Viessmann VITOCELL 300 EVI Series User manual

Installation Instructions
VITOCELL
r
300
-V
5608 490 v1.2 09/2012
for use by heating contractor
Vitocell 300
EVI Series
Indirect-fired domestic hot water storage tank
53 USG and 120 USG (200 L and 450 L) capacity
Read and save these instructions
for future reference.
IMPORTANT
CAUTION
The heat transfer medium must
be water or other non-toxic fluid
having a toxicity rating or class
of 1, as listed in clinical toxicology
of commercial products, 5th
edition.
This tank version is not suitable
for steam heating applications.
The pressure of the heat transfer
medium must be limited to a
max. of 30 psig by an approved
safety or relief valve.
Please file in Service Binder
Product may not be exactly as shown

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5608 490 v1.2
Vitocell 300-V Installation Instructions
Safety, Installation and Warranty Requirements
Introduction
Please ensure that these instructions are read and understood before commencing installation. Failure to comply with
the instructions listed below and details printed in this manual can cause product/property damage, severe personal
injury, and/or loss of life. Ensure all requirements below are understood and fulfilled (including detailed information
found in manual subsections).
CAUTION
The heat transfer medium must be either potable water
or contain only substances which are recognized as safe
by the U.S. Food and Drug Administration.
The Pressure of the heat transfer medium must be
maintained less than the normal minimum operating
pressure of the potable water system
gLicensed professional heating contractor
The installation, adjustment, service and maintenance
of this equipment must be performed by a licensed
professional heating contractor.
uPlease see section entitled
“Important Regulatory and Installation
Requirements”.
gProduct documentation
Read all applicable documentation before commencing
installation. Store documentation near product in a
readily accessible location for reference in the future
by service personnel.
uFor a listing of applicable literature,
please see section entitled “Important
Regulatory and Installation Requirements”.
gAdvice to owner
Once the installation work is complete, the heating
contractor must familiarize the system operator/
ultimate owner with all equipment, as well as safety
precautions/requirements, shutdown procedure, and
the need for professional service annually before the
heating season begins.
gWarranty
Information contained in this and
related product documentation must
be read and followed. Failure to do
so renders the warranty null and void.
In solar applications

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5608 490 v1.2
Vitocell 300-V Installation Instructions Contents
Safety, Installation and Warranty Requirements..............2
Licensed professional heating contractor.....................2
Product documentation.............................................2
Advice to owner......................................................2
Warranty................................................................2
Important Regulatory and Installation Requirements........4
Codes.....................................................................4
Mechanical room.....................................................4
Working on the equipment........................................4
Technical literature..................................................4
About These Instructions.............................................5
Product Information.....................................................5
53 USG to 120 USG (200 L to 450 L) capacity..........5
Tank Connections.......................................................6
Tank Set-up...............................................................7
53 and 79 USG (200 and 300 Liter) Tank Installation....8
Thermal insulation and thermometer installation..........8
53 to 120 USG (200 to 450 Liter) Tank Installation.......9
Temperature sensor installation (when using
a Vitotronic 200 / 300 or Vitodens 200).....................9
Temperature sensor installation for solar operation...10
120 USG (450 Liter) Installation.................................11
Levelling and bottom thermal insulation....................11
Fitting the thermal insulating jacket..........................12
Fitting the thermometer and thermometer sensor
(if supplied) and covers...........................................13
Aquastat installation (when using a Vitotronic 100)............14
Grounding connection.............................................14
Boiler Water Connections (heat exchanger connection)...15
Recommended piping for solar application
with an additional tank.........................................15
Domestic Water Connections......................................16
Recirculation Connections..........................................18
Saving Energy........................................................18
Multiple Tank Set-up [only for 79 and 120 USG
(300 and 450 L) capacities].......................................19
Pressure Drop Information..........................................21
Installation of Inspection Opening...............................22
Post Installation......................................................22
Service binder........................................................22
Start-up information...............................................22
Introduction
Safety
General Information
Set-up and Connections
Additional Information
Page

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5608 490 v1.2
Vitocell 300-V Installation Instructions
WARNING
If the heating system itself is to be filled with Glycol or
any other antifreeze, the system fill must be of non-toxic
or food grade antifreeze. In any circumstance, a non-toxic
fluid must be used. Ensure a copy of the Material Safety
Data Sheet (MSDS) is supplied to the operator/ultimate
owner of the system. The use of Viessmann supplied
“Tyfocor-HTL” solar fill is recommended for the solar
heating circuit.
Codes
The installation of indirect-fired hot water storage tanks
in boilers and solar system application might be governed
by individual local rules and regulations for this type of
product, which must be observed. Always use latest
editions of codes.
In the Commonwealth of Massachusetts, all plumbing
work must be done by a licensed plumber or gas-fitter
and for gas installations, all gas piping must be done by
a licensed gas-fitter.
Mechanical room
Ensure the mechanical room complies with the
requirements of the system design guideline and/or
Technical Data Manual (available from your Viessmann
sales representative).
The tank must be installed in a mechanical room which is
never subject to freezing temperatures.
Ensure water in tank is drained if not in use and danger of
freezing exists in the mechanical room.
Working on the equipment
The installation, adjustment, service, and maintenance
of this equipment must be done by a licensed professional
heating contractor who is qualified and experienced in
the installation, service, and maintenance of hot water
heating systems. There are no user serviceable parts on
this equipment.
Ensure main power supply to equipment, the heating
system, and all external controls has been deactivated.
Close main oil or gas supply valve. Take precautions to
avoid accidental activation of power during service work.
Safety
Important Regulatory and Installation Requirements
uPlease carefully read this manual prior to attempting
installation. Any warranty is null and void if these
instructions are not followed.
This product must be installed observing not only the
information and instruction provided in the pertinent
product literature (see list on following page), but also
all local, provincial/state plumbing and building codes,
as they apply to this product and all periphery
equipment.
For information regarding other Viessmann System
Technology componentry, please reference
documentation of the respective product (available from
your Viessmann sales representative).
We offer frequent installation and service seminars to
familiarize our partners with out products. Please inquire.
uThe completeness and functionality of field supplied
electrical controls and components must be verified
by the heating contractor. These include low-water
cut-offs, flow switches (if used), staging controls,
pumps, motorized valves, air vents, thermostats,
temperature controls, etc.
Technical literature
Literature applicable to all aspects of the Vitocell:
- Technical Data Manual
- Installation Instructions
- Start-up/Service Instructions
- Operating Instructions and User’s Information Manual
uLeave all literature at the installation site and advise the
system operator/ultimate owner where the literature
can be found. Contact Viessmann for additional copies.

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5608 490 v1.2
Vitocell 300-V Installation Instructions
About These Instructions
Product Information
Take note of all symbols and notations intended to draw attention to potential hazards or important product information.
These include “WARNING”, “CAUTION”, and “IMPORTANT”. See below.
uWarnings draw your attention to the presence of
potential hazards or important product information.
uCautions draw your attention to the presence of
potential hazards or important product information.
uHelpful hints for installation, operation or maintenance
which pertain to the product.
uThis symbol indicates that additional, pertinent
information is to be found.
uThis symbol indicates that other instructions must be
referenced.
WARNING
Indicates an imminently hazardous situation which, if
not avoided, could result in substantial product/property
damage, serious injury or loss of life.
CAUTION
Indicates an imminently hazardous situation which, if not
avoided, may result in minor injury or product/property
damage.
IMPORTANT
u
53 USG to 120 USG (200 L to 450 L) capacity
Indirect-fired domestic hot water storage tank with
one heat exchanger coil for use with hot water heating
boilers, residential/commercial heating plants, and low-
temperature heating systems.
These tank versions are not suitable for steam heating
applications.
General Information

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5608 490 v1.2
Vitocell 300-V Installation Instructions
Tank Connections
Set-up and Connections
Legend
DHW Domestic hot water supply
RT Recirculation tapping
TS/AQ DHW temperature sensor or aquastat of boiler
control (upper indirect coil)
BWS Boiler water supply *1
BWR Boiler water return *1
DCW Domestic cold water supply
*1 The upper indirect coil is provided for connection
to a boiler or a heat pump.
Supplied adaptor sizes Vitocell 300-V
Part Size 53/79 USG
(200/300 L)
120 USG
(450 L)
BBrass cap 1 in. 1 --
ABrass adaptor 1 in. 3 --
CBrass tee 1 in. 1 --
DReducer hex bushing 1 in. x c in. 1 --
FBrass adaptor 1 in. + gasket 2 --
BBrass cap 1a in. -- 1
ABrass adaptor 1a in. -- 5
CBrass tee 1a in. -- 1
DReducer hex bushing 1a in. x c in. -- 1
E Temperature and
pressure relief valve
cin. 1 1

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5608 490 v1.2
Vitocell 300-V Installation Instructions
- For narrow passageways, remove upper and lower
portion of crating and carry DHW tank to its installation
location by means of crating boards mounted on the tank.
- Position tank carefully and remove wood crating.
- Leave adequate clearance to the wall or other objects
enabling easy access to the aquastat (where applicable).
- Install tank(s) on flooring or foundation capable of
supporting the weight of the tank(s) filled with water.
- The tank does not require a special foundation and can
be placed directly on the floor. If, for cleanliness
purposes, the tank is to be kept off the floor, a
foundation can be used for each tank or group of tanks.
Recommended service clearances
Rear in. (mm) 18 (460)
Sides May be reduced if rear pipe connections can
be reached with less clearance
in. (mm) 12 (300)
Top in. (mm) 12 (300)
Front in. (mm) 24 (600)
Minimum clearances to combustibles
All sides in. (mm) 0 (0)
Floor combustible
IMPORTANT
Provide sufficient clearances towards the wall to allow
the aquastat to be operated (if installed).
CAUTION
Install the DHW tank in a frost-protected and draft-free
room. Otherwise it must be drained when not in use, in
order to reduce the risk of damages caused by freezing.
Tank Set-up
Set-up and Connections
1. Apply Loctite 55 as per supplied instructions to each
tank nipple. Use Loctite 55 provided in the installation
fittings package.
2. Connect female ends of brass adaptors to the tank
nipples.

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5608 490 v1.2
Vitocell 300-V Installation Instructions
53 and 79 USG (200 and 300 Liter) Tank Installation
Thermal insulation and thermometer installation
All required components are included in the insulation
jacket carton.
Note: the 53 and 79 USG (200 and 300 L) tank comes
with the insulation jacket installed.
1. Level the DHW tank with its leveling bolts.
2. Remove top cover and the thermal insulation blanket.
3. Insert the thermometer sensor into the tank cap hole
as far as it will go.
4. Secure the sensor with a spring clip. Install the top
cover and the thermal insulation blanket.
IMPORTANT
Do not extend the leveling bolts beyond an overall
length of 1½ in. (35 mm).
IMPORTANT
Never wrap insulating tape around the sensor.
Set-up and Connections

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5608 490 v1.2
Vitocell 300-V Installation Instructions Set-up and Connections
53 to 120 USG (200 to 450 Liter) Tank Installation
1. Carefully pull sensor mounting hardware out from tank
sensor well.
2. Mount sensor on the outside of the sensor spring-clip
(not in the center groove) so that it is flush with the
front of the sensor spring-clip.
3. Push sensor cabling into groove of mounting hardware.
4. Carefully tighten plastic screw to secure sensor cabling
in place.
Temperature sensor installation (when using a Vitotronic
200 / 300 or Vitodens 200)
IMPORTANT
Due to the length of the stainless steel well 15 in. (380 mm),
care must be taken to ensure that the sensing bulb of the
limit is inserted and pushed to the end of the stainless
steel well.
5. Install sensor well and reducing coupling (included in
Connection Fitting Package). Use approved pipe sealant.
6. Mount insulation on sensor well.
7. Insert DHW tank temperature sensor (supplied with
Vitotronic 200 or 300) fully and completely into
sensor well.
8. Carefully tighten screw on sensor well to secure
sensor in place.
IMPORTANT
Never wrap insulating tape around the sensor.
WARNING
To ensure maximum operational reliability, use the sensor
well supplied for the control device sensor or probe.
Use a different stainless steel (1.4571 or 1.4435) sensor
well, if the sensor or probe does not fit into the supplied
sensor well.
Note: When using a Vitotronic 100 boiler control, refer to
page 13 for aquastat installation.

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5608 490 v1.2
Vitocell 300-V Installation Instructions
Temperature sensor installation for solar operation
using 53 and 79 USG (200 and 300 L) tanks
The temperature sensor for solar operation is included in
the solar control unit package.
The brass elbow with sensor well is available as an
option and must be used when solar connection is
required.
1. For solar operation, install the sensor well into the
brass elbow and connect the assembly to the solar
return line.
2. Insert the temperature sensor until it bottoms out
inside the sensor well.
IMPORTANT
Never wrap insulating tape around the sensor. Do not
install solar tank sensor anywhere other than the brass
elbow with sensor well.
1. For solar operation, install the sensor well/brass elbow
and connect the assembly to the solar return line.
2. Insert the temperature sensor until it bottoms out
inside the sensor well.
3. Tighten screws to secure sensor (do not over tighten).
53 to 120 USG (200 to 450 Liter) Tank Installation (continued)
Temperature sensor installation for solar operation
using 120 USG (450 L) tank
The temperature sensor for solar operation is included in
the solar control unit package.
IMPORTANT
Never wrap insulating tape around the sensor. Do not
install solar tank sensor anywhere other than the brass
elbow with sensor well.
The brass elbow with sensor well is available as an option
and must be used when solar connection is required.
Set-up and Connections

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5608 490 v1.2
Vitocell 300-V Installation Instructions Set-up and Connections
120 USG (450 Liter) Tank Installation (continued)
1. Fit the thermal insulation blanket below the tank prior
to the installation of the tank itself.
2. Position and level the DHW tank with its leveling bolts.
Levelling and bottom thermal insulation
All necessary parts for enclosure assembly are packaged
in a separate carton.
CAUTION
The thermal insulation must not come in contact with
open flames. Exercise extreme caution when welding
and soldering.
IMPORTANT
Do not extend the leveling bolts beyond an overall
length of 1½ in. (35 mm).

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5608 490 v1.2
Vitocell 300-V Installation Instructions
120 USG (450 Liter) Tank Installation (continued)
Fitting the thermal insulation jacket
Note: - insulation remnants must not enter the tank
through the tank connections.
- 2 people are recommended to complete this work.
1. Fit both halves of the insulation jacket close to the tank.
Orient the jacket so the profile cutouts match the tank
fittings.
2. At the rear of the tank, install all 6 clip closures evenly
to both halves of the insulation jacket.
3. At the front of the tank, install all 6 clip closures
evenly to both halves of the insulation jacket.
4. At the rear of the tank, tighten all 6 clip closures
until both halves of the insulation jacket meet.
5. At the front of the tank, tighten all 6 clip closures
until both halves of the insulation jacket meet.
Set-up and Connections

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5608 490 v1.2
Vitocell 300-V Installation Instructions Set-up and Connections
120 USG (450 Liter) Tank Installation (continued)
Fitting the thermometer and thermometer sensor
(if supplied) and covers
1. Smooth out the insulation jacket by tapping the jacket
evenly against the tank.
2. Route thermometer capillary tube through the
front cover hole and insulation jacket, then snap the
thermometer in place.
3. Insert the thermometer probe under the clip.
4. Install the front cleanout cover and the front lower
seam cover.
5. Install the upper front seam cover.
6. Install the back seam cover.
7. Insert the thermometer sensor into the tank cap hole
as far as it will go.
8. Secure the sensor with a spring clip.
9. Install the top insulation and press down the edges
as shown.
10.Install the top lid and press the logo Ainto the lid.
Note: Seal the hole in the seam cover below the
thermometer with a cover.

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5608 490 v1.2
Vitocell 300-V Installation Instructions
Aquastat Installation (when using a Vitotronic 100)
Where a Vitotronic 100 and a Viessmann Power/Pump
Control Module (accessory) are utilized to control DHW
production, follow these aquastat mounting instructions:
1. Insert the extended capillary of the aquastat (supplied
with Viessmann Power/Pump Control Module, not
illustrated) fully and completely into sensor well. Mount
aquastat inconspicuously on tank paneling.
Follow instructions below with regard to sensor and
spring clip installation.
... if aquastat is to be mounted remote from the tank well,
2. Align sensor bulb with spring clip.
3. Slide assembly into well.
4. The retention spring clip must press the bulb properly
to ensure surface contact with the well.
... if aquastat is to be mounted directly on the tank well,
5. Mount aquastat with holding clip supplied directly onto
well. Bend capillary tube into groove opening to allow
for mounting of aquastat.
Grounding connection
Connect the grounding in accordance with the requirements
stipulated by your local electricity supply company and
current local regulations.
WARNING
To ensure optimum, safe operation, the supplied
stainless steel well must be installed. The well diameter
is large enough to accommodate a wide variety of
sensing bulbs.
Always use spring clip to ensure proper contact of
capillary bulb against the stainless steel well for proper
sensing/heat transfer!
Probe style aquastat
WARNING
Domestic hot water temperatures over 125° F (52° C)
can cause severe burns instantly or death from scalds.
Children, disabled and elderly are at highest risk of
being scalded.
Feel water before bathing or showering.
Temperature limiting valves are available and must
be used where domestic hot water storage tank
temperatures exceed 140° F (60° C).
WARNING
The operating aquastat and any secondary high limit
aquastat of the tank must be set such that the DHW
temperature inside the tank never exceeds 203° F (95° C).
IMPORTANT
Use a Loctite 55 string and pipe dope on all threaded
nipples on tank.
Set-up and Connections

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5608 490 v1.2
Vitocell 300-V Installation Instructions Set-up and Connections
Boiler Water Connections (heat exchanger connection)
Legend
A Solar collector
B High limit safety cut-out
C Filling valve
D Solar-Divicon
E Vitocell-V 300
F Individual DHW tank heating system
GAnti-scald temp[ering valve
1. For boiler water supply temperatures over 203° F (95° C):
Remove plastic supply and return grommets
(grommets are left-threaded).
2. Pipe supply line with an incline and install an air vent
valve at the highest point.
3. For boiler water supply temperatures over 230° F
(110° C):
Install a type-tested high limit safety cut-out, if no other
has previously been installed in this system. For this
purpose, install a dual thermostat (high limit thermostat
and high limit safety cut-out).
4. Close off test nipples which are not used for the
installation of a probe or sensor.
IMPORTANT
Recommended piping for solar application with an additional tank
Use a Loctite 55 string and pipe dope on all threaded
nipples on tank.
WARNING
Due to the potentially high DHW temperatures generated
by the solar heating system, the domestic hot water
temperature must be limited to a maximum of 140º F (60º C)
by installing a anti-scald tempering valve. The tempering
valve does not completely eliminate the risk of scalding at
the tap. The installation of a mixing tap is recommended.

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5608 490 v1.2
Vitocell 300-V Installation Instructions
Domestic Water Connections
Use a Loctite 55 string and pipe dope on all threaded
nipples on tank.
IMPORTANT
Note: - Connect all pipe work with detachable fittings.
- Seal connections that are not required with red brass
caps.
- Equip the DHW circulation pipe with circulation
pump, check valve and time switch. Gravity
operation is only feasible to a limited degree.
- Always install DHW group of tanks with
connected DHW circulation.
1. Pipe together boiler and tank as illustrated. Connections
must be accessible for service (use factory supplied
adaptors).
2. Insulate domestic hot water supply piping.
Legend
A Spring-loaded flow check valve
B Discharge pipe
C Anti-scald tempering valve (field supplied)
SV Shut-off valve
FV Flow check valve
PR Pressure reducing valve
D Drain
DCW Cold water supply lines
PGC Pressure gage connection
E Precharged expansion tank (required where backflow
preventer is installed; check local plumbing codes
and requirements)
BP1 Backflow preventer
BP2 Backflow preventer
T&P Temperature and pressure relief valve
DW Water filter
DHW Domestic hot water supply
RP Recirculation pipe
RPU Recirculation pump
IMPORTANT
This is a simplified conceptual drawing only! Piping and
necessary componentry must be field verified. Proper
installation and functionality in the field are the responsibility
of the heating contractor.
Set-up and Connections

17
5608 490 v1.2
Vitocell 300-V Installation Instructions Set-up and Connections
Domestic Water Connections (continued)
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.
The valve supplied with the tank is manufactured by Watts
Industries (Model 40XL-8) set to 100 psig for Canadian
installations and set to 150 psig for US installations
(where applicable). 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 in. 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 in.
(1.9 cm) 7and 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.
Always ensure the use of type 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 discharge line for the T&P valve must be oriented to
prevent scalding of attendants.
- 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.
Watts Model
40XL-8
100 psig
(Canada) where
CRN is required
150 psig
ASME pressure
steam rating
998 MBH 1438 MBH
CSA
temperature
steam rating
205 MBH 205 MBH
Relief
temperature
210° F (99° C) 210° F (99° C)
Inlet thread c” male c” male
Outlet thread c” female c” female
- 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 tested under
ANSI Z21.22 Code for Relief Valves and Automatic
Gas Shut-off Devices for Hot Water Supply Systems.

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5608 490 v1.2
Vitocell 300-V Installation Instructions
Recirculation Connections
Pipe domestic hot water supply piping with tank as
illustrated. Connections must be accessible for
service (use factory supplied adaptors).
Install recirculation pump, flow check valve and
recirculation timer (for shut-down during off-hours
where feasible) on the recirculation piping side.
Gravity circulation of the recirculation system is
restricted due to the upward-curved domestic hot
water discharge piping inside the tank.
Connect tanks to existing recirculation piping. Cap off
unused recirculation connections of individual tanks.
Saving Energy
A timer on the recirculation pump reduces the heat
loss significantly in commercial applications during
times when no or reduced demand for domestic hot
water occurs.
Connection of a recirculation system in a multiple tank installation for systems utilizing boilers or remote heating
plants without low temperature boiler return water
Connection of a recirculation system in a multiple tank installation for remote heating plants with low temperature
boiler return water limit and/or for multiple recirculation lines
Legend
A Drawpoints
B Recirculation piping
C Circulation pump
D Spring-loaded flow check valve
Legend
A Drawpoints
B Recirculation piping
C Circulation pump
D Spring-loaded flow check valve
E Domestic cold water supply
F Domestic hot water supply
G Secondary high limit aquastat location
HAir vent
E Domestic cold water supply
F Domestic hot water supply
G Secondary high limit aquastat location
HAir vent
H
H
Set-up and Connections

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5608 490 v1.2
Vitocell 300-V Installation Instructions Set-up and Connections
Multiple Tank Set-up [only for 79 and 120 USG (300 and 450 L) capacities]
IMPORTANT
Two tanks, each with 79 USG (300 L) content, or up to
four tanks, each with 120 USG (450 L) content, may be
installed side-by-side.
The tanks are controlled via one DHW tank aquastat.
Individual control of tanks within the group of tanks is
therefore not possible.
If control of individual tanks within a group of tanks is
necessary, two alternatives exist. Either a 4-tank group
can be separated into smaller groups, i.e. two batteries
each consisting of two tanks (one DHW tank aquastat
controls each group), or all tanks should be installed
individually, i.e. individual tank set-up (one DHW tank
aquastat controls each tank).
1. Install aquastat in the boiler water supply of the last
tank receiving the boiler water in a group of tanks (see
illustration).
2. Install domestic cold and hot water header lines (see
illustration).
3. Install boiler water supply and return header lines (see
illustration).
4. Make final cold and hot water connections.
Both the boiler supply/return header and the domestic
hot/cold water header must be installed in a reverse
return method. This ensures uniform heating of all tanks
in the group. Header sizes for batteries up to four 79 to
120 USG (300 to 450 L) tanks are listed below.
5. Insulate header piping lines.
CAUTION
In commercial installations, we recommend the installation
of an additional high limit aquastat in the main discharge
pipe of domestic hot water from a group of tanks into
the system, and to wire this additional high limit aquastat
in series with the operating aquastat.
Storage capacity / Tank USG (L) 79 (300) 120 (450)
Number of tanks 2 2 3 4
Layout 33 33 333 3333
Connections (individual tank)
Heating water supply/return (common header size) 72 2 2 2b
Domestic cold/hot water (common header size) 71a1a1b2
Recirculation tapping 711a1a1a
Legend
ADomestic hot water supply and T&P valve connection
BBoiler water supply
C Operating aquastat
D Boiler water return
EDomestic cold water
FDrain
GAir vent

20
5608 490 v1.2
Vitocell 300-V Installation Instructions
Set-up and Connections
All piping reverse return or use balancing valves.
1. Pipe together boiler and tanks as illustrated.
Connections must be accessible for service (use factory
supplied adaptors).
2. For boiler water supply temperatures over 203° F (95° C):
Remove plastic supply and return grommets (grommets
are left-threaded).
3. Pipe supply line with an incline and install an automatic
air vent at the highest point.
4. Install boiler sensor in sensor well (see page 9).
5. Insulate piping.
Legend
A Group of DHW tanks
B Sensor/Operating aquastat well
D Boiler water return
E Boiler water supply
F Domestic cold water supply
G Domestic hot water
H Drain
K Air vent
L Secondary high limit aquastat location
IMPORTANT
IMPORTANT
The circulation pump is activated by the operating aquastat
or by the control system installed. The operating aquastat
should be mounted on the tank which receives the boiler
water supply last.
Viessmann recommends the installation of an additional
high limit aquastat in the main discharge pipe of the DHW
system. This aquastat should be wired in series with the
operating aquastat and should be set approximately 9° F
(5° C) higher than the operating aquastat.
Use Loctite 55 pipe sealing cord and pipe dope on all
threaded stainless steel nipples on tank.
Multiple Tank Set-up [only for 79 and 120 USG (300 and 450 L) capacities] (continued)
Recommended piping of multiple tanks