Slant/Fin HWT-120 - Manual (Page 6)

6 INDIRECT FIRED WATER TANK
IV INSTALLATION/PIPING (cont’d)
PIPING
2. Domestic Water
a. Cold Water In. Install brass tee and drain valve (not
provided). Install shutoff valve between water supply
and cold water inlet for ease of service as shown in the
exhibit below.
b. Standard Domestic Hot Water Out. A heat trap will
improve energy efficiency by reducing piping heat loss.
Thermostatic Mixing Valve
At times a thermostatic mixing valve may be recommended
or required. The thermostatic mixing valve
blends domestic cold water with hot water exiting from
the heater, to yield a more constant desired temperature.
Risk of scalding is not eliminated with the use of a
thermostatic mixing valve. Refer to literature provided
by valve manufacturers for recommended installation.
Expansion Tank
When a back flow device or no return valve is installed in
the system a Thermal Expansion Tank designed for use
with potable water will be required. Locate the expansion
tank on the domestic cold water line near the heater
between the back flow device or no return valve and the
heater (see piping diagrams). Refer to the Thermal expansion
Tank manufacturer literature for sizing.
Vacuum Breaker
Slant/Fin recommends that a vacuum breaker be installed on
the domestic piping to the heater. The vacuum breaker
protects the heater in the event that tank pressure falls
below atmospheric pressure.
Temperature & Pressure Relief Valve( T & P)
A T & P is required on all heaters. Install a
T & P valve (long element type) into the separate tapping
designated for the T & P.
Install temperature and pressure protective equipment
required by local codes, but no less than a combination
temperature and pressure relief valve certified as meeting
the requirements for relief Valve and Automatic Shutoff
Devices for Hot Water systems, ANSI Z21.22, by a nationally
recognized testing laboratory that maintains periodic
inspection of listed equipment or materials.
The valve must be oriented, provided with tubing or
otherwise installed so that discharge can exit only within
six (6) inches above, or at any distance below, the structural
floor, and cannot contact any electrical part. The
valve must be piped to an area where discharge will not
cause personal injury or damage the surrounding area.
WARNING!
INSTALL A T & P WITH A RATED CAPACITY THAT IS
EQUAL TO OR GREATER THAN THE OUTPUT OF THE
ENERGY SOURCE.
REMOVAL OF THE T & P, OR FAILURE TO REPLACE
TEMPERATURE- PRESSURE RELIEF VALVE, WILL
RELEASE THE MANUFACTURER FROM ANY CLAIM
WHICH MIGHT RESULT FROM EXCESSIVE
TEMPERATURES AND PRESSURES.