17
5696 675 - 04
Vitocell 300-H, EHA Series Installation
Connections
Domestic Water Connections
(continued)
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 in.
(1.9
cm)
7
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
not
threaded.
Always ensure the use of approved devices.
Safety devices include the following components:
- Isolation valves
- Drain valve
- Pressure reducing valve
where required by local jurisdiction
- Drinking water filter
where required by local jurisdiction
- 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.
- 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.
IMPORTANT
In situations where a booster pump is used to maintain
DHW pressure, Viessmann strongly recommends the
installation of an oversized large 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.
WARNING
The valve test lever must be operated at least once per
year by the owner 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
The discharge line for the T&P valve must be oriented to
prevent scalding of attendants.
- Do
not
route discharge line directly to the outdoors.
- Do
not
install any type of valve or restriction of any
kind between the tank and the T&P valve, or
between the T&P valve and the discharge line outlet.
- 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 a maximum operating
pressure of 150 psig.
The T&P valve supplied with the tank is tested under
ANSI Z21.22 Code for Relief Valves and Automatic
Gas Shut-off Devices for Hot Water Supply Systems.
T&P Valve set pressure
150 psig
ASME pressure steam rating
see ratings marked on
the T&P valve
CSA discharge capacity
205 MBH
Relief temperature
210°F (99°C)
Inlet thread
c
” male
Outlet thread
c
” female
