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.
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.
Do not place a valve between the combination temperature
and pressure relief valve and the tank.
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
