Bosch SST150-40 Installation And Operating Manual page 15

Do not place a valve between the combination temperature
and pressure relief valve and the tank.
Determine T&P relief valve size by the following
specifications, unless they conflict with local codes:
- SST150-40 - 3/4" NPT with a minimum AGA Rating of
105,000 Btu/hr.
- SST250-65/300-80/450-119 - 3/4" NPT with a
minimum AGA Rating of 200,000 Btu/hr.
NOTICE
The SST series water heaters will absorb/store less
than 200,000 Btu/hr when domestic water outlet
temperature is 210°F and boiler water supply
temperature is 240°F. Listed outputs are based on
ASME Section VIII Interpretation VIII-1-86-136. Check
with local codes for applicability.
Minimum Relief Valve (AGA Rating)
Model
SST150-40
SST250-65
SST300-80
SST450-119
Indirect Fired Water Heaters Installation and Operating Manual
Standard Installation
• Install the T&P relief valve in the connection marked
T&P Relief Valve Discharge Piping
T&P relief valve discharge piping must be:
T&P relief valve discharge piping must not be:
Table 4A
BTU/hr
105,000
200,000
200,000
200,000
Installation & Operating Manual
"Relief Valve".
- made of material serviceable for a temperature of
250°F or greater.
- directed so that hot water flows away from all persons.
- directed to a suitable place for disposal.
- installed so as to allow complete draining of the T&P
relief valve and discharge line.
- terminated within 6" of the floor.
- excessively long. Using more than two (2) elbows or 15
feet of piping can reduce discharge capacity.
- directly connected to a drain. Refer to local codes.
- subject to freezing.
WARNING
Do not install any valve between the T&P relief valve
and the tank connection or on the T&P relief valve
discharge piping. Improper placement and piping of
T&P relief valve can cause severe personal injury,
death or substantial property damage.
CAUTION
The T&P relief valve is not intended for constant duty,
such as relief of pressure due to repeated normal
system expansion. Correct this condition by installing
a properly sized expansion tank in a domestic water
system. Refer to the expansion tank manufacturer's
installation instructions for proper sizing.
WARNING
Failure to install and maintain a new, listed ¾" X ¾"
temperature and pressure relief valve will release
the manufacturer from any claim which might result
from excessive temperature and pressures.
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