Set-up and Connections
17
Domestic Water Connections
(continued)
Always ensure the use of type approved devices. Safety devices include the following components:
H
Isolation valves
H
Drain valve
H
Pressure reducing valve
where required by local jurisdiction
H
Drinking water filter
where required by local jurisdiction
H
Backflow preventer
Where backflow preventers are
required, a domestic water expansion
tank installation is required in the cold
water inlet piping before the cold
water enters the tank. The backflow
device must be installed according to
the manufacturer’s installation
instructions. Observe local codes and
regulations.
H
Tempering valve
A tempering valve must be field
installed where storage tank
(domestic hot water temperature)
exceeds local restricted temperatures
or 140°F / 60°C. Check code
requirements.
In situations where a booster pump is
used to maintain DHW pressure,
Viessmann strongly recommends the
installation of an oversized expansion tank
to ensure longer, less frequent pump
cycles with less severe pressure
gradients. If possible, use flexible piping
before and after booster pump to isolate
system piping from vibration and shocks.
H
Temperature and pressure
relief valve
A temperature and pressure relief
valve (T&P valve) is supplied with the
tank. The heating contractor must
install the valve on each tank in a
method meeting code requirements.
If local codes require a different relief
valve, consult Viessmann
Manufacturing for a substitute valve.
The tank is approved for 150 psig.
Maximum operating pressure is 150
psig.
The T&P valve supplied with the tank
is manufactured by Watts Industries
(Model 40XL-8), set to 150 psig for
US and Canadian installations (100
psig for Canadian installations for
120 USG / 450 ltr tank size only). The
valve is ASME pressure steam rated
for 998 MBH and CSA temperature
steam rated for 200 MBH.
It is tested under ANSI Z21.22 Code
for Relief Valves and Automatic Gas
Shut-off Devices for Hot Water
Supply Systems. The relief
temperature is set at 210°F / 99°C.
The valve has a male threaded inlet
and female threaded outlet, both ¾”
sizes.
Proper installation of the T&P valve
shall include all of the following:
- The T&P valve shall be installed in the
pipe connection point marked TPV in
the tank instruction manual.
- The discharge line from the T&P valve
shall be ¾” / 1.9 cm
∅
and run to a
safe place of discharge approximately
1 ft / 30 cm above the floor, close to
a floor drain.
- The discharge line must be as short
as possible and pitch downward from
the T&P valve and terminate plain.
- Do
not
route discharge line to the
outdoors.
- Do
not
install any type of valve or an
obstruction of any kind between the
tank and the T&P valve, or between
the T&P valve and the discharge line
outlet.
5285
658
v2
.1
IMPORTANT
The discharge line for the T&P valve
must be oriented to prevent scalding
of attendants.
WARNING
The valve test lever must be operated
at least once per year by a licensed
professional heating contractor to
ensure that waterways are clear. A
licensed professional heating
contractor shall reinspect the T&P
valve at least once every three years.
Failure to inspect can result in unsafe
temperature or pressure build-up,
which can result in death, serious
injury or substantial product/property
damage.
WARNING
Summary of Contents for Vitocell-B 100 CVB Series
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