11
4
Domestic side piping
Basic domestic piping
Figure 4-4 on page 17 shows typical domestic water and space
heating piping for a Strato-Therm+ tank. The stainless steel coil
requires properly sized piping and a properly sized pump to
maintain adequate domestic hot water delivery. Refer to Tables
4D and 4E on page 14 and 15 for domestic coil pressure drop.
The functions of the components shown are as follows:
a. Shut-off valves (recommended) - Used to isolate the
appliance for servicing.
b. Backflow Preventer (required by some codes) - Used to
prevent water from backing out of the indirect coil and
into the main potable water supply in the event that inlet
water pressure drops.
c. Expansion Tank (required for thermal expansion) - Tank
absorbs the increased volume caused by heating water.
Use an expansion tank designed for use on domestic water
systems. Refer to the expansion tank manufacturer’s
instructions for proper sizing and use.
NOTICE
If an expansion tank is used, do not put any
valves between the expansion tank and tank
inlet.
d. Shock Arrestor (required by some codes) - Used to allow
water to accelerate or decelerate without a sudden change in
pressure.
NOTICE
Be sure to field-install plugs or caps on any
tank tappings that are not in use.
e. Circulation Pump (recommended) - Used to circulate
and maintain hot water within the piping system.
f. Check Valve (required by some codes) - Used to allow
water to flow in only one direction, preventing back-flow.
g. Drain (required) - Used to drain the tank for inspection or
servicing.
h. Mixing valve (required) - Used to mix hot water with cold
water to ensure constant, safe outlet temperatures.
i. Unions (optional) - Used to disconnect the tank in the
unlikely event that this is necessary for service.
Because hot water is always circulating in the hot water branch,
the entire branch should be insulated to prevent excessive heat
loss.
When a hot water recirculation system is used there are two
piping arrangements that can be applied to the Strato-Therm+.
The first arrangement is for use in systems with up to 2 gal/
min circulation and requires the purchase of a recirculation
lance assembly (FIG. 4-5, page 18). The second arrangement
is for use in systems with greater than 2 gal/min circulation
that require higher performance and temperature (FIG. 4-6,
page 18).
Domestic water piping for distant fixtures
In some cases the furthest fixture may be located far from the
tank. This may result in an unacceptable delay before hot water
reaches these distant fixtures. Even if all the fixtures are located
relatively close to the tank, it may be desired that hot water be
instantly available to all fixtures.
To prevent delays, return circulation piping with a check valve
that allows flow to the domestic hot water outlet. This should
be installed on each branch circuit at the farthest fixture or
device, so that hot water is supplied upon demand. Traditional
recirculation piping is illustrated in FIG. 4-1, page 12.
Installation & Operation Manual
