Viessmann Vitomax HS M73 Training manual

Operating and service instructions
for contractors
Viesmann
Vitomax HS
Type M73
Type M75
Type M93
Type M95
High pressure steam boiler
VITOMAX HS
5837984 GB 1/2019 Please keep safe.

2
Please follow these safety instructions closely to
prevent accidents and material losses.
Safety instructions explained
Danger
This symbol warns against the risk of injury.
!Please note
This symbol warns against the risk of material
losses and environmental pollution.
Note
Details identified by the word "Note" contain additional
information.
Target group
These instructions are exclusively intended for quali-
fied contractors.
■Work on gas installations may only be carried out by
a registered gas fitter.
■Work on electrical equipment may only be carried
out by a qualified electrician.
Regulations to be observed
■Pressure Equipment Directive
■Health and Safety at Work Act (BetrSichV) [Ger-
many] and extended technical rules for operational
safety (TRBS)
■Country-specific safety regulations for the installation
site
■National installation regulations
■Statutory regulations for the prevention of accidents
■Statutory regulations for environmental protection
■Codes of practice of the relevant trade associations
Safety instructions for working on the system
Commissioning
Note
Unpleasant odours may develop during commission-
ing. Ensure the installation room is well ventilated.
Before working on the system
■Close the fuel shut-off valve and secure against
unintentional reopening.
■Isolate the system from the power supply, e.g. by
removing the separate fuse or by means of a mains
isolator, and check that it is no longer 'live'.
■Safeguard the system against reconnection.
Hot surfaces
Danger
Hot surfaces can lead to burns. Never touch hot
surfaces, e.g.
■Steam pipes
■Hot water pipes
■Cleaning apertures and closures on the boiler
system
■Boiler doors, as well as components behind
the doors
Observe occupational safety. Wear protective
clothing where necessary.
Electrostatic discharge
!Please note
Electronic assemblies can be damaged by elec-
trostatic discharge.
Prior to commencing work, touch earthed
objects such as heating or water pipes to dis-
charge static loads.
Repair work
!Please note
Repairing components that fulfil a safety func-
tion can compromise the safe operation of the
system.
Replace faulty components only with genuine
Viessmann spare parts.
Safety instructions
Safety instructions
5837984

3
Auxiliary components, spare and wearing parts
!Please note
Spare and wearing parts that have not been tes-
ted together with the system can compromise its
function. Installing non-authorised components
and making non-approved modifications or con-
versions can compromise safety and may inva-
lidate our warranty.
For replacements, use only original spare parts
supplied or approved by Viessmann.
Dismantling and disposal
When dismantling and disposing of thermal insulation
materials and gaskets on the gas side, observe the
applicable safety regulations.
The product and its components must be disposed of
according to local environmental regulations.
This applies in particular to the disposal of thermal
insulation materials and gaskets/seals on the gas side.
Safety instructions for operating the system
General
The materials included in the product pose no threat to
health during operation.
If you notice oil leaks or the smell of gas
Danger
Escaping fuel can lead to explosions which may
result in very serious injuries.
■Do not smoke. Prevent naked flames and
sparks. Never switch lights or electrical appli-
ances on or off.
■Close the quick-acting fuel valve and shut-off
valve.
■Ventilate the boiler house.
■Evacuate any people from the danger zone.
■Notify your gas or electricity supply utility from
outside the building.
■Have the power supply to the building shut off
from a safe place (outside the building).
If you smell flue gas
Danger
Flue gas can lead to life threatening poisoning.
■Shut down the system.
■Ventilate the installation site.
Draining hot water
!Please note
The blow-down and TDS water from boiler sys-
tems can reach temperatures of over 100 °C.
Before draining water into the sewage system,
allow it to cool to a temperature of < 35 °C. If
necessary, consult the local water board.
Draining condensate from the flue gas side
!Please note
When starting up the boiler system, or under
certain operating conditions, condensate may
build up in the flue passes, the flue gas collector
and the downstream flues, including the chim-
ney.
The condensate must be drained away safely by
means of suitable installation measures put in
place by the system installer.
Subject to the regulations in the country concerned,
this condensate may need to be neutralised. In such
cases, consult the local water board or the body
responsible for issuing permits.
General information
Shut down the boiler immediately if there is any
safety-related damage.
Observe safety-related instructions.
After an accident, the condition of the system must not
be changed before the investigation takes place,
unless necessary in order to rescue people or prevent
further damage.
Only authorised personnel are permitted to enter the
boiler house.
Keep the boiler house clean at all times.
Do not store anything in the boiler house.
Keep exits clear.
Never use the boiler house or system components as
a drying area.
The operating personnel must log the following:
■Settings
■Readings
■Faults
■Replacement of spare parts
■Repairs
Any defects must be dealt with immediately by trained
personnel, e.g.:
■Abnormalities on weld seams
■Leaks
■Heavy corrosion
■Faulty instrument displays
■Noise in the boiler
Safety instructions
Safety instructions (cont.)
5837984

4
Faults and defects that cannot be remedied locally
must be reported to the manufacturer. Protect all boiler
parts and control equipment from rain, water leaks and
expelled steam.
Safety instructions
Safety instructions (cont.)
5837984

5
1. Information Symbols ................................................................................................. 7
Note ....................................................................................................... 7
Designation of boiler types .................................................................... 7
Intended use .......................................................................................... 8
Systems with operating temperatures > 110 °C ..................................... 8
2. Functions Installation overview .............................................................................. 9
Description of selected components in a steam boiler system .............. 10
■Level electrodes qP to qW ................................................................... 10
■Safety valve wP ................................................................................... 11
■Air vent shut-off valve wQ (optional) .................................................... 11
■Steam shut-off valve wW ...................................................................... 11
■Blow-down wT and wZ ......................................................................... 12
■TDS unit wU and wI ............................................................................ 12
■Water level indicator rP ...................................................................... 12
■Pressure monitoring unit rQ to rR ...................................................... 13
■Sample cooler rZ ............................................................................... 14
3. Shutdown and preserva-
tion
Shutdown ............................................................................................... 15
■Steps to shut down the boiler ............................................................. 15
■Brief interruption in operation ≤ 3 days ............................................... 15
■Interruption in operation > 3 days ....................................................... 16
Information on maintenance .................................................................. 18
■Preventing excessive flue gas temperatures ...................................... 18
4. Water quality Standard values for water quality .......................................................... 19
Raw water .............................................................................................. 19
Top-up water .......................................................................................... 19
Condensate return ................................................................................. 19
Water treatment system ......................................................................... 19
Saline boiler feedwater requirements .................................................... 20
■Organic substances ............................................................................ 20
■Conditioning ........................................................................................ 21
■Sampling of water and steam ............................................................. 23
■Sample analysis ................................................................................. 23
■Test equipment and standardised analysis procedures ...................... 23
5. Commissioning Recommendation for commissioning ..................................................... 25
Preparations for commissioning ............................................................ 25
Commissioning sequence ...................................................................... 25
■Commissioning the control panel ....................................................... 25
■Commissioning the feedwater pumps ................................................ 26
■Filling the boiler with feedwater .......................................................... 26
■Adjusting the water level control ......................................................... 26
■Checking the water level limiter .......................................................... 26
■Commissioning the burner .................................................................. 27
■Function check of the safety pressure limiter ..................................... 27
■Safety valve function check ................................................................ 27
■TDS controller adjustment .................................................................. 28
■Checking the closures on the water side ............................................ 28
Commissioning following boiler idle time ............................................... 28
Boilout .................................................................................................... 28
Report .................................................................................................... 28
Instructions ............................................................................................ 28
6. Monitoring Recommendation for monitoring ............................................................ 29
■Testing intervals .................................................................................. 29
Operator's log ........................................................................................ 29
What to do in the event of operating faults ............................................ 29
Index
Index
5837984

6
7. Repairs and inspection Maintenance .......................................................................................... 31
■General requirements ......................................................................... 31
■Working on the boiler system ............................................................. 31
Inspection .............................................................................................. 31
■Safe inspection of the steam boiler .................................................... 31
■Inspections ......................................................................................... 32
8. Commissioning, inspec-
tion, maintenance
Steps - commissioning, inspection and maintenance ............................ 33
9. Troubleshooting Diagnosis ............................................................................................... 51
10. Wearing parts Wearing parts and gaskets .................................................................... 52
■Order forms ........................................................................................ 52
11. Checklist Recommendations for operation, maintenance and testing in accord-
ance with EN 12953-6 ........................................................................... 55
■Checklist for boiler system: Steam boiler ........................................... 55
Suggested tests and test intervals ......................................................... 56
12. Appendix Steam and hot water boilers .................................................................. 57
■Inspection checklist ............................................................................ 57
Water treatment system ......................................................................... 59
■Inspection checklist ............................................................................ 59
13. Commissioning/service
reports
Records of commissioning, inspection and maintenance ...................... 61
14. Keyword index ................................................................................................................ 62
Index
Index (cont.)
5837984

7
Symbol Meaning
Reference to other document containing
further information
1.
Step in a diagram:
The numbers correspond to the order in
which the steps are carried out.
Warning of material losses and environ-
mental pollution
Live electrical area
Pay particular attention.
■Component must audibly click into place.
or
■Acoustic signal
■Fit new component.
or
■In conjunction with a tool: Clean the sur-
face.
Dispose of component correctly.
Dispose of component at a suitable collec-
tion point. Do not dispose of component in
domestic waste.
The steps in connection with commissioning, inspec-
tion and maintenance are found in the "Commission-
ing, inspection and maintenance" section and identified
as follows:
Symbol Meaning
Steps required during commissioning
Not required during commissioning
Steps required during inspection
Not required during inspection
Steps required during maintenance
Not required during maintenance
Note
All diagrams in this document are schematic, illustra-
tive examples.
Designation of boiler types
With the boiler type, the respective stage of develop-
ment is indicated in capital letters.
Example M93B: Boiler type M93 version B
Information
Symbols
5837984
Information

8
The appliance is intended solely for installation and
operation in sealed unvented heating systems, with
due attention paid to the associated installation, serv-
ice and operating instructions. The appliance is inten-
ded exclusively for steam generation and for heating
water in accordance with EN 12953 and AGFW data-
sheet FW510 (VdTÜV datasheet TCh 1466).
Commercial or industrial use for a purpose other than
steam generation or the heating of water shall be
deemed inappropriate.
All other use is deemed inappropriate. Any resulting
losses are excluded from the manufacturer's liability.
Any usage beyond this must be approved by the man-
ufacturer in each individual case.
Intended use presupposes that a permanent installa-
tion in conjunction with permissible components
designed for this purpose has been carried out.
Intended use also includes adherence to maintenance
and inspection intervals.
Systems with operating temperatures > 110 °C
Category IV boiler systems compliant with Pressure Equipment Directive
Requirements for commissioning
■System installation has official approval.
■The system has been checked by an expert author-
ity.
■Commissioning of the control system is carried out
by a qualified organisation.
Requirements for operators
Only qualified personnel may operate, supervise and
service the system.
Requirements for operation without supervision
■Boiler system is equipped in accordance with EN
12953, Part 6.
■The system has received official approval for opera-
tion.
Checking system operation
Scope checks should be determined in accordance
with EN 12953-6
Danger
The surfaces of steam boilers and hot water
boilers and other areas of the system are poten-
tially hot. Risk of injury!
Always wear protection when touching the rele-
vant areas during operation.
Information
Intended use
5837984
Information

9
A
Z
O
C
rR
1
rZ
Z
AO
C
6 2 wTwZ
rT
4
3wP
wUwI
wWwQqQqW
rE
qPqW
rW rQ
rR
qT
wR
wE
rP
Fig. 1 Example installation diagram. Standard deliv-
ery may vary subject to order.
Note
CE-approved boiler with accessories fitted on site.
Standard delivery may vary subject to order.
1Boiler control platform with conductor (optional)
2Control panel (see separate documentation)
3Integral ECO (subject to boiler size) (optional)
4Connection line ECO - boiler (optional)
6Burner
qP Level electrode (WLC: Water level controller)
qQ Level electrode (HWL: Highest water level)
qW Level electrode (LWL: Lowest water level)
qT Conductivity electrode
wP Safety valve (number is country-specific)
wQ Air vent shut-off valve (optional)
wW Steam shut-off valve
wE Feedwater shut-off valve
wR Feedwater check valve
wT Blow-down shut-off valve
wZ Blow-down valve
wU Desalination shut-off valve
wI Desalination control valve
rP Water level indicator
rQ Pressure gauge
rW Maximum pressure limiter
rE Pressure transducer
rR Straight-through shut-off valve with cap (optional)
rT Temperature indicator for feedwater
rZ Sample cooler
Note
Illustration of fitting assembly rQ to rR, applies to mod-
ulating operation. For stepped operation, provide the
required number of pressure regulators in place of the
pressure transducer.
Functions
Installation overview
5837984
Functions

10
Detailed information
Manufacturer's documents for the individual
components
Level electrodes qP to qW
Permanently modulating water level control qP
Level electrode for continual and load-dependent
steam boiler filling
Function Operation Operating information
Continual water level control comprising:
■Level electrode
■Level controller
Water level differs from set
value.
The controller issues pulse to
feedwater control valve or varia-
ble speed pump.
Continual control of the boiler water level via a
feedwater control valve or variable speed pump
The filling of the steam boiler is
continual and load-dependent.
Tab. 1
Maximum water level (HW electrode qQ)
Level electrode to safeguard against overfilling
Function Operating condition Operating information
Self-monitoring overfill
protection comprising:
■Level electrode
■Evaluation device
Standard
water level
Electrode is not immersed in conducting boiler water.
Feedwater pump operation enabled.
Feedwater pump operates.
The filling of the steam boiler is continual and load-dependent.
High
water level
Electrode is immersed in conducting boiler water. Registers a
high resistance.
The feedwater pump is shut down via the pump relay.
Feedwater supply to the steam boiler interrupted.
The level drops again Feedwater pump starts automatically, dependent on demand.
Tab. 2
Additional HW electrode for up to 72 h operation
without continuous supervision according to
TRD 604
According to EN 12953-6, for a system with up to 72 h
operation without continuous supervision, this function
can also be performed by level electrode qP.
Note
Observe country-specific regulations.
Functions
Description of selected components in a steam boiler system
5837984
Functions

11
Lowest water level (NW electrode/low water level LWL qW)
Level electrode to safeguard against water shortage
Function Operating condition Operating information
Self-monitoring low
water indicator com-
prising:
■2 level electrodes
■Evaluation devices
Standard
water level
Burner operation enabled.
Safety chain closed.
Electrode is immersed in conducting boiler water. Registers
low resistance.
Too low
water level
Electrode is not immersed in conducting boiler water. Regis-
ters a high resistance.
Safety chain and burner operation constantly interrupted.
Min. boiler water capaci-
ty reached
Re-enable safety chain.
Burner block lifted.
Tab. 3
Safety valve wP
Function
■Physical protection of the steam boiler against pres-
sures in excess of the max. permissible operating
pressure PS
■Valve response pressure = permissible steam boiler
operating pressure
■Valve discharge rating ≥ max. steam output (steam
boiler)
■Maximum pressure increase until the SIV opens
completely (at maximum discharge) = PS + 10 %
■Closing pressure is PS - 10 %
Testing/checks Operating information
Operating checks at regular intervals or in accordance with country-
specific regulations
Vent the lever briefly - do not release the
lever (see manufacturer's operating in-
structions).
Regular checking by an authorised contractor or test body Never remove the lead seal.
Tab. 4
Air vent shut-off valve wQ (optional)
Function Operation Operating information
Venting the steam boiler during filling
or after a new system start at atmos-
pheric pressure
Open the valve during the
heating process. As soon as
you see steam emerging,
close the valve again.
Discharge hot air/steam safely.
Tab. 5
Danger
Hot air/steam can cause severe burns.
Discharge hot air/steam safely. Observe safety
regulations.
Steam shut-off valve wW
Function Operation Operating information
Main steam boiler shut-off to the
steam supply
Releasing steam or isolating
the steam boiler
Open slowly to avoid steam hammer.
Tab. 6
Functions
Description of selected components in a steam… (cont.)
5837984
Functions

12
Blow-down wT and wZ
Function: Periodic removal of deposits from the boiler
Operation Operating information
Regular automatic blow-down via au-
tomated programs
Program switch opens the blow-down valve via the control valve. Briefly
drain off the boiler water. The resulting suction removes the sludge from
the steam boiler. Manual activation possible at any time.
Observe country-specific regulations
concerning regular manual blow-
down.
Push the locking lever of the blow-down valve to the side.
Push down on the activating lever of the blow-down valve for 2 to 3 sec-
onds.
Tab. 7
Danger
A lever that kicks back may cause injury.
Do not release the lever.
TDS unit wU and wI
Function
■Continual checking and regulation of the salt content
through temperature-compensated conductivity elec-
trode
■Desalination via TDS valve
■Valve operates within specified limits
Operation Operating condition
Conductivity Falling Flow rate is reduced.
Exceeds the set value Valve is opened further.
Exceeds the highest value Safety chain is interrupted.
Burner operation is interrupted.
Tab. 8
Water level indicator rP
Function: Visual and direct water level indication
Operation Operating information
Visual water level check Valve on the steam and water side: Shut-off device is
"OPEN"
Flushing valve: Shut-off device is "CLOSED"
When there are no operating personnel present Keep valves "CLOSED"
Functions
Description of selected components in a steam… (cont.)
5837984
Functions

13
Operation Operating information
Regular operating checks. Observe country-specific
regulations.
Close the valve on the water and steam side
Open flushing valve, drain and check the valves for tight-
ness
Open the valve on the water side; check for discharge
noise
Close valve on the water side
Open the valve on the steam side; check for discharge
noise
Leave the valve on the steam side open
Close the flushing valve
Open valve on the water side
The water column rises quickly to the correct level. If the water column rises slowly, check if there is a block-
age
Tab. 9
Pressure monitoring unit rQ to rR
The pressure monitoring unit is directly connected to
the steam boiler via the fitting assembly.
Component Function Operating information
Pressure gauge rQ Operating pressure indica-
tor
Regular operating check. Observe country-specific reg-
ulations.
Pressure limiter rW If maximum pressure is ex-
ceeded: Protect the steam
boiler against positive pres-
sure
Checking with a calibrated test pressure gauge by an
authorised contractor or test body
Safety chain interrupted by opening a contact in the
pressure limiter.
Burner operation is interrupted.
■Safety chain is reset by pressing the button on the
control panel and the pressure limiter.
■Reduce boiler pressure via air vent valve or main
steam valve: Approx. 1 bar below the switching point
of the max. pressure limiter
■Reset the max. pressure limiter.
■Burner starts again.
Pressure transducer rE Load-dependent regulation
of the boiler combustion
subject to the operating
pressure
Straight-through shut-off
valve with cap rR
Enables the replacement of
faulty components
Only by authorised contractors
Tab. 10
Functions
Description of selected components in a steam… (cont.)
5837984
Functions

14
Sample cooler rZ
Function Operating information
Removal of water sam-
ples to carry out compara-
tive tests
Measure and document the following values in the operator's log:
■pH value
■Residual hardness
■p value (value to determine the free alkalinity)
■m value (value to determine the entire alkalinity)
■Phosphate
■Sulphide
Measure and document additional values according to the country-specific regula-
tions.
Tab. 11
Functions
Description of selected components in a steam… (cont.)
5837984
Functions

15
Shutdown means shutting down the system via the cir-
cuit breaker at the control panel. The duration of the
shutdown determines the preservation measures
described in this chapter.
A short-term shutdown is not recommended, as every
start-up process subjects the boiler to additional
stresses. For up to 72 hours, for example over a week-
end, the boiler should be left to continue operating.
If pressure can be reduced via an additional pressure
regulator or via the programmable logic controller
(PLC), then the boiler pressure can be reduced by up
to 2 bar below operating pressure. Close the steam
valve downstream of the thermal water treatment
(TWT) outlet.
Note
Keep the TWT and boiler under pressure when taking
the system briefly out of use.
Steps to shut down the boiler
1. Shut down combustion system and close the fuel
valve.
2. Feed the boiler up to the controlled water level.
3. Close the steam and feedwater valve (see notes on
TWT).
4. Switch the circuit breaker on the control panel to
"OFF".
What preservation is for
A depressurised boiler system is at risk from idle-time
corrosion. Preservation prevents such corrosion. Pres-
ervation measures are carried out on surfaces on the
flue gas and water side of boiler systems. The type of
preservation depends on the type and duration of the
interruption in operation.
Type of preservation Effect
Wet preservation Keeps oxygen away from the boiler system
Dry preservation Keeps moisture in the boiler system to a minimum
Tab. 12
Interruption in operation
Duration Recommendation
≤ 3 days Maintain the positive pressure in the boil-
er system incl. all boiler-related equip-
ment (thermal water treatment, etc.).
> 3 days Select type of preservation.
Tab. 13
Note
If using chemicals other than those stated here, please
consult the manufacturers of the chemicals with regard
to the procedures to be used.
Basic rule:
VdTÜV datasheet TC 1465 "Preserving the water side
of steam boilers"
Brief interruption in operation ≤ 3 days
Treatment for preservation of the water side
Operating
condition
Measures
The boiler is
switched off.
Add oxygen binder to the feedwater 1
hour before switching off. Dosing: 2
to 3 times the standard dose
The boiler re-
mains on.
Maintain the boiler system pressure
and temperature.
Tab. 14
Preservation with ammonia or nitrogen
■Both preservation methods require extensive techni-
cal effort.
■Consult the chemical manufacturers before use.
■The operator must compile system-specific operating
instructions.
Treating the flue gas side
■Keep heating surfaces dry.
■Heavy contamination causes moisture and must be
removed.
Shutdown and preservation
Shutdown
5837984
Operation

16
Interruption in operation > 3 days
Treatment for preservation of the water side
Dry preservation
Note
Restarting the system quickly is not possible.
Applications:
■Prolonged boiler idle periods
■Risk of frost*1
1. Drain the steam boiler.
!Please note
Draining hot water into the sewage system
causes environmental damage.
Therefore cool the water to < 35 °C before-
hand. If necessary, collect it in containers.
2. Flush the steam boiler again on the water side,
using high salt content flushing water
(> 5000 µS/cm).
3. Open the water closures.
Note
Components such as ECO must be dried out sepa-
rately.
4. Dry the boiler system thoroughly.
5. Place desiccant (silica gel) in the boiler system in
accordance with the manufacturer's instructions.
Note
Ensure that the desiccant does not come into
direct contact with the boiler material.
6. Close the boiler system.
7. Check the effectiveness of the desiccant regularly.
Wet preservation
1. Fill the boiler system (incl. ECO, if installed) up to
the highest possible level with treated feedwater.
2. Note
To prevent oxygen corrosion, mix oxygen binder,
e.g. sodium sulphite, into the boiler water in
accordance with the manufacturer's instructions.
Mix the oxygen binder thoroughly with the boiler
water by means of thermal or mechanical circula-
tion.
3. Check the concentration of the oxygen binder at
regular intervals and at least every month. If nec-
essary, add more oxygen binder.
Preservation with sodium sulphite
1. Add the sodium sulphite in soluble form to the
completely drained steam boiler via the feedwater
pump.
Note
When carrying out the preservation, keep all
valves/fittings closed.
2. Fill the steam boiler completely. Also fill the ECO (if
installed).
3. Set pH value to between 11 and 12.
4. Circulate preservation solution weekly.
5. Circulation
Initially, check the sulphide excess frequently, then
at least monthly. If the concentration falls below the
specified standard values, recirculate and top up if
necessary.
6. For unvented, cold treated water: Add an additional
80 g desiccated or 160 g crystallised sodium sul-
phite per 1 m3.
*1 See the "Using antifreeze in boilers" chapter in the technical guide
Shutdown and preservation
Shutdown (cont.)
5837984
Operation

17
Sodium sulphite excess
Type of fill water for steam
boilers
Idle time Sodium sulphite concentra-
tion Na2So3 in preserving
solution
Additional sodium sulphite
Desiccated Crystallised
mg/l g/m3g/m3
Low salt content, fully desali-
nated or condensate
1 week 20 - 50 20 - 50 40 - 100
1 month 100 - 200 100 - 200 200 - 400
> 1 month 200 - 500 200 - 500 500 - 1000
Saline, e.g. softened water or
boiler water
1 week 40 - 100 40 - 100 80 - 100
> 1 week 400 - 1000 400 - 1000 800 - 2000
Tab. 15
!Please note
Film forming amines can cause damage to the
boiler.
Do not use film forming amines.
Applicable regulations:
■For draining preserving solutions:
Observe conditions for draining waste water into
sewer systems or the main discharge system.
■For the use of preserving agents:
Observe working instructions and safety datasheets
supplied by the product manufacturer.
Preservation through physical-technical measures
The following physical-technical procedures can also
be used for preservation:
■Maintain a positive steam pressure in the steam or
hot water boiler
■Flow preservation of steam boilers
Preserving individual areas of a multi boiler sys-
tem
The relevant individual boilers are kept at temperature
by pumping boiler water from the rest of the boiler sys-
tem through them.
Corrosion protection on the entire boiler shell
A fully filled boiler shell is maintained at a pressure of
0.1 to 0.2 bar using nitrogen, specifically nitrogen 5.0.
!Please note
Frost may cause damage to the boiler.
Do not use wet preservation if there is a risk of
frost!*1
!Please note
Do not use layer-forming monoamines.
The use of film-forming polyamines must be
agreed with and approved by the boiler manu-
facturer.
Recommendation
Agree the steps for the preservation of the water side
with the manufacturer of the preserving agent.
Applicable regulations
Draining preserving solutions
■Conditions for draining waste water into sewer sys-
tems or the main discharge system
Use of preserving agents
■Working instructions and safety datasheets supplied
by the product manufacturer
Treating the flue gas side
1. Clean the heating surfaces on the flue gas side.
Maintain the alkaline balance of the water used for
cleaning at pH 8 to 9, or, in the case of ammonia,
pH 10.
2. Dry the heating surfaces on the flue gas side (allow
normal air flow).
3. Accelerate the ventilation process by means of a
fan heater. If necessary, open the flue gas shut-off
dampers, then close them again.
4. Spray preserving oil, e.g. graphite or varnish, onto
the flame tube walls and hot gas flues, or apply it
with a brush.
5. Keep the boiler door(s) open. Keep the boiler sur-
faces dry during idle periods.
6. Apply a desiccant (silica gel).
7. Use a dryer with a fan.
*1 See the "Using antifreeze in boilers" chapter in the technical guide
Shutdown and preservation
Shutdown (cont.)
5837984
Operation

18
Recommendation for areas with high relative
humidity
Do not use dry preservation in areas with high relative
humidity (in the tropics, near the sea) due to the spe-
cial installation conditions that prevail in these areas.
Detailed information
■Operating instructions for preservation on the
water and hot gas side
■Datasheets of the VdTÜV, no. MB TECH
1466, dated 2014-01, and the VGB, no.
R116H, dated 2009
Information on maintenance
Correct maintenance ensures trouble-free, efficient
and environmentally responsible system operation:
■Observe the specified maintenance intervals
■Only use authorised companies:
–Viessmann Industrial Service (see contact details)
–Other authorised contractors
Preventing excessive flue gas temperatures
Excessively high flue gas temperatures make the
system less efficient
Cause of fault Remedy
Altered burner
adjustment
Adjust the burner correctly
Contaminated
boiler system
Clean the boiler system
Tab. 16
Recommendation
Continuous monitoring of the flue gas temperature
using a flue gas thermometer.
Shutdown and preservation
Shutdown (cont.)
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Advantages of complying with the guidelines
■Prolongs boiler service life.
■Reduces repair costs.
Advantages of using a chemical water treatment
■The specified standard values and water conditions
are observed.
■No additional corrosion protection is required
–if the system is designed as a hot water heating
system sealed against corrosion and
–If all other instructions stated in the "Standard val-
ues for water quality" chapter are complied with.
Recommendation
Use a chemical water treatment system in the boiler
system.
Please contact Viessmann for a quotation.
Note
Observation of the following requirements is a neces-
sary condition for safeguarding your warranty rights.
The warranty excludes damage due to corrosion and
scaling. Prevention of damage due to scaling.
Raw water
Not usually suitable as boiler feedwater in its delivered
state and must be treated before use. The type of
boiler feedwater treatment depends on the raw water
quality. As the water quality may change, regular
checks are required.
Top-up water
A suitable water meter should be installed in the water
supply pipe for treating the boiler feedwater. This
records the amount of top-up water added to the recy-
cled condensate. It will also indirectly monitor the
amount of steam removal.
Condensate return
Where possible, feed the condensate back to the feed-
water tank without loss. To fulfil the boiler feedwater
requirements (Tab. 15), the condensate may need to
be treated.
Water treatment system
Depending on raw water quality and amount of top-up
water, the raw water and top-up water must be adjus-
ted to fulfil the boiler water requirements (Tab. 17 & 18
page 20).
In order to do this, a suitable chemical and thermal
water treatment system must be installed.
Recommendation
Contact Viessmann for a quotation for a water treat-
ment system.
If required, there must be an option to add oxygen
binders to the feedwater tank or its inlet pipe (residual
hardness stabilisers, alkalising agents and phos-
phates).
Depending on the operating mode (24 h or 72 h) and
country-specific regulations, suitable test devices are
used to ensure compliance with the requirements.
Entry in the operator's log
■Measurements
■Amounts of top-up water
■Chemical consumption
■Required maintenance
The operator's log can be used to simulate the operat-
ing conditions at any time.
Water quality
Standard values for water quality
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Permissible operating pressure bar 0.5 ≤ PS ≤ 20 PS > 20
General requirements Colourless, clear, free of undissolved substances
pH value at 25 °C > 9
Conductivity at 25 °C µS/cm Only standard values applicable to boiler water
Total alkaline earths (Ca2+ + Mg2+)mmol/ l < 0.01
Oxygen (O2) mg/l < 0.05 < 0.02
Bound carbon dioxide (CO2) mg/l < 25
Iron (Fe), total mg/l < 0.2 < 0.1
Copper (Cu), total mg/l < 0.05 < 0.01
Oxidability (Mn VII → Mn II) as
KMnO4mg/l < 10
Oil, grease mg/l < 1
Tab. 17
Organic substances
In general, organic substances are mixtures of differ-
ent compounds. The constitution of such mixtures and
the characteristics of their components when subjected
to boiler operating conditions are hard to predict.
Organic substances may break down into carbonic
acid or other acid products. These increase conductiv-
ity and cause corrosion and deposits.
They can also lead to the formation of foam and
deposits, which must be kept to a minimum. The TOC
content (Total Organic Carbon) should also be kept to
a minimum.
Boiler water requirements
Feedwater conductivity > 30 µS/cm ≤ 30 µS/cm
Permissible operating pressure bar 0.5 ≤ PS ≤ 20 PS > 20 PS > 0.5
General requirements Colourless, clear, free of undissolved substances
pH value at 25 °C 10.5 to 12 10.5 to 11.8 10 to 11*2*3
Acid capacity (KS 8.2) mmol/l 1 to 12 1 to 10 0.1 to 1.0*2
Conductivity at 25 °C µS/cm < 6000 See Fig. 2 < 1500
Phosphate (PO4) mg/l 10 to 20 6 to 15
Silicic acid (SiO4)*4 mg/l Pressure-dependent, see Fig. 2 & 3
Tab. 18
Detailed information
EN 12953-10
*2 Demineralised water with mixed bed quality (conductivity < 0.2 µS/cm) may be used without a phosphate injection. As an
alternative, AVT operation may be applied. Conditioning with volatile alkalising agents: pH value of feedwater pH ≥ 9.2 and
pH value of boiler water pH ≥ 8.0. In such cases, the conductivity downstream of a severely acidic cation exchanger must
be < 5 µS/cm.
*3 Standard pH value setting: Injection of Na3PO4, additional injection of Na OH (if the pH value < 10)
*4 If allowance is made for all other values, higher PO4 concentrations are permissible when using phosphate. This applies,
for example, to compensated or coordinated phosphate treatment (see section "Conditioning").
Water quality
Saline boiler feedwater requirements
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