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3
Piping
(continued)
Domestic Water Piping for Distant Fixtures
In some cases the furthest fixture may be quite distant from the
tank.
In such an installation the configuration shown in
FIG. 3-5 would result in an unacceptable delay before hot water
reaches these distant fixtures.
relatively close to the tank, the building owner may want hot
water at all fixtures as soon as they are opened.
A solution to this problem is that a pipe runs from the furthest
fixture on each branch back to the return of the tank. A small
bronze circulator is mounted in this line and is wired so as to
run continuously. A check valve in this line permits flow
towards the tank inlet only.
When no fixtures are drawing water, the bronze circulator
moves hot water from the tank to the end of the branch just
below the last fixture, then back to the inlet of the tank via the
return pipe. When a fixture is opened, hot water is already out
in the branch very close to the fixture and hot water appears at
it almost immediately. The check valve prevents cold water in
the tank's inlet pipe from passing around the tank and heading
directly to the fixture.
Because hot water is always circulating in the hot water branch
the entire branch should be insulated to prevent excessive heat
loss.
Temperature & Pressure (T&P) Relief Valve
To reduce the risk of excessive pressures and
CAUTION
temperatures in the water heater, install
temperature
equipment required by local codes, but no
less than a combination temperature and
pressure relief valve certified by a nationally
recognized testing laboratory that maintains
periodic inspections of production of listed
equipment or materials, as meeting the
requirements for Relief Valves and Automatic
Gas Shutoff Devices for Hot Water Supply
Systems, ANSI Z21.22. This valve must be
marked with a maximum working pressure
of the water heater.
•
Every Lochinvar Indirect Water Heater
must be protected with a T&P relief
valve.
•
Determine T&P relief valve size by the
following specifications, unless they
conflict with local codes:
-
-
Even if all the fixtures are
and
pressure
protective
SSS031/041 - 3/4" NPT with an
AGA Rating of 100,000 Btu/hr.
SSS051/081/119 - 3/4" NPT with an
AGA Rating of 200,000 Btu/hr.
Installation & Operation Manual
For proper operation of the T&P and to
NOTICE
prevent the T&P from activating due to
boiler water temperature, use a T&P relief
valve with extended element.
recommended element length is 8 inches.
The Lochinvar SSS series water heaters will
NOTICE
absorb 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 12" 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. Terminate discharge
piping within 6" from drain. Refer to local codes.
- subject to freezing.
Do not install any valve between T&P relief
WARNING
valve and tank connection or on T&P relief
valve discharge piping.
placement and piping of T&P relief valve
can cause severe personal injury, death or
substantial property damage.
T&P relief valve is not intended for
CAUTION
constant duty, such a relief of pressure due
to repeated normal system expansion.
Correct this condition by installing a
properly sized expansion tank in domestic
water system. Refer to expansion tank
manufacturer's installation instructions
for proper sizing.
The
Improper
11
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