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Installation and Operating Instructions
5.3.1 Closed System /Thermal Expansion
NOTICE
Product damage, property damage!
•
Do not install a check valve or other back flow device that creates a closed
system unless required by code. A closed system may result in frequent
discharge due to thermal expansion from the pressure relief valve.
Periodic discharge of the temperature and pressure relief valve may be due to
thermal expansion in a closed water supply system. The water utility supply meter
may contain a check valve, backflow preventer or water pressure reducing valve.
This will create a closed water system. During the heating cycle of the water
heater, the water expands causing increased pressure inside the water heater.
The temperature and pressure relief valve may discharge hot water under these
conditions which results in water escaping from the valve and a build-up of lime on
the relief valve seat. To prevent this from happening, it is recommended to:
•
Install a diaphragm-type expansion tank that is suitable for potable water
on the cold water supply line. The expansion tank must have a minimum
capacity of 1.5 US gallons for every 50 gallons of stored water.
5.3.2 Relief Valves
WARNING
Personal injury, property damage!
•
The pressure rating of the relief valve must not exceed 150 PSI, and not
exceed the maximum working pressure of the water heater as marked on
the rating plate.
WARNING
Personal injury, property damage!
•
Failure to maintain a listed, adequately sized temperature & pressure
relief valve will release the manufacturer from any claim which might
result from excessive temperatures and pressures.
This water heater comes equipped with a temperature & pressure relief (T&P) valve
with a pressure rating of 150 PSI. Provide tubing so that it terminates not more
than 6 inches (152 mm) above and not less than two times the discharge pipe
diameter above the floor or flood level rim of the waste receptor,or as required by
local code, and does not contact any live electrical part. The discharge opening
must not be blocked or reduced in size under any circumstances.
Your local jurisdictional authority, while mandating the use of a temperature-
pressure relief valve complying with ANSI Z2 I .22•CSA 4.4 and ASME, may require
a valve model different from the one furnished with the water heater.
Compliance with such local requirements must be satisfied by the installer or end
user of the water heater with a locally prescribed temperature-pressure relief valve
installed in the designated opening on the water heater in place of the factory
furnished valve.
For safe operation of the water heater, the relief valve must not be removed from its
designated opening or plugged.
Piping used should be of a type approved for hot water distribution. The discharge
line must be no smaller than the outlet of the valve and must pitch downward from
the valve to allow complete drainage (by gravity) of the relief valve and discharge
line. The end of the discharge line should not be threaded or concealed and should
be protected from freezing. No valve of any type, restriction or reducer coupling
should be installed in the discharge line.
Excessive length, over 30 feet, or use of more than four elbows can cause
restriction and reduce the discharge capacity of the valve.
12 |
The temperature & pressure relief valve:
•
Must not be in contact with any electrical part
•
Must be connected to a proper discharge line which terminates at an
adequate drain
•
Must not exceed the working pressure shown on the data plate of the
water heater
•
Must be of materials listed for hot water distribution
Discharge Line
WARNING
Scald hazard, property damage!
•
Discharging water may be hot and can cause scald injuries and property
damage. Discharge lines must be properly installed and piped to an
adequate drain.
The discharge line:
•
Must not be smaller than the pipe size of the relief valve
•
Must not be capped, blocked, plugged or contain any valve between the
relief valve and the end of the discharge line
•
Must terminate 6 inches above a floor drain or external to the building
•
Must be capable of withstanding 250°F (121°C) without distortion
•
Must be installed to allow complete drainage of both the temperature and
pressure relief valve and discharge line
Relief
Valve
Discharge
Line
6"
Maximum
Relief valve installation
Figure 3
Bosch GreenTronic 7000 T Hybrid Electric Water Heater - BTC 755003301 A (03.2024)
Floor Drain
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