in the water heater. The function of the temperature and pressure relief valve is to discharge water in large
quantities should circumstances demand. If the discharge pipe is not directed to a drain as shown in Figure 5, or other suitable means, the water flow
may cause property damage.
The discharge line:
(1) Must not be smaller than the pipe size of the relief valve,
(2) Must not be plugged or blocked,
(3) Must be of material capable of withstanding 210°F without distortion,
(4) Must be installed so as to allow complete drainage of both the temperature
and pressure relief valve and discharge line,
(5) Must terminate at an adequate drain (Figure 5)
(6) Must not have any valve between the relief valve and the end of the discharge line.
Failure to install and maintain a new properly listed temperature and pressure
relief valve will release the manufacturer from any claim which might result from
excessive temperature or water pressure.
Figure 10
WARNING
Do not attempt to operate this water heater with the cold water inlet valve closed. Manually operate the pressure-temperature relief
valve at least once a year. To prevent water damage, discharge line must terminate at an adequate drain. Standing clear of the outlet
(discharge water may be hot), lift and release the lever handle on the pressure-temperature relief valve to make the valve operate
freely.
If the temperature and pressure relief valve on the appliance discharges periodically, this may be due to thermal expansion in a closed
water supply system (see "Pressure Build-Up in Water System" -Page 1). Contact the water supplier or local plumbing inspector on
how to correct this situation. Do not plug the temperature and pressure relief valve.
TEMPERATURE
AND PRESSURE
RELIEF VALVE
MANUAL RELIEF
LEVER
DISCHARGE LINE TO DRAIN
Figure 11
16