Installation & Operation Manual
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.
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.
NOTICE
NOTICE
For proper operation of the T&P and to prevent the T&P from activating due to boiler water temperature, use a T&P relief
valve with extended element. The recommended element length is 8 inches.
The Lochinvar SSS series water heaters will 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
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
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. |
CAUTION
To reduce the risk of excessive pressures and temperatures in the water heater, install temperature and pressure protective 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.
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. Improper placement and piping of T&P relief valve can cause severe personal injury, death or substantial property damage.
•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:
-SSS031/041 - 3/4" NPT with an AGA Rating of 100,000 Btu/hr.
CAUTION
T&P relief valve is not intended for 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.
-SSS051/081/119 - 3/4" NPT with an AGA Rating of 200,000 Btu/hr.
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