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SDT/SET Installation & Operation Manual
14
NOTICE
Verify that the combination
temperature and pressure relief valve
complies with local codes. If the
combination temperature and pressure
relief valve does not comply with local
codes, replace it with one that does.
Follow the installation instructions in
this section.
NOTICE
The Lochinvar SDT/SET 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.
Standard Installation
• Install the T&P relief valve in the connection marked
“Relief Valve”.
T&P Relief Valve Discharge Piping
T&P relief valve discharge piping must be:
- 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.
T&P relief valve discharge piping must not
be:
- 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.
ƽ 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.
ƽ 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.
Do not place a valve between the combination temperature
and pressure relief valve and the tank.
ƽ WARNING
Failure to install and maintain a new, listed
3/4" X 3/4" temperature and pressure relief
valve will release the manufacturer from any
claim which might result from excessive
temperature and pressures.
Determine T&P relief valve size by the following
specifications, unless they conflict with local codes:
- SDT/SET065/080/119 - 3/4" NPT with a
minimum CSA Rating of 200,000 Btu/hr.
Table 4A
Minimum Relief Valve (CSA Rating)
Model BTU/hr
SDT/SET065 200,000
SDT/SET080 200,000
SDT/SET119 200,000
4 Domestic Side (Tank) Piping