Viessmann DN25B Dimensions and installation guide

997692210VIEUS0x-mub-en – V01 05/2014 1
Solar-Divicon, DN25B
Installation, Start-up and
Service Instructions
For use by the heating contractor
Please file in Service Binder

Solar-Divicon DN25B Installation, Start-up, Service
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Table of Contents
1For your safety .................................................................................................................................................. 3
1.1About this manual ............................................................................................................................................... 3
1.2Designated use ................................................................................................................................................... 3
1.3Qualification of the installer ................................................................................................................................. 3
1.4Hand-over of the system [specialist] ................................................................................................................... 4
1.5General safety instructions .................................................................................................................................. 4
1.6General instructions regarding solar fluid ............................................................................................................ 5
2Description of the product .................................................................................................................................. 6
3Assembly and installation [specialist] ................................................................................................................. 7
4Commissioning [specialist] .............................................................................................................................. 10
4.1Flushing and filling the solar circuit [specialist] .................................................................................................. 11
4.2Preparation for flushing [specialist] ................................................................................................................... 13
4.3Flushing and filling [specialist] ........................................................................................................................... 13
4.4Setting the solar loop flowrate [specialist] ......................................................................................................... 15
5Cleaning .......................................................................................................................................................... 16
6Maintenance and decommissioning [specialist] ............................................................................................... 16
6.1Partial draining of the solar installation [specialist] ............................................................................................ 17
6.2Complete draining of the solar installation [specialist] ....................................................................................... 17
6.3Replacing the pump [specialist] ........................................................................................................................ 18
6.4Replacing the gaskets in the solar station [specialist] ....................................................................................... 18
6.5Dismounting [specialist] .................................................................................................................................... 19
7Application range of the check valves [specialist] ............................................................................................. 20
8Spare parts [specialist] .................................................................................................................................... 21
9Technical data and pressure drop characteristic .............................................................................................. 22
9.1Pressure drop characteristic ............................................................................................................................. 2 3 
10Commissioning log .......................................................................................................................................... 24

Solar-Divicon DN25B Installation, Start-up, Service
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
1 For your safety
Carefully read this manual before installation and
commissioning. Non-observance of the instructions
in this manual may lead to serious material damage
and serious injuries that may result in death.
Keep this manual in close proximity of the system for
later use.
Indicates that there is risk of
death, serious injuries or
considerable material
damage if suitable safety
precautions are not taken.
Indicates that there is a risk
of light injuries if suitable
safety precautions are not
taken.
Indicates that there is a risk
of material damage if suitable
safety precautions are not
taken.
1.1 About this manual
This manual describes the function, installation,
commissioning and operation of the solar stations
Solar-Divicon DN25B.
The chapters called [specialist] are only addressed
to installation contractors.
For other components of the solar installation, such
as collectors, storage tanks, expansion tanks, and
controllers, please refer to the instructions of the
corresponding product.
1.2 Designated use
The solar station is a pre-assembled fitting assembly
checked for tightness and used for recirculating the solar
fluid in a closed loop solar circuit. The solar station must
only be used in solar thermal systems as pumping station
in the solar circuit, taking into consideration the technical
limit values indicated in this manual. The station may only
be assembled indoors. The station must be assembled
and operated as described in this manual!
Unintended use of the solar station will invalidate any
liability claims.
Only use accessories from Viessmann.
The wrapping materials are made of recyclable materials
that can be recycled by standard recycling operations.
1.3 Qualification of the installer
Installation and commissioning of this equipment
should be done by qualified installers [specialist] in
accordance with local, state, provincial, and federal
codes which may be applicable.
The following must also be observed during
installation and commissioning:
Relevant regional and national regulations (for
example Occupational Safety and Health Act)
Relevant accident prevention regulations (for
example of the Employer's Liability Insurance
Association)
Instructions and safety instructions mentioned in
this manual

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1.4 Hand-over of the system [specialist]
After installation and commissioning, the installer is
responsible for familiarizing the end user with the functions
of the system and the basic safety measures.
After commissioning, fill in the log on the last page of
this manual.
Hand the manual over to the end user and instruct
them to to keep the manual in close proximity to the
system.
Instruct the end user to have the solar station
serviced and repaired by a specialist only.
The controller settings must not be changed by the
customer.
Explain to the end user the function of the system and
of the safety devices. Point out to the end user that
the shell must remain mounted during operation and
that the ball valves in the temperature gauges and
flowmeter must always be open.
1.5 General safety instructions
Before installing and commissioning the product, you must read and observe the following safety instructions:
Danger of scalding due to escaping
vapor!
Flush and fill the system only if the
collector temperatures are below
150 °F (70 °C).
Connect a discharge line to the
safety assembly. Observe the
instructions regarding the pressure
relief valve.
The pressures calculated by the
installation planner for the
expansion tank and the operating
pressure of the installation must be
set prior to filling system
.
Material damage due to mineral oils!
Mineral oil products permanently damage the EDPM
sealing elements, resulting in a loss of their sealing
characteristics. We cannot be held liable for damage
caused by seals thus damaged, nor will we offer a
replacement under warranty.
It is imperative to prevent the EPDM sealing
elements from making contact with substances
containing mineral oils.
Use silicone- or polyalkylene-based lubricants free of
mineral oil, such as Unisilikon L250L and Syntheso
Glep 1 from the company Klüber or a silicone spray
Personal injury and material
damage caused by excess
pressure!
Closing both ball valves will disconnect
the safety assembly from the heat
exchanger. Heating the storage tank
can result in the formation of high
pressures, which may lead to material
damage and personal injury!
In operation, the ball valves with
temperature gauges and the ball
valve at the flowmeter must always
be open.
Close the ball valves only when
service is required.
Risk of burns!
The valves, fittings and the pump may
heat up to more than 212 °F (100 °C)
during operation.
The shell must remain closed during
operation.

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1.6 General instructions regarding solar fluid
Only use solar fluid specified in the Vitosol Collector Installation Manuals and the Vitosol Operating and Service
Instructions.
Also refer to these manuals to determine the following:
Solar fluid fill pressure
Fluid volume required to fill system
pH testing
Maintenance requirements.
Propylene glycol: Hazardous in case of ingestion!
Propylene glycol is hazardous in case of ingestion.
It is irritant in case of eye or skin contact.
Wear chemical resistant protective gloves and safety
glasses with side-shields when handling propylene
glycol mixtures.
Observe the instructions of the antifreeze
manufacturer.
It often happens that solar thermal systems cannot be completely drained after flushing. Thus, there is a risk of frost
damage when flushing with water. Therefore, the solar thermal system should only be flushed and filled with the solar
fluid used later on.
All components in the solar station are resistant to a percentage of propylene glycol of up to 50%.

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2 Description of the product
Assembly example
The solar station is mounted on a wall support and held
by clip springs. The station contains important valves,
fittings and safety equipment for operating a solar thermal
system:
1.1 Return to the collector field
1.2 Ball valve with temperature gauge in the return
equipped with replaceable spindle (blue)
1.3 Pressure relief valve, 87 psi (6 bar)
1.4 Fill valve
1.5 Connection for the expansion tank
1.6 Pressure gauge 87 psi (6 bar)
2 Solar pump
3.1 Ball valve in flowmeter
3.2 Drain valve
3.3 Flowmeter
3.4 Return from the storage tank
4.1 Supply to the storage tank
4.2 Airstop equipped with manual bleeder
5.2 Ball valve with temperature gauge in the supply
equipped with replaceable spindle (red)
5.1 Supply from the collector field

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3 Assembly and installation [specialist]
The solar station may only be installed indoors with a power supply of 120 V / 60 Hz. The installation site must be dry,
stable and frost-free.
Solar-Divicon DN25B Installation Steps:
1. Remove the station from the packaging.
2. Pull off the front shell.
3. Hold the solar station to the mounting location and
level the unit. Mark the mounting hole locations
(next to the temperature gauges) onto the mounting
surface.
4. Drill the holes into the mounting surface, and fasten
the solar station to the wall by means of the
enclosed screws and, if required, the enclosed wall
anchors.
Material damage due to high temperatures!
Since the solar fluid may be very hot near the
collector, the fitting assembly must be installed at a
sufficient distance from the collector field.
It may be necessary to install an upstream tank, in
order to protect the expansion tank

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5. Connect the solar station to the system by means
of copper or stainless steel pipes
⑤ Supply from collector field
① Return to the collector field
④ Supply to the storage tank
③ Return from the storage tank
All pipe connections are designed as cutting-ring
compression fitting 1" copper pipe. Pipe size can be
reduced to ¾” copper if required.
Assembly of the cutting-ring compression fitting:
Push the union nut ②and the cutting ring ③onto the 1” copper
pipe ①. The pipe must protrude at least ⅛" (3 mm) from the cutting
ring in order to ensure the force transmission and the sealing.
Insert the support sleeve ④into the copper pipe.
Insert the copper pipe with the plugged-on individual parts (②, ③
and ④) all the way into the housing of the cutting-ring fitting ⑤.
First tighten the union nut ②manually.
Tighten the union nut ②by rotating it by one full turn.
Secure the housing of the cutting-ring fitting ⑤ against distortion in
order to avoid damaging the sealing ring.
6. Connect a discharge line to the connection (1.3) at
the pressure relief valve. Conduct the discharge
line into a heat-resistant container. Secure the
discharge line such that in the event of escaping
vapor people in the vicinity are not put at risk.
7. Connect the connecting line for the expansion
tank below the pressure gauge (1.5).
8. Adapt the initial pressure of the expansion tank to
the system and connect the expansion tank.
Observe the manufacturer's separate instructions
of the expansion tank! Also observe the layout of
the installation planner.
9. Check all pipe connections and retighten if
necessary.

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Risk of electric shock!
Prior to commencing electrical work, disconnect the main power supply!
Only after completing all installation work, flushing and filling should the mains plug be plugged
into an outlet! This avoids an unintentional start of the pump motor.
10.Connect the 120V power supply from the solar
controller to the solar station pump. The controller
must be provided on site. Observe the separate
instructions of the controller!
Wiring can run in the slots in the back foam
insulation panel of the solar station.
Observe all local electrical code requirements.
The assembly of the solar station is now complete,
and you can commission the station.
120V power
supply
connection
Electric
cable slots

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4 Commissioning [specialist]
Before commissioning the solar station, you must read and observe the following safety instructions:
Risk of burns and scalding!
The valves and fittings may heat up to
more than 212 °F (100 °C). During
flushing, filling and venting, the solar
fluid can escape as vapor and result in
scalding.
Flush and fill the system only if the
collector temperatures are below
150 °F (70 °C).
Propylene glycol: hazardous in case of ingestion!
Propylene glycol is hazardous in case of ingestion.
It is irritant in case of eye or skin contact.
Wear chemical resistant protective gloves and safety
glasses with side-shields when handling propylene
glycol mixtures.
Observe the instructions of the antifreeze
manufacturer.
Risk of frost!
It often happens that solar thermal systems cannot be
completely drained after flushing. Thus, there is a risk of
frost damage when flushing with water.
Therefore, the solar thermal system should only be
flushed and filled with the solar fluid used later on.
Use a water and propylene glycol mixture with max.
50% of propylene glycol as solar fluid, in order to
avoid damaging the seals.
Note regarding the commissioning sequence
When commissioning the system, first fill the storage
circuit and then the solar circuit. This guarantees
that any absorbed heat can also be dissipated.

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4.1 Flushing and filling the solar circuit [specialist]
The fill and drain connections required for flushing and filling have been integrated into the solar station.
In order to flush any dirt particles that may still be present out of the system, use only flush and fill stations equipped with
suitable micro filters.
Ball valve with integrated check valve
(Normal direction of flow in the picture: downstream)
0° 45° 90°
Check valve in operation,
through-flow in flow direction
only (normal operating position).
Check valve not in operation,
through-flow in both directions
(use this positioning to help purge air
during intial commissioning).
Ball valve closed,
no through-flow (service postion).
14 mm

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Airstop
The airstop with manual bleeder is used to bleed the solar thermal
system. To ensure a perfect ventilation of the solar circuit, the flow
velocity must be at least 0.3 m/s in the supply.
Pipe
diameter Flow rate
at 0.3 m/s
[USgpm]
Flow rate
at 0.3 m/s
[l/min]
¾" 1.49 5.6
1" 2.3 8.8
The air liberated from the solar fluid is collected in the upper area
of the airstop and can be discharged via the vent plug [4.2].
Danger of scalding due to escaping vapor!
The escaping solar fluid can have a temperature of more than 212 °F (100 °C) and cause scaldings.
Carefully open the vent plug and close it again, as soon as medium escapes.
Venting the solar thermal system after commissioning
Immediately after installation, vent the solar thermal system daily
and then weekly or monthly, depending on the vented air quantity.
This ensures optimum operation of the solar thermal system.
Check the system pressure after venting and increase it to the
prescribed operating pressure, if necessary.
4.2

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4.2 Preparation for flushing [specialist]
The solar circuit is flushed in the direction of flow.
1. Disconnect the expansion tank from the solar
thermal system! Please observe the manufacturer's
instructions.
2. Open the check valves in the supply and return by
turning the ball valves (1.2 and 5.2) to position 45°
(see page 11).
3. Close the ball valve (3.1) in the flowmeter.
4. Connect the flush and fill station to the solar station:
- Pressure hose to the fill connection (1.4)
- Flushing hose to the drain connection (3.2).
4.3 Flushing and filling [specialist]
1. Open the fill and drain valves (1.4 and 3.2).
2. Put the flush and fill station into operation and keep
flushing until clear medium escapes.
3. Vent the solar thermal system several times at the
vent plug of the airstop (4.2) during flushing until the
solar fluid escapes without forming bubbles
(see page 12).
4.2
Compact mobile charging cart for flushing,
filling and purging the solar circuit

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4. Close the drain valve (3.2) with the filling pump
running and increase the system pressure,
depending on the design of the system, to max.
5 bar. Refer to “Vitosol Operating and Service
Instructions” for instructions on calculating the
correct fill pressure. The pressure can be read on the
pressure gauge. Close the fill valve (1.4) and switch
off the pump of the flush and fill station.
Check the pressure on the pressure relief valve
(87 psi/6 bar)!
5. Check at the pressure gauge if the system pressure
is dropping and eliminate any leaks, if present.
6. Reduce the pressure on the drain valve (3.2) to the
system-specific pressure.
7. Connect the expansion tank to the solar circuit and
set the operating pressure of the solar thermal
system by means of the flush and fill station (for the
required expansion tank pressure settings, refer to
“Vitosol Operating and Service Instructions”).
8. Close the fill and drain valves (1.4 and 3.2).
9. Open the ball valve (3.1) in the flowmeter.
10. Set the check valves in the ball valves (1.2 and 5.2)
to operating position (see page 11).

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Risk of electric shock!
Check if the sensors and the pump are properly connected to the controller and if the controller
housing is closed. Only then should the mains plug of the controller be plugged into an outlet.
11. Connect the controller (to be provided on site) to the
power supply and set the solar circuit pump in the
manual mode to ON as described in the controller
manual. Run the solar circuit pump at maximum
rotation speed for at least 15 minutes.
In the meantime, vent the solar thermal system
several times at the vent plug of the airstop until the
solar fluid escapes without forming bubbles
(see page 12).
If necessary, increase the system pressure to the
operating pressure again.
12. Remove the hoses of the flush and fill station and
screw the the closure caps on the fill and drain
valves.
Note: The closure caps are only for protection
against soiling. They have not been constructed for
high system pressures, their tightness being
guaranteed by the closed ball valves.
Correct
Incorrect
4.4 Setting the solar loop flowrate [specialist]
Scale: 1-10 USgpm
(The unit is specified on the scale)
Reading edge = Upper edge of the floating body
Example: approx. 2 USgpm
Refer to “Vitosol Operating and Service Instructions”)
for the correct adjustment of the flow rate.
1. Set the desired max. flow rate via the rotation
speed of the solar pump. The controller will set the
speed accordingly.
In exceptional cases, the flow rate can also be
reduced via the ball valve (3.1).
2. Mount the front shell on the solar station.
3. Set the controller to automatic mode (see
controller manual).

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5 Cleaning
Risk of burns!
The valves, fittings and the pump
may heat up to more than 212 °F
(100 °C) during operation.
The shell must remain closed
when cleaning.
Clean the solar station only from the outside with a damp cloth. Never use scouring or sand-containing cleaning agents.
6 Maintenance and decommissioning [specialist]
Before maintaining and decommissioning the product, you must read and observe the following safety instructions:
Risk of electric shock!
Disconnect all electrical devices in
the heating circuit from the power
supply before carrying out
maintenance work or
decommissioning!
Secure the electrical devices
against being switched on again.
Risk of burns and scalding!
The valves and fittings may heat up
to more than 212 °F (100 °C).
During maintenance or
decommissioning, the solar fluid
may escape as vapor and result in
scalding!
Flush and fill the system only if the
collector temperatures are below
122 °F (50 °C).
Wait until the solar fluid has cooled
down to 122 °F (50 °C).

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6.1 Partial draining of the solar installation [specialist]
Partial draining allows components in the station below the ball valves (5.2 and 1.2), for example the pump, to be
replaced, without having to drain the collector array and piping.
Danger of scalding due to hot solar fluid!
The escaping solar fluid can be very hot.
Position and secure the heat-resistant collecting container such that persons nearby and the
environment are not put at risk when the solar thermal system is drained.
6.2 Complete draining of the solar installation [specialist]
Complete draining enables replacement of the solar fluid, dismounting of the solar station and replacement of seals
above the ball valves (5.2 and 1.2).
1. Perform partial draining as described above.
2. Open the check valves in the supply and return ball
valves (5.2 and 1.2) by rotating them to the 45°
position (see page 11).
3. To accelerate draining of the solar circuit, you can
open the bleeding device, if present, at the highest
point of the solar thermal system.
4. Dispose of the solar fluid observing the local
regulations.
1. Disconnect the controller from the power supply and
secure it against being switched on again.
2. Close the ball valves in the supply and return ball
valve [5.2|1.2] by rotating them to the 90° position
(90°, see page 11).
3. Connect a heat-resistant hose to the drain valve [3.2].
Make sure that the solar fluid is collected in a heat-
resistant container.
4. Open the drain valve [3.2].
5. Carefully open the vent plug at the airstop [4.2] and
close it again (see 12).

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6.3 Replacing the pump [specialist]
1. Perform partial draining as described in section
6.1 Partial draining of the solar installation [specialist].
2. Disconnect the pipe joint between the solar station and
the storage supply.
3. Dismount the flowmeter (3.3).
4. Dismount the pump.
5. Install the new pump. Do not forget to insert new
gaskets.
6. Mount the flowmeter (3.3).
7. Connect the solar station and the system again by
means of pipes.
8. Check all screw connections and retighten them,
if necessary.
9. Open the ball valves (5.2 and 1.2).
10. If the system pressure no longer corresponds to the
operating pressure, repeat commissioning as
described from page 10 onward.
6.4 Replacing the gaskets in the solar station [specialist]
1. Gaskets below the ball valves: Perform partial draining
as described in section 6.1 Partial draining of the solar
installation [specialist].
Gaskets above the ball valves: Drain the solar thermal
system completely as described in section 6.2
Complete draining of the solar installation [specialist].
2. Dismount individual components of the station and
insert new gaskets.
3. Re-assemble the station.
4. Connect the station and the system by means of pipes.
5. Check all screw connections and retighten them,
if necessary.
6. Open the ball valves (5.2 and 1.2).
7. If the system pressure no longer corresponds to the
operating pressure, repeat commissioning as
described from page 10 onward.

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6.5 Dismounting [specialist]
1. Drain the solar thermal system completely as
described in section 6.2 Complete draining of the
solar installation [specialist].
2. Disconnect the pipe joints with the solar thermal
system.
3. To remove the solar station from the support, pull
out the clip springs sideways using a screwdriver.
4. Pull out the station towards the front.

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7 Application range of the check valves [specialist]
Within their application range, the two check valves in the solar station prevent unwanted gravity circulation.
The efficiency of the check valves depends on:
the installation height
the temperature difference between the storage tank and the collector
the type of heat transfer medium
In the diagram below you can see whether the check valves integrated in the stations are sufficient . If the
check valves are not sufficient, you need to install additional components to prevent gravity circulation. You can
mount components such as syphons ("heat traps"), 2-way valves (zone valves) or additional check valves.
Example:
You would like to install a Solar-Divicon solar station. The station comprises two check valves, 2 x 7.9 inch
head = 15.8 inch head (2 x 200 mm wc = 400 mm wc).
You use a mixture of water and 40% of propylene glycol as a solar fluid.
The installation height between the collector and the storage tank is ~33 ft (10 m).
Installation height in ft
Temperature difference storage tank/collector in °R
Result:
The check valves prevent gravity circulation up to a temperature difference of about 112 °R (~62 K). If the
temperature difference between the collector and the tank is larger, the difference in density of the solar fluid
will be so large, that the check valves are pushed open.
The density of the solar fluid decreases with rising temperature. In high installations with large temperature
differences, the difference in density will cause gravity circulation. This circulation can cool down the storage
tank
*Solar fluid = mixture of water and 40% glycol