Venting; Thermometers (Not Supplied); Relief Valve - A.O. Smith BT- 80 Installation & Operating Instructions Manual

VENT CONNECTION
Vent connections must be made to an adequate stack or chimney.
Size and install proper size vent pipe. Do not reduce pipe size to
less than that of the draft hood outlet.
Horizontal runs of vent pipe must have a minimum upward slope
toward the chimney of 1/4 inch per foot. Dampers or other
obstructions must not be installed in between the heater and the
draft hood. Be sure that the vent pipe does not extend beyond the
inside wall of the chimney.
Where a continuous or intermittent back draft is found to exist, the
cause must be determined and corrected. A special vent cap may
be required. If the back draft cannot be corrected by the normal
methods or if a suitable draft cannot be obtained, a blower type flue
gas exhauster must be employed to assure proper venting and
correct combustion.

THERMOMETERS (Not Supplied)

Thermometers should be obtained and field installed as shown,
see Figure 4.
Thermometers are installed in the system as a means of detecting
the temperature of the outlet water supply.

RELIEF VALVE

This water heater is equipped with a combination temperature-
pressure relief valve that complies with the standard for relief valves
for hot water supply system, ANSI Z21.22/CSA 4.4. FOR SAFE
OPERATION OF THE WATER HEATER, THE RELIEF VALVE(S)
MUST NOT BE REMOVED OR PLUGGED.
ASME ratings cover pressure relief capacities. ANSI ratings cover
release rate with temperature actuation.
In addition to the appliance relief valve, each remote storage tank
which may be used in conjunction with this appliance shall also be
MIXING VALVE APPLICATION
FOR TWO TEMPERATURE WATER
CIRCULATING RETURN LINE CONNECTIONS
TEMPERED WATER LOOP, IF USED, CONNECT TO POINT
"A". STORED TEMPERATURE WATER LOOP, IF USED,
CONNECT TO COLD WATER INLET.
CAUTION: IF BUILDING COLD WATER SUPPLY HAS A BACK-
FLOW PREVENTER, CHECK VALVE OR WATER METER
WITH CHECK VALVE, PROVISIONS FOR THERMAL
EXPANSION OF WATER IN THE HOT WATER SYSTEM MUST
BE PROVIDED.
installed with a properly sized, rated and approved combination
temperature (ANSI) and pressure (ASME) relief valve(s).
THE PURPOSE OF RELIEF VALVE IS TO AVOID EXCESSIVE
PRESSURE OR TEMPERATURE INTO THE STEAM RANGE,
WHICH MAY CAUSE SCALDING AT FIXTURES, TANK
EXPLOSION, SYSTEM OR HEATER DAMAGE. NO VALVE IS TO
BE PLACED BETWEEN THE RELIEF VALVE AND TANK.
Your local code authority may have other specific relief valve
requirements.
A DRAIN LINE MUST BE CONNECTED TO THE RELIEF VALVE
TO DIRECT DISCHARGE TO A SAFE LOCATION TO AVOID
SCALDING OR WATER DAMAGE. THIS LINE MUST NOT BE
REDUCED FROM THE SIZE OF THE VALVE OUTLET AND MUST
NOT CONTAIN VALVES, RESTRICTIONS NOR SHOULD IT BE
LOCATED IN FREEZING AREAS. DO NOT THREAD OR CAP THE
END OF THIS LINE. RESTRICTED OR BLOCKED DISCHARGE
WILL DEFEAT THE PURPOSE OF THE VALVE AND IS UNSAFE.
DISCHARGE LINE SHALL BE INSTALLED TO ALLOW COMPLETE
DRAINAGE OF BOTH THE VALVE AND LINE.
See SERVICE INFORMATION section for procedure and
precautions.
The type, size and location of the relief valves must be in accordance
with local codes. The locations of the relief valves shown in the
installation diagrams are typical. The heater has a factory installed
high temperature limit switch.
For circulating heaters, the separate storage vessel must have a
temperature and pressure relief valve installed. This valve shall
comply with the standard for relief valves and automatic gas shutoff
devices for hot water supply systems.
Cold water inlet lines to heater should be installed as shown in
order to minimize gravity circulation of hot water to building cold
water lines.
SINGLE TEMPERATURE
TEMPERATURE SETTING SHOULD NOT EXCEED SAFE
USE
TEMPERATURE REGULATION ON PAGE 12. IF HIGHER
PREHEAT TEMPERATURES ARE NECESSARY TO
OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-
SCALD VALVE FOR HOT WATER SUPPLIED TO
FIXTURES.
FIGURE 4
7
WARNING
INSERT B - VACUUM
RELIEF VALVE
*INSTALL PER
LOCAL CODES
INSTALL THERMAL EXPANSION
TANK OR DEVICE IF CHECK VALVE
OR PRESSURE REDUCING
VALVE IS USED IN SUPPLY
WARNING
TEMPERATURE AT FIXTURES, SEE