KOB KPT 1250 Series User manual

Installation and
Operating Instructions
for use by engineers and heating contractors
5603 882 - 01 07/2014
Read and save these instructions
for future reference.
KPT 390 to KPT 1250 Series
Wood-fired Boiler
Max. output: 390 to 1250 kW (1331 to 4266 MBH)
Min. output: 98 to 370 kW (334 to 1263 MBH)
Pyrotecr
Product may not be exactly as shown
Please file in Service Binder
IMPORTANT
IMPORTANT
Please ensure that these instructions are
read and understood before commencing
installation and start-up. Failure to comply
with these Installation Instructions will
render all warranties null and void.
Working on the equipment
The installation, adjustment, service and
maintenance of this product must be
performed by a licensed professional heating
contractor, who is qualified and
experienced in the installation, service
and maintenance of hot water heating
boilers. There are no user serviceable
parts on the boiler or control.
Ensure main power supply to equipment,
the heating system and all external
controls has been deactivated.
Take precautions in all instances to avoid
accidental activation of power during
service work.
Improper installation, service or
maintenance can cause product/property
damage, severe personal injury, and/or
loss of life.
H

2
5603 882 - 01
Pyrotec Installation & Operating
Safety, Installation and Warranty Requirements
WARNING
Installers must follow local regulations with respect
to installation of carbon monoxide detectors. Follow
manufacturer’s maintenance schedule of the boiler
contained in the ”Service and Maintenance Instructions”.
Please ensure that these instructions are read and understood before commencing installation and service. 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).
Product documentation
Read all applicable documentation before commencing
installation. Store documentation near boiler in a
readily accessible location for reference in the future
by service personnel.
For a listing of applicable literature,
please see section entitled “Important
Regulatory and Safety Requirements”.
Warranty
Information contained in this and
related product documentation must
be read and followed. Failure to do
so renders the warranty null and void.
Licensed professional heating contractor
The installation, adjustment, service and maintenance
of this equipment must be performed by a licensed
professional heating contractor.
Please see section entitled
“Important Regulatory and Installation
Requirements”.
Contaminated air
Air contaminated by chemicals can cause by-products
in the combustion process, which are poisonous to
inhabitants and destructive to Viessmann equipment.
For a listing of chemicals which
cannot be stored in or near the
boiler room, please see subsection
entitled “Mechanical Room”.
Advice 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. Refer to the Service
and Maintenance Instructions for details.
Carbon monoxide
Improper installation, adjustment, service and/or
maintenance can cause flue products to flow into
living space. Flue products contain poisonous carbon
monoxide gas.
For information pertaining to the proper
installation, adjustment, service and
maintenance of this equipment to avoid
formation of carbon monoxide, refer
to the “Safety” section.
Fresh air
This equipment requires fresh air for
safe operation and must be installed
ensuring provisions for adequate
combustion and ventilation air exist.
For information pertaining to the
fresh air requirements of this product,
refer to the “Combustion Air Supply”
section.
Equipment venting
Never operate boiler without an installed venting
system. An improper venting system can cause
carbon monoxide poisoning.
For information pertaining to
venting and chimney requirements,
refer to the “Safety” section. All
products of combustion must be
safely vented to the outdoors.
Introduction

3
5603 882 - 01
Pyrotec Installation & Operating
About These Instructions
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.
CAUTION
Cautions draw your attention to the presence of potential
hazards or important product information.
WARNING
Warnings draw your attention to the presence of potential
hazards or important product information.

IMPORTANT
Indicates an imminently hazardous situation which,
if not avoided, could result in death, serious injury or
substantial product/property damage.
Indicates an imminently hazardous situation which,
if not avoided, may result in minor injury or product /
property damage.
Helpful hints for installation, operation or maintenance
which pertain to the product.
This symbol indicates to note additional information
This symbol indicates that other instructions must be
referenced.
Note: Viessmann Manufacturing Company Inc. reserves
the right to make product changes or updates
without notice and will not be held liable for
typographical errors or omissions in the product
literature.
Introduction

4
5603 882 - 01
Pyrotec Installation & Operating
Table of Contents
Introduction
General Information
Safety
Mechanical
Safety, Installation and Warranty Requirements..............2
About These Instructions..............................................3
Important Regulatory and Installation Requirements........6
Codes...................................................................6
Mechanical room...................................................6
Working on the equipment......................................6
Technical literature................................................6
Product Information.....................................................7
Boiler Description........................................................8
Transport and Installation.............................................9
Lifting...................................................................9
Delivery Condition.....................................................10
Standard delivery condition....................................10
Wood Fuel Requirements...........................................11
Allowed fuels......................................................11
Non-wood fuels....................................................12
Maximum water content.......................................12
Limitation super fines and dust............................12
Suitable fuel types for Pyrotec systems..................12
Content limits for non-combustable substances.......13
Other information.................................................13
Carbon Monoxide......................................................14
Hazardous Materials..................................................15
Fiberglass wool and ceramic fiber materials.............15
First aid measures...............................................15
Power Failure Provision..............................................16
Venting Requirements................................................16
Mechanical Room.....................................................17
Mechanical room conditions...............................18
Sources of combustion and ventilation
contaminants......................................................18
Combustion Air Supply..............................................19
Codes................................................................19
General..............................................................19
Confined spaces..................................................19
Unconfined spaces...............................................19
Louvers and grilles...............................................19
Technical Data.........................................................20
Boiler Dimensions......................................................21
Boiler Components....................................................22
Flue Gas Cyclone......................................................23
Recirculation System.................................................24
Safety Devices.........................................................26
Fire extinguishing water tank.................................26
Expansion...........................................................26
The boiler system with 3-way mixing valve.............26
Drain inspection port............................................26
Piping and Installation of Safety Devices......................28
Fire Protection..........................................................30
Power failure provision..........................................30
Protection against back-burn for the boiler plant.......30
Back-burn safeguard for the fuel supply system.......31
Automatic triggering system for fuel supply system.....31
Slide valve..........................................................31
Rotary valve........................................................31
Double rotary valve pressure compensation system...31
Down pipe..........................................................31
Fire protection for fuel storage space......................31
Page

5
5603 882 - 01
Pyrotec Installation & Operating Table of Contents
Mechanical (continued)
Electrical
Operation
Page
Fire Extinguishing System.........................................32
Assembly of the Fire Extinguishing System...................33
Negative Pressure Monitoring Assembly........................34
Control Panel...........................................................35
Mounting of control panel....................................35
Electrical connection............................................35
General safety instructions...................................35
Vitocontrol-C Pyrocontrol KPT..............................36
Electrical Components...............................................38
Fuel Transport and Extraction Systems........................40
Rotary valve........................................................40
In-feed auger.......................................................41
Pipe/trough conveyor auger...................................41
Pellet extraction auger..........................................42
Spring extraction system.......................................42
Horizontal extraction system..................................43
Walking floor auger...............................................44
Hydraulic unit......................................................44
Thermal Storage Tank...............................................45
Boiler Wiring.............................................................46
Commissioning......................................................47
Initial startup...................................................47
Filling the heating system..................................47
Fuel for the commissioning................................47
Commissioning and hand over............................47
Filling the Fuel Storage Unit....................................48
Horizontal extraction system and
spring extraction system....................................48
Pellet extraction auger.......................................48
By dumping.........................................................48
By blowing in......................................................48
Fixing malfunctions in the feed systems..................48
Excess Conditions.....................................................49
Excess temperature/power failure..........................49
Low water/excess water pressure.........................49
Pyrocontrol Control System........................................50
Export of operational data via Mod-bus Pyrocontrol..50
Touch screen, Screen 1-8....................................51
Screen 1, Object Indicator Light............................52
Screen 2, Alarm list.............................................53
Screen 3, Managing the user status.......................54
Screen 4, Adjusting settings and parameters...........55
Screen 7, Overview wood powered boiler...............56
Screen 8, Additional boilers...................................57
Pyrotec control system parameters ........................58
Pyrotec controller parameter reference
guide for the technician.........................................59
Operating Modes.......................................................62
Full load operation................................................63
Output control.....................................................63
Sustain...............................................................63
“Cycle for underfeed auger sustain” too high.........63
“Cycle for underfeed auger sustain” too low..........63
Standby..............................................................63
Transition in output..............................................63
Switching off......................................................63
Emergency operation.............................................63
Measurement operation.........................................63
Heating Up Manually.................................................64

6
5603 882 - 01
Pyrotec Installation & Operating
Important Regulatory and Installation Requirements
Take note of all symbols and notations intended to draw attention to potential hazards or important
product information. These include ”WARNING”, ”CAUTION”, and ”IMPORTANT”.
Codes
The installation of this unit shall be in accordance with
local codes. In the absence of local codes, use: B 365-01,
Installation Code for Solid-Fuel Burning Appliances and
Equipment.
All electrical wiring is to be done in accordance with the
latest edition of CSA C22.1 Part 1 and/or local codes. In
the U.S. use the National Electrical Code ANSI/NFPA 70
where required by the authority having jurisdiction.
Mechanical room
Ensure the mechanical room complies with the requirements
listed in this manual. See section entitled Mechanical Room.
Working on the equipment
The installation, adjustment, service, and maintenance
of this boiler must be done by a licensed professional
heating contractor who is qualified and experienced in
the installation, service, and maintenance of hot water
boilers. There are no user serviceable parts on the boiler,
or control.
Ensure main power supply to equipment, the heating
system, and all external controls have been deactivated.
Take precautions to avoid accidental activation of power
during service work.
Technical literature
Literature applicable to all aspects of the Pyrotec wood-
fired boiler:
- Installation and Operating Instructions
- Service and Maintenance Instructions
- Field Wiring Diagram
Please carefully read this manual prior to attempting
installation. Any warranty is null and void if these
instructions are not followed.
For information regarding other Viessmann
System Technology componentry, please reference
documentation of the respective product.
We offer frequent installation and service seminars
to familiarize our partners with our products. Please
inquire.
The 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, etc.
Leave all literature at the installation site and advise
the system operator/ultimate owner where the
literature can be found. Contact Viessmann for
additional copies.
This product comes with several safety instruction
labels attached.
Do not remove!
Contact Viessmann immediately if replacement labels
are required.
General Information

7
5603 882 - 01
Pyrotec Installation & Operating General Information
Product Information
Viessmann solid-fuel boiler may only be installed and
serviced by trained personnel.
Steel wood-fired hot water heating boiler.
For operation primarily with modulating boiler water
temperatures in closed loop forced circulation hot water
heating systems. Under certain conditions, open loop
systems may also be considered. Contact Viessmann
for details. WARNING
Exposing the boiler to pressures and temperatures in
excess of those listed will result in damages and will
render the warranty null and void.
Maximum allowable working pressure (water)...30 or 60 psi
Maximum water temperature…..250° F (120° C) (closed loop)
Maximum boiler temperature………210° F (99° C) (open loop)
This boiler does not require a flow switch.
Note: “Pyrotec“ is an alternate / interchangeable trade
name with “Pyrtec”.
Codes
CSA B366.1-M91
Solid Fuel Fired Central Heating Appliances
CSA C.22.2#3-M88 (R2004)
Electrical Features of Fuel Burning Equipment
UL2523
Solid Fuel-Fired Hydronic Heating Appliances, Water
Heaters and Boilers
CSA B365-10
Installation Code for Solid Fuel Burning Appliances
and Equipment

8
5603 882 - 01
Pyrotec Installation & Operating
Boiler Description
Description
The PYROTEC Grate Firing System (patent no: EP 0 905
442 B1) was developed for automatic combustion of all dry
to moist wood fuels (remnant wood, pellets and forest wood
chips to max. W50, (see section “Wood Fuel Requirements”)
and combines the benefits of underfeed firing with the
benefits of grate firing.
The PYROTEC Grate Firing System is characterized by
highest efficiencies and perfect combustion in all load
stages. The PYROTEC Boiler Plant has been built to
ASME Sec. IV and has CRN for Canada. It is tested and
approved to the applicable CSA / UL safety standards.
Function:
- The solid, powerful and heat-resistant in-feed auger
moves the fuel over the burner trough into the
descending and moving grate zone. An electrical and
mechanical temperature sensor to operate the
thermal extinguishing valve are located on the in-feed
auger. Above the auger is the metering container with
a light barrier for setting the level of the fuel insulating
layer.
- The fuel is either ignited manually or automatically with
an automatic igniter (optional). The boiler features
a reliable burner trough, a descending grate and
a moving burn-out grate made from highly-refractory
cast steel [approx. bin. (12 mm)]. These items allow
to achieve excellent performance control and highest
safety against back-burn in conjunction with an automatic
de-ashing assembly with ash container (optional)
for the combustion chamber.
The solid, horizontally positioned and large-volume
combustion chamber door has been optimized in terms
of combustion, consists of a high-quality refractory
brick lining and has multiple layers of insulation for the
lowest possible surface temperatures. A variable speed
primary air blower provides preheated air to the
combustion grates in the combustion chamber door.
- In the upper part of the combustion chamber door, the
secondary air is blown into the gas space of the firing
system by variable speed blower via an encircling ring
with individually adjustable nozzles to achieve high
turbulence. This mixes the fuel gases with fresh
secondary air to achieve perfect combustion and very
low emissions. The combustion chamber door is
solidly constructed, air-cooled and very well insulated.
The combustion chamber door is equipped with solid
double-jointed hinges for easy maintenance. The heat
is transferred to the water in the horizontal heat
exchanger. The boiler is well insulated and highly
accessible through the heat exchanger door on the
front. A pneumatic cleaning system (optional) can be
installed at the insulated heat exchanger door.
- The flue gas exhaust blower has been specially
designed for wood burning boilers and quiet operation.
The spring-suspended motor has a solid, heat-resistant
design with a heat dissipation hub. The blower housing
on the intake can be mounted radial by 360° and has a
variable rotation speed and a round blow-out nozzle. It
is mounted directly on the boiler or on the flue gas
cyclone (optional).
General Information
Supplied with:
- Boiler with combustion chamber and pressure vessel/
heat exchanger including supply and return
temperature sensors and over pressure monitor
- Combustion chamber with burner trough, descending
grate, moving burn-out grate and light barriers for
ember monitoring
- In-feed auger including insulating layer, safety end
switch for maintenance lid, back-burn temperature
sensor, thermostatic valve for extinguishing assembly,
extinguisher water container with mounting bracket
- Flue gas exhaust blower including flue gas temperature
sensor and oxygen sensor
- Boiler cleaning tools for the combustion chamber
and heat exchanger
- Installation fittings including pressure relief valve, drain
valve, low water cut off, safety temperature limiter,
temperature and pressure gauges
- Control cabinet with integrated Pyrocontrol control
system
Customer supplied:
- Counter flanges for the boiler supply and return
- Piping to the 3-way mixing valve, boiler pump and
thermal storage tank
- Piping for the safety heat exchanger
- Wiring to the control panel
- Insulation for the flue gas re-circulation line, the flue
gas recirculation system is optional
Accessories for PYROTEC Grate Firing System:
- Flue gas cyclone 63 USG (240 L)
- Flue gas cyclone 211 USG (800 L)
- Automatic de-ashing assembly with ash container,
63 USG (240 L)
- Automatic de-ashing assembly with ash container,
211 USG (800 L)
- Pneumatic cleaning system
- Automatic igniter
- Set of displacement rods (for Pyrotec 720, 950 and
1250 only)
- Operating pressure 30 or 60 psi
- Two-stage in-feed auger
- Flue gas recirculation system
- Thermal safety flush valve
- Slide valve / Rotary valve
- Boiler pump and boiler mixing valve
- Pyrocontrol control system options:
- 5 sensor thermal storage tank management system
- External control module for field supplied extraction
system
- Output module / Input module
- Input module 0-10V
- ModBus
- BacNet gateway
- Visualization

9
5603 882 - 01
Pyrotec Installation & Operating
Transport and Installation
General Information
Precautions must be taken to avoid accidents and injury
during the transportation of the boiler.
Only hoist the boiler when it is entirely empty of water,
fuel and ash.
Lifting
The combustion chamber has four lifting lugs that must
be screwed in before lifting. Lifting gear can be attached to
these lifting lugs.
The pressure vessel of the PYROTEC has two lifting lugs
to which lifting gear may be attached.
A special crane (provided by the customer on site) is
required to lift the combustion chamber and the pressure
vessel.
Recommended minimum clearances to walls for
installation and maintenance work must be observed.
An anti-vibration boiler support should be provided if
anti-vibration measures are required.
IMPORTANT
ALifting lugs (screw in before lifting)
BLifting lugs (pressure vessel)
WARNING
Follow instructions for proper installation.
For wood-fired installations:
This wood-fired boiler must be installed in accordance
with local codes if any; if not, follow B365-10,
Installation Code for Solid-Fuel Burning Appliances
and Equipment.

10
5603 882 - 01
Pyrotec Installation & Operating
General Information
Measurements for the combustion chamber as standard delivery condition
Boiler model KPT390 KPT530 KPT720 KPT950 KPT1250
Minimum size
door (W x H)
59 in. x 59 in.
(1500 mm x
1500 mm)
63 in. x 69 in.
(1600 mm x
1750 mm)
63 in. x 69 in.
(1600 mm x
1750 mm)
74cin. x 73cin.
(1900 mm x
1850 mm)
74cin. x 78cin.
(1900 mm x
2000 mm)
Minimum ceiling
opening (W x H)
59 in. x 149 in.
(1500 mm x
3800 mm)
63 in. x 157bin.
(1600 mm x
4000 mm)
63 in. x 196cin.
(1600 mm x
5000 mm)
74cin. x 196cin.
(1900 mm x
5000 mm)
74cin. x 216bin.
(1900 mm x
5500 mm)
Delivery Condition
Measurements for the pressure vessel as standard delivery condition
Boiler model KPT390 KPT530 KPT720 KPT950 KPT1250
Minimum size
door (W x H)
59 in. x 59 in.
(1500 mm x
1500 mm)
63 in. x 69 in.
(1600 mm x 1750
mm)
63 in. x 69 in.
(1600 mm x
1750 mm)
74cin. x 73cin.
(1900 mm x
1850 mm)
74cin. x 78cin.
(1900 mm x
2000 mm)
Minimum ceiling
opening (W x H)
59 in. x 112ain.
(1500 mm x
2850 mm)
63 in. x 112ain.
(1600 mm x
2850 mm)
63 in. x 126 in.
(1600 mm x
3200 mm)
74cin. x 130 in.
(1900 mm x
3300 mm)
74cin. x 137cin.
(1900 mm x
3500 mm)
Standard delivery condition
The standard delivery condition of the Pyrotec boiler includes pre-assembled components as well as components
that need to be assembled by the contractor in the field.
Components that are attached to the boiler at time of delivery:
- Heat exchanger door is mounted to the heat exchanger
- Combustion chamber door is mounted to the combustion chamber
- Flue gas collector is attached to the heat exchanger
- Pneumatic cleaning system (optional) is attached to the heat exchanger door
Components that are not attached or installed to the boiler at time of delivery (scope of the contractor):
- The pressure vessel is not mounted to the combustion chamber
- Brickwork to connect the combustion chamber and the heat exchanger, bricks and mortar are included
- Electrical components which include temperature sensors, oxygen sensor, light barriers for the combustion chamber,
igniter, low water cut off, fixed high limit, negative pressure monitoring assembly and light barriers for
the complete extraction system
- All wiring to the control cabinet
- Installation fittings which include pressure relief valve, drain valve, temperature and pressure gauges
- Drive for the combustion chamber grate is detached
- De-ashing assembly with ash container (optional) and drive for the de-ashing system
- Air compressor (optional) and connection to the pneumatic cleaning system (optional)
- The flue gas exhaust blower is not attached to the flue gas collector
- Primary air blowers are not attached to the combustion chamber
- Secondary air blowers are not attached to the combustion chamber
- Re-circulation system (optional)
- Flue gas cyclone (optional) comes in two pieces
- The in-feed auger is detached from the combustion chamber
- Fire extinguishing system for the in-feed auger
- Slide valve (optional) or rotary valve (optional)
- All components of the extraction system (optional), welding for flanges and support legs required
- Glass fiber insulation between any auger connections

11
5603 882 - 01
Pyrotec Installation & Operating
Wood Fuel Requirements
Allowed fuels
- Forest wood and plantation wood (complete untreated trees and trunk wood):
Mature wood from trunks and branches, untreated, chopped to chips
- Compressed wood, pellets conforming to standards, as per CAN/CSA-B366.1-M91, size P1, P2, P4.
Untreated wood with limited bark content, compressed by machine and calibrated
Fuel Minimal Diameter Maximal Diameter
P1 - Pellets Small --- ein. (10 mm)
P2 - Pellets Medium ein. (10 mm) cin. (20 mm)
P4 - Briquettes (Pellets Large) cin. (20 mm) 2bin. (60 mm)
CAUTION
Chips have to pass through a 1 in. (25 mm) sieve,
additionally, a fraction of max. 5% of the fuel with a
cross-section of max. cin.² (500 mm²) up to a length
of max. 6ain. (160 mm) can be tolerated.
The Pyrotec is only suitable for burning fuels listed in this
section. A prerequisite for approval is of a fuel by
Viessmann is the approval for the fuel by the responsible
public authorities.
Warranty claims for Viessmann Biomass boilers are
excluded if the following fuel conditions are not met.
- Wood with an increased proportion of bark, tree cuttings from roadside trees (untreated):
Wood remnants from the forestry and sawmill industries or from landscape conservation (likelihood of elevated ash content).
- Remnants from derived timber products:
Usually a mixture of untreated and treated wood in the form of shavings from processing machinery and chips from
choppers.
- Used wood:
This is untreated wood that has been used prior to its energetic utilization (e.g. pallets). It is reduced in size by
shredders for thermal utilization. The metal parts have to be removed by magnetic separators.
General Information
If different fuels are used, Viessmann will not assume any
liability for the functioning or service life of the boiler plant.
Refer to the “Warranty” section in the General Terms and
Conditions of Delivery.
- Burn wood only
- Do not use chemicals or fluids to start fire.
- Do not burn garbage, gasoline, naphtha, engine oil,
or other inappropriate materials.
IMPORTANT
Size of briquettes:
- Fraction of one-offs. max. 5% with cross-section of max. cin.2(500 mm2) up to a length of max. 6ain. (160 mm).
- Frayed surface by chopping tools (shredders) or slow-running choppers.
- Briquettes, diameter max. 2ein. (60 mm).
Consequences of overstepping particle size:
- Increased maintenance because of a substantially higher risk of malfunction
- Shortened service life of the conveyor augers and drives
Size of Wood Chips as per CAN/CSA-B366.1-M91, Grade C7
Total mass 100% G 30 Fine G 50 Medium
Coarse percentage max. 20% Max. cross-section in.2(cm2)b(3) c(5)
Max. length in. (cm) 3g(8.5) 4c(12)
Coarse sieve nominal mesh width in. (mm) f(16) 1a(31.5)
Main percentage 60 to 100% Medium sieve nominal mesh width in. (mm) d(2.8) a(5.6)
Percentage of fines
(incl. ultrafine content) max. 20%
Fine sieve nominal mesh width in. (mm) 1/25 (1) 1/25 (1)

12
5603 882 - 01
Pyrotec Installation & Operating
Wood Fuel Requirements (continued)
General Information
Saw dust
Fuel code Bulk Density kg/m³ [lb/ft³] Water content % Fuel Size Description
aS130 [8.1] W10 to W20 C1 Sawdust, untreated (planing shop)
b1 S200 [12.5] W20 to W35 C1 Sawdust, untreated (sawmill)
c2 S250 [15.6] W35 to W50 C1 Sawdust, untreated (sawmill)
Wood chips
Fuel code Bulk Density kg/m³ [lb/ft³] Water content % Fuel Size Description
b2 S200 [12.5] W20 C7 Forest wood chips, soft, untreated
c1 S250 [15.6] W20 to W35 C7 Forest wood chips, soft, untreated
d1 S300 [18.7] W20 to W35 C7 Forest wood chips, soft/hard, untreated
d2 S300 [18.7] W35 to W50 C7 Forest wood chips, soft, untreated
e1 S350 [21.8] W20 to W35 C7 Forest wood chips, hard, untreated
e2 S350 [21.8] W35 to W50 C7 Forest wood chips, soft/hard, untreated
f1 S400 [24.9] W35 to W50 C7 Forest wood chips, hard, untreated
Shavings and chips
Fuel code Bulk Density kg/m³ [lb/ft³] Water content % Fuel Size Description
gS130 [8.1] Less than W15 C7 Shavings & chips from wood remnants,
dry, mixed
hS200 [12.5] Less than W15 C7 Shavings & chips from wood remnants,
dry, mixed
iS250 [15.6] Less than W15 C7 Shavings & chips from wood remnants,
dry, mixed
Pellets and briquettes
Fuel code Bulk Density kg/m³ [lb/ft³] Water content % Fuel Size Description
jS350 [21.8] Less than W15 P4 Briquettes from wood remnants cin. (20
mm) to max. 2 in. (60 mm)
k1 S650 [40.6] Less than W10 P1 untreated up to ein. (10 mm)
k2 S650 [40.6] Less than W10 P2 untreated ein. to cin. (11 mm to 20 mm)
Maximum water content
The maximum allowable water content of the fuel for Pyrotec systems is limited to 50%.
The water content impacts the maximum boiler output.
Non-wood fuels
Non-wood fuels even if consisting of biomass, such as needles, foliage, grain, straw, fruit pits, etc, are unsuited
as fuel for boiler operation and may not be used.
Limitation super fines and dust [wood particles smaller than 1/32 in. (1.0 mm)]
Max. 10.0% of the total mass; if fuel does not comply with this limit the following process may occur:
- Temperature peaks
- Slag formation
- Even higher temperature
- This process leads to damage by overheating and can affect refractory materials.
Elevated values are especially critical for remnant wood in combination with elevated values of Chlorine and Sulphur.
Suitable fuel types for Pyrotec systems
- Bulk density Sin kg/m³ [lb/ft3], water content (W) in %, size C1, C7, P1, P2, P4 as per CAN/CSA-B366.1-M91.
Note: Fuel for Pyrotec systems allow for a max. of 50% water content (W).
Note: For size of wood chips, see page 11.

13
5603 882 - 01
Pyrotec Installation & Operating
Wood Fuel Requirements (continued)
If fuel does not comply with these limits, there is a risk of corrosion within the heat exchanger and early sintering and
melting of the ash which leads to:
- Shortened life of the heat exchanger
- Increased maintenance costs (firing, combustion chamber door)
The maintenance instructions need to be complied with in order to avoid a process, which will increasingly cause
damage to the boiler.
If maintenance instructions are not complied with the following process may occur:
- Cinders change the airflow
- Temperature peaks
- More slag is produced
- More cinder builds up and changes the airflow more
This process leads to damage by overheating and may affect refractory materials.
Additives in remnant and used wood have to be free of heavy metals and halogen compounds.
Other information
- Ash and cleaning:
Untreated wood without bark produces less than 0.5% ash of the fuel mass supplied. All the specifications
regarding cleaning are based on untreated wood with bark attached with an ash amount of 0.8% of the fuel mass.
If the ash content is higher and/or the ash melting point is lower, increased maintenance and/or cleaning are required.
-Changing fuels:
A substantial change in fuel quality, such as bulk density, water content, dust proportion or ash content might require
a manual correction of the firing parameters (see Operating section).
Content limits for non-combustible substances
- No wood fuels may contain any foreign bodies, such as pieces of metal, stones, masonry remnants or plastics.
The following limits (per lb/kg of dry fuel) of contained non-combustible substances apply [ash analyzed at a
temperature of 1500° F (815° C)]:
Substance Limit Comparative value untreated forest wood
Chlorine (Cl) max. 300 ppm (300 mg/kg) 10 ppm (10 mg/kg)
Sulphur (S) max. 1000 ppm (1000 mg/kg) 120 ppm (120 mg/kg)
Total Cl, S max. 1000 ppm (1000 mg/kg) 130 ppm (130 mg/kg)
Ash content, total max. 0.25 oz/lb (15.0 g/kg) 0.08 oz/lb (5.0 g/kg)
Alkali oxides in the ash (K2O and Na2O) max. 0.016 oz/lb (1.0 g/kg) 0.006 oz/lb (0.35 g/kg)
Sintering point of the ash min. 1800° F (1000° C) approx. 2200° F (1200° C)
General Information

14
5603 882 - 01
Pyrotec Installation & Operating
Safety
Carbon Monoxide
CAUTION
Do not use this boiler if any part has been under water.
Immediately call a qualified heating contractor to inspect
the boiler and to replace any part of the control system
which has been under water.
The U.S. Consumer Product Safety Commission strongly
recommends the installation of carbon monoxide detectors
in buildings in which wood-burning equipment is installed.
Carbon monoxide (CO) is a colorless, odorless gas, which
may be produced during incomplete combustion of fuel
and/or when the flame does not receive an adequate
supply of combustion air. Carbon monoxide can cause
severe personal injury or loss of life.
Therefore, carbon monoxide detectors that are in
compliance with a nationally recognized standard
(e.g. ANSI/UL 2034-2002, CSA 6.19-01) should be
installed and maintained in buildings that contain wood-
burning equipment.
Note: Viessmann does not test any detectors and makes
no representation regarding any brand or type of
detector.
For safe operation
We recommend that you frequently:
- Check for debris which could obstruct the flow of
flue gases. The vent or chimney must not be blocked.
A blocked or partially blocked vent or chimney can
cause flue gases to leak into the structure. Flue gases
leaking into the house can cause injury or death.
Blocked or partially blocked chimneys must have the
blockage removed by a qualified heating contractor.
- Check the pressure gauge for correct system (water)
pressure. Check for water on the floor from the
discharge pipe of the pressure relief valve or any
other pipe, pipe joint, valve or air vent.
- Check for moisture, water, or appearance of rust
on the flue gas pipes, their joints as well as vent
dampers, or side wall vent terminals (if so equipped).
- Ensure that nothing is obstructing the flow of
combustion and ventilation air and no chemicals,
garbage, gasoline, combustible materials, flammable
vapors and liquids are stored (not even temporarily)
in the vicinity of the boiler.
- DO NOT allow unsupervised children near the boiler.
Service/inspection of the boiler and the system must be
performed on a regular basis. Maintenance, service and
cleaning are specified in the “Service and Maintenance
Instructions”.
Before the heating season begins, it is recommended that
the boiler be serviced by a qualified heating contractor.
WARNING
As there are no user-serviceable parts on the boiler,
or control, the end-user must not perform service
activities of any kind on system components. Failure
to heed this warning can cause property damage,
severe personal injury, or loss of life.
WARNING
Improper installation, adjustment, service, or maintenance
can cause flue products to flow into living space. Flue
products contain poisonous carbon monoxide gas, which
can cause nausea or asphyxiation resulting in severe
personal injury or loss of life.
WARNING
The operator/ultimate owner is required to have the
heating boiler and controls checked, as a minimum
once per year, by the original installer or by a competent
heating contractor familiar with the equipment. Defects
must be corrected immediately.

15
5603 882 - 01
Pyrotec Installation & Operating
WARNING
Inhaling of fiberglass wool and/or ceramic fiber
materials is a possible cancer hazard. These materials
can also cause respiratory, skin and eye irritation.
Hazardous Materials
Fiberglass wool and ceramic fiber materials
WARNING
Appliance materials of construction, products of
combustion and the fuel contain alumina, silica, heavy
metals, carbon monoxide, nitrogen oxides, aldehydes
and/or other toxic or harmful substances which can
cause serious injury or loss of life and which are known
to the State of California to cause cancer, birth defects
and other reproductive harm. Always use proper safety
clothing, respirators and equipment when servicing or
working nearby the appliance.
The state of California has listed the airborne fibers of
these materials as a possible cancer hazard through
inhalation. When handling these materials, special care
must be applied.
First aid measures
- If eye contact occurs, flush eyes with water to
remove dust. If symptoms persist, seek medical
attention.
- If skin contact occurs, wash affected areas gently
with soap and warm water after handling.
Suppliers of ceramic fiber products recommend the
following first aid measures
- Respiratory tract (nose and throat) irritation:
If respiratory tract irritation develops, move the
person to a dust free location.
-Eye irritation:
If eyes become irritated, flush immediately with
large amounts of lukewarm water for at least 15
minutes. Eyelids should be held away from the
eyeball to ensure thorough rinsing. Do not rub eyes.
- Skin irritation:
If skin becomes irritated, remove soiled clothing.
Do not rub or scratch exposed skin. Wash area of
contact thoroughly with soap and water. Using a
skin cream or lotion after washing may be helpful.
- Gastrointestinal irritation:
If gastrointestinal tract irritation develops, move
the person to a dust free environment.
Suppliers of fiberglass wool products recommend the
following precautions be taken when handling these
materials
- Avoid breathing fiberglass dust and contact with
skin and eyes.
- Use NIOSH approved dust/mist respirator.
- Wear long-sleeved, loose fitting clothing, gloves
and eye protection.
- Wash work clothes separately from other clothing.
Rinse washer thoroughly.
- Operations such as sawing, blowing, tear-out and
spraying may generate airborne fiber concentration
requiring additional protection.
Safety

16
5603 882 - 01
Pyrotec Installation & Operating
Safety
Power Failure Provision
The PYROTEC Grate Firing System is equipped with
a flue gas exhaust blower.
This boiler must be properly vented. Use a vent material
certified for use with solid-fuel fired equipment.
This boiler shall be connected to:
a) a masonry chimney conforming to local regulations
or, in the absence of such regulations, to the
requirements of the National Building Code
b) a certified factory-built chimney (refer to the NFPA
211 standard).
A flue pipe serving this boiler shall be constructed of
steel or other suitable material with a melting point of
not less than 2000° F (1100° C).
Do not use galvanized steel
IMPORTANT
Customers must ensure that there is a supply of water
independent of the electrical supply. This design ensures
that in case of a power failure, the boiler will be reliably
cooled by the thermal safety flush valve.
Power Failure Provision
For installations in Canada:
The boiler venting system must be tested and listed by
a Nationally Recognized Testing Lab such as ULC/CSA
for solid fuel burning appliances.
The PYROTEC Grate Firing System is output-controlled
within a range from 30%-100% of the rated boiler output.
This produces flue gas temperatures from min. 212° F
(100° C) to max. 482° F (250° C).
An insulated chimney should be provided to prevent sooting.
The distance from the flue gas exhaust blower to the
chimney should be as short as possible. 90° elbows
should be avoided if possible. Flue gas pipes of more than
3 ft. (1 m) in length must be insulated.
The connection to the chimney should be made such that
it rises at an angle of 30°- 45° (to prevent excess ash
accumulating in the lateral section of the vent pipe).
The flue gas line, including the lead-in into the chimney,
must be gas-tight.
Venting Requirements

17
5603 882 - 01
Pyrotec Installation & Operating Safety
Mechanical Room
No temperature-sensitive pipes or lines may be installed
in the floor beneath the heating boiler.
The temperature in the heating room must not exceed
104° F (40° C) while the system is in operation
(in the area approx. 3 ft. (1 m) away from the boiler).
The temperature in the heating room must not fall below
50° F (10° C) while the system is in operation (measured
at the inner side of exterior walls).
Dimensions shown in. (mm)
Hatched surface Heat-resistant floor
Medium grey surface Boiler supporting surface
Ensure the mechanical room complies with the requirements
in these instructions and local codes.
Viessmann recommends the installation of an additional
electrical disconnect switch and a fuel shut-off valve (if
possible) outside the mechanical room or enclosed area
of installation.
A separate, dry heating room must always be provided
for the PYROTEC Grate Firing System. No combustible
materials may be stored in the heating room. The heating
boiler may only be set up on a fire and temperature-
resistant floor.
The load-bearing capacity of the heating room floor must
be designed for the weight of the system plus filling with
water and fuel. The load-bearing capacity of the floor in
the area of the boiler bearing surface must be 512 lb/ft²
(2500 kg/m²).
IMPORTANT
Always follow the most up-to-date local, municipal and
building regulations and codes.
The minimum distance to the walls and ceiling required
according to the table of dimensions for proper cleaning
and maintenance of the boiler must be complied with.
A sufficient supply of fresh air must be provided directly
from outdoors into the heating room. Induced ventilation is
necessary for heating rooms that are confined or enclosed.
Foundation dimensions
Boiler Model KPT- 390 530 720 950 1250
a in. (mm) 40e(1026) 40e(1026) 43c(1112) 53b(1360) 53b(1360)
b in. (mm) 717
/8(1826) 717
/8(1826) 75a(1912) 85 (2160) 85 (2160)
c in. (mm) 166d(4221) 166d(4721) 193e(4912) 200f(5096) 2221
/8(5641)
d in. (mm) 49f(1260) 49f(1260) 551
/8(1400) 641 /8(6030) 64d(1630)
e in. (mm) 1007
/8(2561) 120b(3061) 122b(3112) 120c(3066) 142d(3611)

18
5603 882 - 01
Pyrotec Installation & Operating
WARNING
Incorrect ambient conditions can lead to damage to
the heating system and put safe operation at risk.
Mechanical room conditions
Prevent the air from becoming contaminated by homogenate
hydrocarbons (e.g. as contained in paints solvents or
cleaning fluids) and excessive dust (e.g. through grinding
or polishing work). Combustion air for the heating
process, and ventilation of the boiler room must be free of
corrosive contaminants. To that end, any boiler must be
installed in an area that has no chemical exposure.
For the main, currently known sources refer to “Sources
of combustion and ventilation air contaminants”.
Avoid continuously high levels of humidity (e.g. through
frequent drying of laundry).
Never close existing ventilation openings.
Sources of combustion and ventilation air contaminants
Areas likely to contain contaminants:
- New building construction
- Swimming pools
- Remodeling areas, hobby rooms
- Garages with workshops
- Furniture refinishing areas
- Dry cleaning/laundry areas and establishments
- Auto body shops
- Refrigeration repair shops
- Metal fabrication plants
- Plastic manufacturing plants
- Photo processing plants
- Beauty salons
Products containing contaminants:
- Chlorine-type bleaches, detergents and cleaning
solvents found in household laundry rooms
- Paint and varnish removers
- Hydrochloric acid, muriatic acid
- Chlorine-based swimming pool chemicals
- Spray cans containing chlorofluorocarbons
- Chlorinated waxes and cleaners
- Cements and glues
- Refrigerant leaks
- Calcium chloride used for thawing
- Sodium chloride used for water softening salt
- Permanent wave solutions
- Adhesives used to fasten building products and other
similar items
- Antistatic fabric softeners used in clothes dryers
Components which are not tested with the heating
system may damage the heating system or affect its
functions. Installation or replacement may only be carried
out be a qualified heating contractor.
IMPORTANT
WARNING
The boiler must not be located in areas or rooms where
chemicals are stored, or aggressive vapors (i.e. bleach,
hair spray, methyl chloride, carbon tetrachloride or
perchloroethylene) or high dust levels or humidity levels
are present. Heat exchanger corrosion might occur and
reduce the lifetime of the boiler significantly. If above
criteria are not properly observed and boiler damage
results, any warranty on the complete boiler and related
components will be null and void.
Mechanical Room (continued)
Safety

19
5603 882 - 01
Pyrotec Installation & Operating
Codes
Provision for combustion and ventilation air must be made
in accordance with applicable local codes.
In the absence of local codes, use:
CSA B365-10, Installation Code for Solid Fuel Burning
Appliances and Equipment.
Always use latest edition codes.
General
This equipment requires fresh air for safe operation
and must be installed ensuring provisions for adequate
combustion and ventilation air exist.
Whenever possible, install boiler near an outside wall so
that it is easy to duct fresh air directly to the boiler area.
The boiler location must never be under negative pressure.
Flue gas exhaust blowers, attic blowers, or dryer blowers
may cause air to be exhausted at a rate higher than air
can enter the structure for safe combustion.
The heating contractor shall ensure all of the following
requirements are met:
- An adequate supply of combustion air must be
available to ensure proper combustion.
- Ambient air temperatures must be maintained within
safe operating limits.
- When a damper is provided in any opening intended
to admit combustion air into the room within which
the appliance is installed, the damper shall be
interlocked to prevent any burner from starting
before the damper is fully open.
- Each duct used to convey air from the outdoors shall
have:
1. a cross-sectional area throughout its length at
least equal to the free area of the inlet and outlet
openings which it connects,
2. making a provision for outside combustion air,
the intake shall not be less than 1 ft. (0.3 m)
above the anticipated snow level for the location.
- The heating contractor must check with local
authorities (municipal building department) for
combustion air requirements particular to the area.
WARNING
Failure to provide an adequate supply of fresh combustion
air can cause poisonous flue gases to enter living space.
Flue gases entering living space can cause carbon
monoxide poisoning which can result in severe personal
injury or loss of life.
WARNING
Never cover the boiler or store debris or other materials
near the boiler, or in any way block the flow of adequate
fresh air to the boiler. Never cover the combustion air
opening. Advise system operator / ultimate owner
accordingly.
Confined spaces
When a furnace or boiler is enclosed in a space that has
a volume less than 20% of that to be heated by the
appliance, the space shall:
a. have a permanent opening or openings for natural air
circulation with a minimum net free area of 1.5 in² /
1000 Btu/h (3300 mm² / kW) input, and
b. connect to another space or spaces such that the total
volume of air available for natural air circulation is
at least 30% of the total volume to be heated by the
appliance.
The minimum dimension of any opening specified in item
(a) shall be no less than 1 in. (25 mm) The lower edge of
at least one opening shall be located within 1.5 ft. (0.5 m)
of the floor of the enclosed space, and the upper edge of
at least one opening shall be located within 1.5 ft. (0.5 m)
of the ceiling of the enclosed space.
Note: The intent of this Clause is to allow either one
long vertical opening or two shorter horizontal
openings, one high and the other low, to allow
for air circulation to prevent overheating of the
appliance.
Unconfined spaces
Where the boiler is located in an unconfined space in
a building having insufficient infiltration, additional air
for combustion and ventilation shall be obtained from
outdoors or from spaces freely communicating with the
outdoors. Under these conditions, permanent opening(s)
shall be provided so that the total air received through
these openings will be at least as much as would be
admitted by openings having a total free area of 1 in² /
5,000 Btu/h or (450 mm² / kWh) of the total input rating
of all wood-fired appliances.
Louvers and grilles
In calculating free area as specified, consideration shall
be given to the blocking effect of louvers, grilles, or
screens that protect openings. Screens shall be no
smaller than ¼ in. (6 mm) mesh and shall be readily
accessible for cleaning. If the free area through a design
of louver or grilles is known, it shall be used in calculating
the size of opening required to provide the free area
specified. If the design and free area are not known, it
shall be assumed that wood louvers have 20 - 25% free
area and metal louvers and grilles have 60 - 75% free
area.
Combustion Air Supply
Safety

20
5603 882 - 01
Pyrotec Installation & Operating
Technical Data
Boiler model KPT- 390 530 720 950 1250
Maximum output MBH (kW) 1331 (390) 1808 (530) 2457 (720) 3242 (950) 4265 (1250)
Minimum output1MBH (kW) 334 (98) 450 (132) 614 (180) 812 (238) 1065 (312)
Efficiency285%
Fuel Moisture content3% W 50
Size of wood chips4G 30 / G 50 as per CAN/CSA-B366. 1-M91
Flue gas figures
Connection flue gas pipe 7A
Mass flow rate; W5; O26%
Volume flow; W5; O26%; 302°F (150ºC)
Mass flow rate; W35; O28%;
Volume flow;W35; O28%; 302°F (150ºC)
Average flue gas temperature at full load5
Average flue gas temperature at partial load5
Chimney draft required
in. mm
lb/s (g/s)
ft³/s (m³/s)
lb/s (g/s)
ft³/s (m³/s)
°F (°C)
°F (°C)
Pa
13b(350)
0.48 (219)
9.18 (0.26)
0.67 (303)
13 (0.37)
13c(350)
0.65 (297)
12.71 (0.36)
0.91 (412)
17.5 (0.50)
13c(350)
0.89 (404)
17 (0.48)
1.23 (560)
23.6 (0.67)
15c(400)
1.17 (532)
22 (0.63)
1.62 (736)
31 (0.88)
17c(450)
1.54 (700)
29 (0.83)
2.13 (968)
40.6 (1.15)
320 (160)
248 (120)
±0
Electrical connections
Electrical connections, total
Ignition device
Flue gas exhaust blower
In-feed auger
Primary air blower 1
Primary air blower 2
Secondary air blower
Grate drive unit
Electric power consumption at full load
Electric power consumption at partial load
kW
kW
kW
kW
kW
kW
kW
kW
kW
kW
6.42
1.6
1.5
1.1
0.14
1.0
.9
0.12
3.36
2.75
8.28
1.6
2.2
1.5
0.3
1.0
1.5
0.12
4.68
3.83
8.28
1.6
2.2
1.5
0.3
1.0
1.5
0.12
4.68
3.83
9.51
1.6
2.2
2.2
0.48
1.0
1.85
0.12
5.29
4.28
11.31
1.6
4.0
2.2
0.48
1.0
1.85
0.12
6.91
5.6
Heating
Water side resistance (diff. 27° F / 15 K)
Boiler water volume
Heating surface
Volume on heating gas side
Volume of ash container for grate ash
Volume of ash container for flue gas cyclone
Test pressure6
Maximum allowable working pressure (water)
6
Maximum water temperature
Minimum return temperature
“wc (mbar)
USG (L)
ft² (m²)
USG (L)
USG (L)
USG (L)
psi (bar)
psi (bar)
°F (°C)
°F (°C)
5.12 (13)
303 (1150)
291.8 (27.1)
407 (1540)
9.23 (23)
383 (1450)
457.5 (42.5)
602 (2280)
17.26 (43)
488 (1850)
597.4 (55.5)
774 (2830)
10.5 (26)
515 (1950)
805.2 (74.8)
1070 (4050)
18 (45)
660 (2500)
979.6 (91.0)
1367 (5210)
63 (221) - 240 (800)
63 (221) - 240 (800)
113 (7.8)
30 or 60 (2 or 4)
250 (120)
149 (65)
Weight
Weight of combustion chamber
Weight of pressure vessel (30 psi)
Weight of pressure vessel (60 psi)
Weight of displacement rods
Weight of flue gas exhaust blower
Weight of in-feed auger
Total weight without water (30psi) 7
Total weight without water (60psi) 7
Total weight with water (30psi) 7
Total weight with water (60psi) 7
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
6570 (2970)
4993 (2265)
4993 (2265)
644 (292)
132 (60)
337 (153)
12820(5815)
12820(5815)
15355(6965)
15355(6965)
9343 (4238)
7094 (3218)
7094 (3218)
721 (327)
172 (78)
337 (153)
17780(8065)
17780(8065)
20964(9509)
20964(9509)
10919 (4953)
9275 (4207)
9936 (4507)
869 (394)
178 (78)
3.37 (153)
21572(9785)
22234(10085)
25675(11646)
26336(11946)
12740(5779)
12965 (5881)
13627 (6181)
1186 (538)
181 (82)
419 (190)
27492(12470)
28153(12770)
31775(14413)
32437(14713)
14374(6520)
14643 (6642)
15525 (7042)
1186 (538)
236 (107)
419 (190)
30858(13997)
31740(14397)
36330(16479)
37212(16879)
1Minimum load: Operation with modulated control (Infinitely variable power control)
Low load with ON Qmin / OFF (Stop-and-go mode)
2Moist fuels: Efficiency: Specification with displacement rods and flue gas recirculation system
or dry fuels (W5 to W20) without flue gas recirculation system-reduced values
3Wet fuels: >W35 further limitations regarding output, degree of efficiency and control behavior
4Specification: See Section Wood Fuel Requirements
5Flue gas temperature: An increase is possible by removing the displacement rods [Full load 86° F (30° C);
Partial load 50° F (10° C)]
6Pressure: Per ASME Sec. IV
7Overall weight: Includes displacement rods
Other influences: Fuel, water content, ash content, pneumatic cleaning system yes/no; track time (number of
operating hours without cleaning). Specifications for the start of the track time [toward the end
of the track time there is an increase in the flue gas temperature by approx. 59° F (15° C)
Mechanical