Viessmann KOB Pyrotec KPT Series, KOB Pyrotec KPT390, KOB Pyrotec KPT530, KOB Pyrotec KPT720, KOB Pyrotec KPT950 Technical Data Manual

Technical Data Manual

for use by engineers and heating contractors

Pyrotec

Wood-fired Boiler
KPT 390 to KPT 1250 Series

r

Product may not be exactly as shown

Pyrotec with an attached external grate and a moving
annealing grate to achieve optimal combustion results.
A feed auger continuously moves the wood fuel onto
the burner trough where gasification takes place.
The combustible gases blend with precisely controlled
secondary air, resulting in a complete combustion and
the thermal energy is released into the boiler’s triple-pass
heat exchanger.
Max. output: 390 to 1250 kW (1331 to 4266 MBH)
Min. output: 98 to 370 kW (334 to 1263 MBH)

5443 113 v1.9 05/2013

Product Information

Pyrotec

Pyrotec Technical Data

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.

Specifications

Fully-automatic underfeed combustion wood-fired

boiler

5 models from 1330 to 4268 MBH

For wood fuels with max. water content of 50%

Efficiency: 85%

Available for 30 or 60 psi max. operating pressure

Benefits at a glance

High efficiency with advanced combustion technology,
triple-pass heat exchanger and modulating output
control (turndown ratio 4:1)

Maximum heat transfer with triple-pass heat
exchanger design.

High efficiency and ultra-low emissions with precisely
controlled primary and secondary air.

Low maintenance with fully-automatic de-ashing,
optional pneumatic cleaning system and flue gas
de-duster.

Advanced safety equipment ensures safe and reliable
operation.

Maximum system performance with heavy-duty
construction and all system components from one
source.

Automatic ignition device limits idling and saves fuel.

Custom design of your system by our team of experts.

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 B365-01
Installation Code for Solid Fuel Burning Appliances
and Equipment

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.

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.

Note: “Pyrotec” is an alternate/interchangeable trade

name with “Pyrtec”.

2

5443 113 v1.9

Pyrotec Technical Data

Boiler Description

General Information

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 ignition blower (optional). The boiler
features a reliable burner trough, a descending grate and
a moving burn-out grate made from highly-refractory
cast steel [approx. b in. (12 mm)]. These items allow
to achieve excellent performance control and highest
safety against back-burn in conjunction with an automatic
de-ashing system (optional) for the combustion chamber.
The solid, horizontally positioned and large-volume
fire box 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 fire box.

- In the upper part of the fire box, 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 fire box door is solidly constructed, air-cooled and
very well insulated. The fire box door is equipped with
solid double-jointed hinges for easy maintenance.
The heat is transferred to the water in the horizontal
tube heat exchanger. The boiler is well insulated and
highly accessible through the boiler door on the front.
A pneumatic cleaning system (optional) can be installed
at the insulated boiler door.

- The flue gas 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
de-duster (optional).

5443 113 v1.9

Supplied with:

- Boiler with fire box and pressure vessel / tube heat
exchanger including supply and return temperature
sensors and over pressure monitor

- Fire box 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, extinguisher valve with strainer, extinguisher
water container with mounting bracket

- Flue gas blower including flue gas temperature sensor
and oxygen sensor

- Boiler cleaning tools for the fire box, combustion
chamber and tube 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 mixing valve, boiler pump and hot water
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 de-duster 63 USG (240 L)

- Flue gas de-duster 211 USG (800 L)

- Automatic de-ashing system in bin, 63 USG (240 L)

- Automatic de-ashing system in bin, 211 USG (800 L)

- Pneumatic cleaning system

- Automatic ignition blower

- 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 hot water storage tank management system

- External control module for field supplied extraction
system

- Output module / Input module

- Input module 0-10V

- ModBus

- BacNet gateway

- Visualization

3

General Information

Transport and Installation

IMPORTANT

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 fire box 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 fire box 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.

WARNING

Pyrotec Technical Data

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 B 365-01,
Installation Code for Solid-Fuel Burning Appliances
and Equipment.

A Lifting lugs (screw in before lifting)
B Lifting lugs (pressure vessel)

4

5443 113 v1.9

Pyrotec Technical Data

Delivery Condition

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:

- Tube heat exchanger door is mounted to the tube heat
exchanger

- Fire box door is mounted to the fire box

- Flue gas collector is attached to the tube heat exchanger

- Pneumatic cleaning system (optional) is attached to the
tube heat exchanger door

General Information

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 fire box

- Brickwork to connect the fire box and the combustion
chamber, bricks and mortar are included

- Electrical components which include temperature
sensors, oxygen sensor, light barriers for the fire box,
ignition
blower, low water cut off, safety temperature limiter,
overpressure monitor 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 fire box grate is detached

- De-ashing system (optional) and drive for the
de-ashing system

- Air compressor (optional) and connection to the
pneumatic cleaning system (optional)

- The flue gas blower is not attached to the flue gas
collector

- Primary air blowers are not attached to the fire box

- Secondary air blowers are not attached to the fire box

- Re-circulation system (optional)

- Flue gas de-duster (optional) comes in two pieces

- The in-feed auger is detached from the fire box

- 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

Measurements for the fire box as standard delivery condition

Boiler model KPT390 KPT530 KPT720 KPT950 KPT1250

Minimum size
door (W x H)

Minimum ceiling
opening (W x H)

Measurements for the pressure vessel as standard delivery condition

Boiler model KPT390 KPT530 KPT720 KPT950 KPT1250

Minimum size
door (W x H)

Minimum ceiling
opening (W x H)

59 in. x 59 in.
(1500 mm x
1500 mm)

59 in. x 149 in.
(1500 mm x
3800 mm)

59 in. x 59 in.
(1500 mm x
1500 mm)

59 in. x 112a in.
(1500 mm x
2850 mm)

63 in. x 69 in.
(1600 mm x
1750 mm)

63 in. x 157b in.
(1600 mm x
4000 mm)

63 in. x 69 in.
(1600 mm x 1750
mm)

63 in. x 112a in.
(1600 mm x
2850 mm)

63 in. x 69 in.
(1600 mm x
1750 mm)

63 in. x 196c in.
(1600 mm x
5000 mm)

63 in. x 69 in.
(1600 mm x
1750 mm)

63 in. x 126 in.
(1600 mm x
3200 mm)

74c in. x 73c in.
(1900 mm x
1850 mm)

74c in. x 196c in.
(1900 mm x
5000 mm)

74c in. x 73c in.
(1900 mm x
1850 mm)

74c in. x 130 in.
(1900 mm x
3300 mm)

74c in. x 78c in.
(1900 mm x
2000 mm)

74c in. x 216b in.
(1900 mm x
5500 mm)

74c in. x 78c in.
(1900 mm x
2000 mm)

74c in. x 137c in.
(1900 mm x
3500 mm)

5443 113 v1.9

5

General Information

Wood Fuel Requirements

Pyrotec Technical Data

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.

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 ---

P2 - Pellets Medium

P4 - Briquettes (Pellets Large)

- 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.

e in. (10 mm) c in. (20 mm)

c in. (20 mm) 2b in. (60 mm)

IMPORTANT

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.

e in. (10 mm)

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)

Main percentage 60 to 100% Medium sieve nominal mesh width in. (mm)
Percentage of fines

(incl. ultrafine content) max. 20%

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. c in.² (500 mm²) up to a length
of max. 6a in. (160 mm) can be tolerated.

6

Max. length in. (cm)
Coarse sieve nominal mesh width in. (mm)

Fine sieve nominal mesh width in. (mm)

Size of briquettes:

- Fraction of one-offs. max. 5% with cross-section of
max. c in.2 (500 mm2) up to a length of max. 6a in.
(160 mm).

- Frayed surface by chopping tools (shredders) or slow­ running choppers.

- Briquettes, diameter max. 2e in. (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

b (3) c (5)

3g (8.5) 4c (12)

f (16) 1a (31.5)

d (2.8) a (5.6)

1

/

(1)

25

1

/

(1)

25

5443 113 v1.9

Pyrotec Technical Data

Wood Fuel Requirements (continued)

General Information

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.

Suitable fuel types for Pyrotec systems

- Bulk density S in 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).

Saw dust
Fuel code Bulk Density kg/m³ [lb/ft³] Water content % Fuel Size Description

a S130 [8.1]
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]
c1 S250 [15.6]
d1 S300 [18.7]

d2 S300 [18.7]

e1 S350 [21.8]
e2 S350 [21.8]

f1 S400 [24.9]

W10 to W20 C1 Sawdust, untreated (planing shop)

W20 C7 Forest wood chips, soft, untreated
W20 to W35 C7 Forest wood chips, soft, untreated
W20 to W35 C7 Forest wood chips, soft/hard, untreated

W35 to W50 C7 Forest wood chips, soft, untreated

W20 to W35 C7 Forest wood chips, hard, untreated
W35 to W50 C7 Forest wood chips, soft/hard, untreated
W35 to W50 C7 Forest wood chips, hard, untreated

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.

Shavings and chips

Fuel code Bulk Density kg/m³ [lb/ft³] Water content % Fuel Size Description

g S130 [8.1] Less than W15 C7

h S200 [12.5] Less than W15 C7

i S250 [15.6] Less than W15 C7

Pellets and briquettes

Fuel code Bulk Density kg/m³ [lb/ft³] Water content % Fuel Size Description

j S350 [21.8] Less than W15 P4

k1 S650 [40.6] Less than W10 P1
k2 S650 [40.6] Less than W10 P2

Note: For size of wood chips, see page 6.

5443 113 v1.9

Shavings & chips from wood remnants,
dry, mixed

Shavings & chips from wood remnants,
dry, mixed

Shavings & chips from wood remnants,
dry, mixed

Briquettes from wood remnants c in. (20
mm) to max. 2 in. (60 mm)

untreated up to e in. (10 mm)
untreated e in. to c in. (11 mm to 20 mm)

7

General Information

Pyrotec Technical Data

Wood Fuel Requirements (continued)

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)

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 tube heat exchanger

- Increased maintenance costs (firing, boiler 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).

8

5443 113 v1.9

Pyrotec Technical Data

Power Failure Provision

Power Failure Provision

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 run-off safety valve.

Venting Requirements

Safety

The PYROTEC Grate Firing System is equipped with
a flue gas 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).

IMPORTANT

Do not use galvanized steel

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 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.

5443 113 v1.9

9

Safety

Mechanical Room

Pyrotec Technical Data

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 temperature­resistant floor.

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).

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.

Dimensions shown in. (mm)

Hatched surface Heat-resistant floor
Medium grey surface Boiler supporting surface

Foundation dimensions

Boiler Model KPT- 390 530 720 950 1250

a in. (mm)

b in. (mm) 717/8 (1826)

c in. (mm)

d in. (mm)

e in. (mm) 1007/8 (2561)

40e (1026) 40e (1026) 43c (1112) 53b (1360) 53b (1360)

717/8 (1826) 75a (1912)

166d (4221) 166d (4721) 193e (4912) 200f (5096)

49f (1260) 49f (1260)

120b (3061) 122b (3112) 120c (3066) 142d (3611)

551/8 (1400) 641/8 (6030)

85 (2160) 85 (2160)

2221/8 (5641)

64d (1630)

10

5443 113 v1.9

Pyrotec Technical Data

Combustion Air Supply

Safety

Codes

Provision for combustion and ventilation air must be made
in accordance with applicable local codes.
In the absence of local codes, use:
CSA B365-01, Installation Code for Solid Fuel Burning
Appliances and Equipment.
Always use latest edition codes.

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.

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.
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.

5443 113 v1.9

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 Spacess

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.

11

Mechanical

Pyrotec Technical Data

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 output

Efficiency

Fuel Moisture content

Size of wood chips

Flue gas figures

Connection flue gas pipe 7 A
Mass flow rate; W5; O2 6%
Volume flow; W5; O2 6%; 302°F (150ºC)
Mass flow rate; W35; O2 8%;
Volume flow;W35; O2 8%; 302°F (150ºC)

Average flue gas temperature at full load
Average flue gas temperature at partial load

Chimney draft required

Electrical connections

Electrical connections, total
Ignition device
Flue gas blower
In-feed auger
Primary air flow blower
Primary air flow blower
Secondary air flow blower
Grate drive unit
Electric power consumption at full load
Electric power consumption at partial load

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 de-duster
Test pressure
Maximum allowable working pressure (water)
Maximum water temperature
Minimum return temperature

Weight

Weight of fire box
Weight of pressure vessel (30 psi)
Weight of pressure vessel (60 psi)
Weight of displacement rods
Weight of flue gas blower
Weight of in-feed auger
Total weight without water (30psi)
Total weight without water (60psi)
Total weight with water (30psi) 7
Total weight with water (60psi)

1

Minimum load: Operation with modulated control (Infinitely variable power control)

Low load with ON Qmin / OFF (Stop-and-go mode)

2

Moist fuels: Efficiency: Specification with displacement rods and flue gas recirculation system

or dry fuels (W5 to W20) without flue gas recirculation system-reduced values

3

Wet fuels: >W35 further limitations regarding output, degree of efficiency and control behavior

4

Specification: See Section Wood Fuel Requirements

5

Flue gas temperature: An increase is possible by removing the displacement rods [Full load 86° F (30° C);

Partial load 50° F (10° C)]

6

Pressure: Per ASME Sec. IV

7

Overall 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).

12

1

2

3

4

5
5

1
2

6

7
7

7

MBH (kW) 334 (98) 450 (132) 614 (180) 812 (238) 1065 (312)

85%

% W 50

G 30 / G 50 as per CAN/CSA-B366. 1-M91

ft³/s (m³/s)

ft³/s (m³/s)

“wc (mbar)

6

in. mm

lb/s (g/s)

lb/s (g/s)

°F (°C)
°F (°C)

Pa

kW
kW
kW
kW
kW
kW
kW
kW
kW
kW

USG (L)

ft² (m²)

USG (L)

USG (L)

USG (L)
psi (bar)
psi (bar)

°F (°C)
°F (°C)

lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)
lb (kg)

13b (350)

0.48 (219)

9.18 (0.26)

0.67 (303)
13 (0.37)

6.42

1.6

1.5

1.1

0.14

1.0
.9

0.12

3.36

2.75

5.12 (13)

303 (1150)

291.8 (27.1)
407 (1540)

6570 (2970)
4993 (2265)
4993 (2265)

644 (292)

132 (60)

337 (153)
12820(5815)
12820(5815)
15355(6965)
15355(6965)

13c (350)

0.65 (297)

12.71 (0.36)

0.91 (412)

17.5 (0.50)

8.28

1.6

2.2

1.5

0.3

1.0

1.5

0.12

4.68

3.83

9.23 (23)

383 (1450)

457.5 (42.5)
602 (2280)

9343 (4238)
7094 (3218)
7094 (3218)

721 (327)

172 (78)

337 (153)
17780(8065)
17780(8065)
20964(9509)
20964(9509)

13c (350)

0.89 (404)
17 (0.48)

1.23 (560)

23.6 (0.67)

320 (160)
248 (120)

±0

8.28

1.6

2.2

1.5

0.3

1.0

1.5

0.12

4.68

3.83

17.26 (43)

488 (1850)

597.4 (55.5)
774 (2830)

63 (221) - 240 (800)
63 (221) - 240 (800)

113 (7.8)

30 or 60 (2 or 4)

250 (120)

149 (65)

10919 (4953)
9275 (4207)
9936 (4507)

869 (394)

178 (78)

3.37 (153)
21572(9785)
22234(10085)
25675(11646)
26336(11946)

805.2 (74.8)
1070 (4050)

12740(5779)
12965 (5881)
13627 (6181)

27492(12470)
28153(12770)
31775(14413)
32437(14713)

15c (400)

1.17 (532)
22 (0.63)

1.62 (736)
31 (0.88)

9.51

1.6

2.2

2.2

0.48

1.0

1.85

0.12

5.29

4.28

10.5 (26)

515 (1950)

1186 (538)

181 (82)

419 (190)

17c (450)

1.54 (700)
29 (0.83)

2.13 (968)

40.6 (1.15)

11.31

1.6

4.0

2.2

0.48

1.0

1.85

0.12

6.91

5.6

18 (45)

660 (2500)

979.6 (91.0)
1367 (5210)

14374(6520)
14643 (6642)
15525 (7042)

1186 (538)

236 (107)

419 (190)
30858(13997)
31740(14397)
36330(16479)
37212(16879)

5443 113 v1.9

Pyrotec Technical Data

Specifications

Boiler Dimensions

Mechanical

BR

BS

BR Boiler Return
BS Boiler Supply

Dimensions

Boiler Model KPT- 390 530 720 950 1250

a in. (mm)

b in. (mm)

c in. (mm)

d in. (mm)

e in. (mm)

f in. (mm)

g in. (mm)

h in. (mm)

k in. (mm)

l in. (mm)

m in. (mm)

n in. (mm)

o in. (mm)

p in. (mm)

5443 113 v1.9

5

/

93

8 (2378) 99

5

/

91

8 (2328) 97

172 (4370) 191¾ (4870) 207 (5257) 214½ (5447) 235

1

/

87

8 (2060) 100¾ (2560) 100

22¾ (577) 22¾ (577) 22¾ (577) 25

47¼ (1200) 47¼ (1200) 47¼ (1200) 50¼ (1275) 50¼ (1275)

94¾ (2405) 114

42¾ (1086) 42¾ (1086) 54

5

/

31

8 (803) 31

7

/

17

8 (453) 17

81¾ (2077) 91¾ (2331) 98

1

/

12

8 (308) 12

1

/

50

8 (1274) 50

49¾ (1263) 55¾ (1417) 55

7

/

8 (2536) 111

7

/

8 (2486) 109

3

/

8 (2905) 117

5

/

8 (803) 31

7

/

8 (453) 17

1

/

8 (308) 12

1

/

8 (1274) 54

5

/

8 (2834) 119½ (3035) 127

5

/

8 (2784) 117

7

/

8 (2562) 100

7

/

8 (2993) 112

3

/

8 (1380) 63½ (1612) 63½ (1612)

5

/

8 (803) 36

7

/

8 (453) 18

1

/

8 (2491) 96¼ (2444) 103

1

/

8 (308) 17

3

/

8 (1380) 63½ (1612) 63½ (1612)

5

/

8 (1413) 51

3

/

8 (2981) 125 (3176)

7

/

8 (2562) 122

7

/

8 (657) 25

5

/

8 (2861) 134

5

/

8 (929) 36

7

/

8 (479) 18

3

/

8 (440) 17

7

/

8 (1317) 61

1

/

8 (3230)

7

/

8 (5992)

3

/

8 (3107)

7

/

8 (657)

1

/

8 (3406)

5

/

8 (929)

7

/

8 (479)

7

/

8 (2639)

3

/

8 (440)

5

/

8 (1566)

13

Mechanical

Pyrotec Technical Data

Boiler Dimensions (continued)

a

Legend

A Boiler return
B Motor for de-ashing system (optional)
C Primary air blower 1
D Boiler supply

Dimensions

Boiler Model KPT- 390 530 720 950 1250

3

/

129

a in. (mm)

b in. (mm)

16 (3282) 149 (3782) 152

5

/

149

8 (3800) 169

5

/

16 (4300) 174

b

E Secondary air blower
F In-feed auger

5

/

8 (3877) 151 (3835) 172

9

/

16 (4434) 173 (4392) 194

1

/

2 (4380)

3

/

8 (4937)

Boiler Components

Legend

BS Boiler supply
BR Boiler return

A De-ashing system (optional)
B Cleaning cover, heat exchanger
C Combustion chamber temperature sensor
D Overpressure monitor
E Light barrier, fire box
F Igniter (optional)
G Cleaning cover trough
H Cleaning cover, external grate
K Light barrier de-ashing system
L Boiler door
M Pneumatic cleaning system
N Combustion chamber door
O Limit switch, combustion chamber door
P Primary air blower 2
Q Drive, in-feed grate
R Temperature sensor in-feed auger
S Limit switch, maintenance cover
T Light barrier, in-feed auger
U Extinguishing water connection
V Boiler drain and fill valve

14

5443 113 v1.9

Pyrotec Technical Data

Automatic De-ashing System

Mechanical

Preparation System for De-ashing

The trough for later incorporation of the de-ashing auger
is covered by refractory bricks.
The ash is removed manually via the firebox door.

De-ashing into ash bin, 63 USG (240 L)
De-ashing into ash bin, 211 USG (800 L)

The PYROTEC’s moving grate conveys the burnt-out ash
into an ash trough which is recessed deep in the refractory
floor. From there the ash is extracted from the boiler by
an auger made of heat-resistant steel.
An additional ascending conveyor auger moves the ash
into large-volume ash containers.
The galvanized ash containers connect easily to the ash
station by quick-action fasteners and move on rollers.

Pneumatic Cleaning System

Function of the control system:

A light barrier monitors the level of the ash level in the
troughtrough. When the level is exceeded, a certain
amount of ash is carried
off into the container.

The control system can be set to continuous operation
for cleaning purposes when the boiler is shut down.

Supplied with:

- Fire box auger made of heat-resistant steel

- Ascending conveyor auger with container station

- Ash bin

- Triggering system for the auger drives

- Infrared light barrier level monitoring system for ash in
fire box

Ash bin, 63 USG (240 L), spare
Ash bin, 211 USG (800 L), spare

Extension of ascending conveyor auger, per meter
Extension of firebox auger, per meter

Pneumatic cleaning system (for Pyrotec KPT-390)
Pneumatic cleaning system (for Pyrotec KPT-530 and –720)
Pneumatic cleaning system (for Pyrotec KPT-950 and –1250)

The complete heat exchanger is cleaned off by periodic
blasts of compressed air while the system is in regular
operation. During the cleaning process the individual
sections are blasted clean one after another. The ash on
the heat exchanger tubes is detached by very short but
strong blasts of air.

The particles detached are conducted by the flow of
gas to the de-duster, where most are filtered out and
collected.

The system is built into the boiler door.

The compressor should preferably be installed in a cool
spot in the heating room.

Function of the control system:

The number of cleaning cycles within one unit of time
(e.g. per hour) is adjusted according to the loading of the
furnace.
One single, complete cleaning cycle consists of one
sequence of blasts over all the sections of the heat
exchanger.

Supplied with boiler:

- Nozzle element built into the furnace door, including
connecting piece with heat dissipation plate

- Compressed air distributor with tank and valves; with
heat-resistant hoses connected to nozzle element

- Compressor; model IR-SS3L3, delivery capacity of 11.3
CFM / 0.32 m3/min; tank: 60 USG (227 L); pressure:
max. 135 psi; motor: 3 HP, 1200 RPM, 230V, includes
pressure controller, pressure switch and operating time
limiter; plug and play; noise level of normal design: 75 dBA

- Compressed air hose up to max. of 13 ft (4.0 m) in length

- Valves wired tight to terminal strip

- Software component in the control system

Customer supplied:

- Provide a power supply, 230V/ 16A

Technical data:

Boiler Model KPT- 390 530 720 950 1250

Number of zones/
valves

Size of valves

Max. air consumption,
full load USG/h (L/h)

The customer supplied air compressor has to deliver at
least the amount and quality of air specified and have
an adjustable pressure controller as well as a protective
device against hose rupture (e.g. operating time limiter).

8 10 12

1b” 1b” 1b”

819

(3100)

1162

(4400)

1400

(5300)

5443 113 v1.9

15

Mechanical

Flue Gas De-duster

Pyrotec Technical Data

The flue gas de-duster minimizes dust emissions and is
designed as a multi cyclone with axial function. The de­duster is fully insulated and has three covers for cleaning.
The crude gas chamber is cleaned via the side cleaning
cover. The clean gas chamber is cleaned via the upper
or back cleaning cover (unused blower connection).
The ash box has a carriage and is connected to the de­duster with quick-action fasteners. It can easily be pulled
out for emptying. The blower can be installed either on
the side or the top.

to the

from the
furnace

chimney

D

E

F

G

Supplied with:

- 1 flue gas de-duster

- 1 ash container 63 USG (240L) or 211 USG (800L)

CAUTION

The effects of heat can create dangerous conditions.

Legend

A Flue gas blower (with variable rotation)

- Either top or side

- Unused connection as cleaning cover

- Alternate mounting of the flue gas blower
(shown in dark grey)

B Flue gas temperature sensor
C Oxygen sensor
D Flue gas blower - choice of top or side - unused

connection as cleaning lid, variable rotation,
clean gas chamber

E Cleaning lid crude gas chamber
F De-duster (axial cyclone)

G Ash bin support frame 63 USG (240 L) or 211 USG (800 L)

G

from the
furnace

to the

chimney

Ash bin support frame: positioning is possible in 4 x 90
(extraction, ash container) Drawn with extraction to the right

Top

Top

Top

Boiler Model KPT- 390 530 720 950 1250

A in. (mm) 13¾ (350) 13¾ (350) 13¾ (350) 15¾ (400) 17

7

a in. (mm) 81
c in. (mm) 92

/

8 (2080) 92

7

/

8 (2359) 92

j in. (mm) 125½ (3186) 125½ (3186) 133 (3378) 135

3

k in. (mm) 52

/

8 (1330) 52

l in. (mm) 49½ (1256) 49½ (1256) 49½ (1256) 51

5

m in. (mm) 23

n in. (mm) 17
q in. (mm) 49

/

8 (600) 23

5

/

8 (447) 17

5

/

8 (1260) 49

7

/

8 (2359) 98

7

/

8 (2359) 98

3

/

8 (1330) 57

5

/

8 (600) 26 (660) 27

5

/

8 (447) 18

5

/

8 (1260) 49

1

/

16 (2491) 96¼ (2444) 103

1

/

16 (2491) 96¼ (2444) 103

9

/

16 (1462) 57

1

/

8 (461) 22

5

/

8 (1260) 40

7

/

8 (3452) 146

9

/

16 (1462) 65¼ (1657)

3

/

16 (1300) 51

1

/

8 (690) 30 (760)

7

/

8 (579) 22

1

/

8 (1020) 40

r in. (mm) 24½ (620) 24½ (620) 24½ (620) 37½ (950) 37½ (950)
t in. (mm) 65¾ (1670) 65¾ (1670) 68 (1730) 82 (2083) 84¾ (2153)

16

11

/

16 (450)

7

/

8 (2639)

7

/

8 (2639)

3

/

8 (3717)

3

/

16 (1300)

7

/

8 (579)

1

/

8 (1020)

º

5443 113 v1.9

Pyrotec Technical Data

Safety Devices

The boiler system with return 3-way valve

To reliably prevent boiler corrosion through condensation
of the flue gases, the boiler return flow temperature must
never be below 149° F (65° C).

The stepless control of the PYROTEC Grate Firing System
output requires a constant flow through the boiler of the
water to be heated. The boiler circuit, the boiler pump and
boiler-mixing valve must therefore be installed according
to section piping and installation of safety devices.

The boiler circuit should be designed that the temperature
difference between the boiler supply and the boiler return
temperature is equal to or less than 27° F (15° C).

The activation of the boiler pump and boiler mixing valve
is integrated in the custom control panel.

The safety equipment for the heating installation must be
installed by a heating contractor authorized to do so.

Mechanical

Legend

A Nipple, c in. x 1b in.
B Reducing coupling, c in. x b in.
C Boiler water temperature gauge
D Bushing c in. x a in.
E Nipple a in. x 2b in.
F Ball valve a in.
G Pressure gauge
H Sensor well - Safety Temperature Limiter (STB)

(sensor supplied)

I Safety heat exchanger connections, NPTM b in.
J PRV Pressure Relief Valve connection cap
K Reducing bushing
L Nipple
M Pressure relief valve, 30 psi or 60 psi
N Reducing bushing (KPT 1250, 30 psi only)
O Nipple (KPT 1250, 30 psi only)

2

1

G

C

F

I

E

B

D

H

T

I

A

S

U

1

See section Piping and Installation of Safety Devices

2

Two PRVs must be installed on the KPT 1250 ­ 30 psi boiler. One PRV must be installed and the
other PRV connection must be capped on the
KPT 1250 - 60 psi boiler. All other models have
only one PRV connection.

3

4 in. boiler flange for Pyrotec 390-720, 6 in. boiler
flange for Pyrotec 950-1250

M

L

K

P

O

Q

R

I

N

J

I

P Pressure relief valve, 30 psi or 60 psi

(KPT 1250, 30 psi only)
Q 4 in. or 6 in. Boiler supply flange

3

R Supply sensor well (sensor supplied)
S 4 in. or 6 in. Boiler return flange

3

T Return sensor well (sensor supplied)
U Sensor wells for thermal safety flush valve (Rb in.)

(sensor supplied)

Note: All fittings shown and sensors indicated are
factory supplied. The size and quantity are
matched to the specific boiler model.

5443 113 v1.9

17

Mechanical

Piping and Installation of Safety Devices

Drain
inspection
port

Pyrotec Technical Data

System fill

Safety heat exchanger top view

4 heat
exchanger
loops and
2 TS2430
for Pyrotec
720, 950
and 1250

Legend

A Additional heat source
B Storage tank as low loss header (option A, 5 sensors)
C Distributor, heat consumer
D Storage tank #1
E Storage tank #2

F Two storage tanks as low loss header (option B,

5 sensors)

System fill

3-Way mixing valve

System return line

Blocked

port

Boiler return line

1, 2 and 3 indicates system connections

Adjustment

Bypass line

Valve adjustment must
be facing forward

18

5443 113 v1.9

Pyrotec Technical Data

Piping and Installation of Safety Devices (continued)

Mechanical

Note: To reliably prevent boiler corrosion caused by
condensation of flue gases, the boiler return flow
temperature must not under any circumstances be
below 150° F (65° C).
A Viessmann sized boiler pump with a boiler mixing
valve are provided according to the tables below.
The boiler circuit should be designed such that the
temperature difference between the supply and the
return temperature is equal to or less than ∆t 27° F
(15° C).
The expansion tank has to be connected to the
boiler without any shut-offs.

Safety equipment supplied by Viessmann:

- M 20 Boiler pump

- Y 20 Boiler mixing valve

- PRV Pressure relief valve, pressure set to 30 or 60 psi

- TS2430 Thermal run-off safety valve R ¾ in., approved
component; special-purpose, designed for opening at
a temperature of 122°- 248° F (50°- 120° C), (safety
heat exchanger loop built into boiler). The Pyrotec 390
and Pyrotec 530 have two safety heat exchanger loops
and require one thermal run-off safety valve.
The Pyrotec 720 to Pyrotec 1250 have four safety heat
exchanger loops and require two thermal run-off safety
valves.

- LWCO Low water cut-off

- PG Pressure gauge

- TG Temperature gauge (thermometer)

- SHE Safety heat exchanger, water volume 1.1 USG
(4.2L) per loop, NPTM b in.

Customer supplied:

- PDP Pressure relief valve drain pipe

- DCW Cold water inlet, min. 36 psi (2.5 bar), max.
51 psi (3.5 bar)

- AV Air separator / vent

- EXP Expansion tank closed;

- for safety heat exchanger required (size according
to volume of safety heat exchanger loops and volume
of piping

- for heating system (optional)

- WSL Water supply line for safety heat exchanger

- WLV Water supply line for thermal run-off safety valve

- SDP Safety heat exchanger drain pipe

- SRL System return line to the boiler from the system

- SSL System supply line from the boiler to the system

- BPL Bypass line

- BR Boiler return

- BS Boiler supply

Note: The KPT 1250, 30 psi will have 2 PRVs.

Design Recommendation:

Thermal run off safety valve

Boiler Model KPT- Thermal run-off

safety valve

TS-2430

(Quantity)

Water through-

put required at

36 psi

(2.5 bar)

Supply line

WSL

L/h GPM

390 1 1637 7.2

530 1 2224 9.8

R c in. R c in.

R c in. R c in.

720 2 3020 13.3 R 1 in.

950 2 3986 17.6 R 1 in.

1250 2 5246 23.0

R 1a in. R c in.

Pressure relief valve

Boiler model KPT- Pressure relief valve Conbraco

1

30 psi 60 psi 30 psi 60 psi

390

530

1a in.

1b in. 1a in.

720 2 in.

950 2 in.

1 in.

1a in. 2b in. 1b in.

1b in. 2b in.

1250 2 in. 2 in.

Supply line

WLV

Drain pipe

SDP

R 1 in.

R 1 in.

R c in.

R c in.

R 1 in.

R 1 in.

R 1 in.

Drain pipe PDP

2

1b in. 1a in.

2 in.

1b in.

2 in.

2b in.

2 in.

2

1

Threaded connection for supply line

2

Length of the drain pipe up to 13 ft. (4.0 m)

5443 113 v1.9

19

Mechanical

Pyrotec Technical Data

Piping and Installation of Safety Devices (continued)

Design Recommendation (continued):

Boiler Pump

Boiler model KPT- Pump Frequency Voltage and phase

390 UPS 50-80/4 F 60 Hz 3 x 208-230 V

530 UPS 50-80/4 F 60 Hz 3 x 208-230 V

720 UPS 80-160 F 60 Hz 3 x 208-230 V

950 UPS 80-160 F 60 Hz 3 x 208-230 V

1250 TP 100-80/4 60 Hz 3 x 208-230 / 460 V

Mixing valve

Boiler model KPT- Nominal

pipe size

390 3 in. 3-way mixing valve
530 4 in. 3-way mixing valve
720 5 in. 3-way mixing valve
950 5 in. 3-way mixing valve

1250 6 in. 3-way mixing valve

Valve

Fire Protection

Follow local regulations for wood-fired heating systems.

Power failure provision

The customer 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 run-off safety valve.

Protection against back-burn for the boiler plant

The following safeguards are part of the scope of
delivery for the PYROTEC Grate Firing System:

- Preventing overfilling of the fire box

A level monitor must be installed to prevent overfilling
of the fire box. The PYROTEC Grate Firing System
has a light barrier to monitor the embers.

- Preventing back-burn

With a temperature sensor directly on the in-feed auger,
any danger of back-burn initiation will be detected and
quickly counteracted at an early stage by increasing the
fuel conveyance speed into the fire box.

- Back flash safeguard

The PYROTEC Grate Firing System is operated with
continuous negative pressure and is equipped with
a back flash prevention device. This device prevents
back flashes caused by flying embers or combustible
gases that may ignite the fuel system.

Viessmann ASME recommended tank sizes (U-stamped)

Boiler model KPT- Tank size

L USG

390 3785 1000
530 5678 1500
720 6624 1750
950 9464 2500

1250 12492 3300

- Automatic in-feed auger extinguishing system

The supplied fire extinguishing system is necessary on
the in-feed auger. This system should reliably prevent
back- burn in case of a malfunction (such as a power
failure). For safety reasons and to prevent damage by
flooding, connecting the extinguishing system directly
to the water network is not advisable.

This extinguishing system must be equipped with a

6.6 USG (25 L) extinguishing water tank with a float­ type switch and an adjustable Danfoss extinguisher
valve. The tank for the extinguishing system must be
equipped with a level monitoring system.

If there is a shortage of water, the PYROTEC Grate
Firing System will switch off automatically.

In case of excess temperature, the in-feed auger will
be flooded reliably but in a limited fashion.

IMPORTANT

The heating contractor must perform the installation of
the fire extinguishing system as specified in section Fire
Extinguishing Systems.

20

5443 113 v1.9

Pyrotec Technical Data

Fire Protection (continued)

Mechanical

Back-burn safeguard for the fuel supply system

The fire extinguishing system for the conveyor auger and
the down pipe depends on specific requirements (location,
size of the fuel storage site, material, pressure conditions
and regulations), these being accessories to the scope
of delivery ordered from Viessmann according to their
descriptions.

Automatic triggering system for the fuel supply system

Approved in part as a variation to the shut-off valve in
pressure-less fuel storage units.

Slide valve

The slide valve is approved in pressure-less fuel storage
units and is a suitable safeguard against back-burn.
The slide valve is optional and closes in case of standstill,
danger of back-burn, or power failure with the help of a
spring return motor.

IMPORTANT

We recommend installing a rotary valve for the PYROTEC
Grate Firing System. In addition to being a safeguard
against back-burn, this will also prevent any penetration
by air leaking in via the in-feed auger.

Rotary valve

The rotary valve is optional and used if remnant wood
is moved into fuel storage spaces with blowers, then, in
order to reduce pressure applied, at least one rotary valve
is necessary to reduce pressure between the fuel storage
unit and the boiler. The rotary valve is suited to reduce
pressure and at the same time is considered a suitable
safeguard against back-burn.

Max. overpressure allowed in fuel storage unit:
+500 Pa / +2.00”wc.

Max. negative pressure allowed in fuel storage unit:

+0 Pa / +0”wc.

Double rotary valve with pressure compensation system

If, due to special circumstances, any mechanically
produced negative pressures or extraordinarily high
overpressures are expected in the fuel storage unit,
then two rotary valves must be installed in the material
transport route according to the respective project plan
with a pressure compensation line to the outdoors.

Max. overpressure allowed in fuel storage unit:

+3000 Pa /+12”wc.

Max. negative pressure allowed in fuel storage unit:

-3000 Pa / –12”wc.

IMPORTANT

The supplier of the silo must confirm the maximum weight
that is to be expected on the rotary valve.

The rotary valve below the silo extraction system can
become leaky due to wear of the sealing elements or
through large pieces of wood that cannot be conveyed.
This leakage can make it possible for low-temperature
gases to flow back from the boiler into the silo.

A smoke alarm must be installed between the rotary
valve and the silo extraction system, which, when
triggered, will disconnect the system and create negative
pressure in the silo.

Down pipe

A vertical drop-off section interrupts the connected line
of burning material.

Fire protection for fuel storage space

Viessmann does not provide fire protection for the fuel
storage space.

IMPORTANT

The local building codes and regulations must be followed
by the heating contractor.

5443 113 v1.9

21

Mechanical

Fire Extinguishing System

Pyrotec Technical Data

The fire extinguishing system functions independent from
the electrical power and is flooding the material which is
still remaining in the in-feed auger in case of back-burn.
The activation temperature is approximately 200° F (95° C)

Fire extinguishing system for the in-feed auger

Note: The fire extinguishing system for the in-feed auger

is part of the boiler.

- Line from the extinguishing water container to the b in.
valve (as short as possible).

- Valve thermostatic, Danfoss AVTA 15 122° F-194° F
(50°- 90°C) position 3 equals approximately
176° F (80° C).

- The lines must be executed as hard piping in metal (b in.).

- It must not be possible to shut off the cold water inlet
without the aid of tools.

- Be especially sure to comply with the instruction in the
Fire Protection section.

Fire extinguishing system for the down pipe

Note: The fire extinguishing system for the down pipe

is optional.

Note: A slide valve is required as standard for an unpressurized
material store or a rotary valve for a material storage
with overpressure or underpressure (charging with
blower, e.g. wood processing operations).

The lines must be executed as hard piping in metal (b in.).
It must not be possible to shut off the cold water inlet
without the aid of tools. Be especially sure to comply with
the instruction in the Fire Protection section.

Fire extinguishing system for the conveyor auger

Note: The fire extinguishing system for the conveyor

auger is optional.

Legend

A Combustion
B Metering Container
C Fuel supply
D Extinguishing water container 6.6 USG (25 L)
E N25 floater switch

CW Cold water supply b in. min. 30 psi (2.0 bar),
max. 45 psi (3.0 bar)

22

5443 113 v1.9

Pyrotec Technical Data

Vitocontrol

Electrical

Mounting of the control panel

The control panel should be in an area where the heat
radiation (front side of boiler, rear side of boiler with flue gas
de-duster and flue gas blower as well as recirculation line)
and the exposure to dust during cleaning is at a minimum.

The ambient temperature for the control panel approx.
4 in. (100 mm) away from the control cabinet) should not
exceed 104° F (40° C) while the system is in operation.
The minimum temperature must not be less than 50° F
(10° C) In case of doubt, preference should be given to
placing the control panel outside the mechanical room near
the heating room door.

Electrical connection

- Install the control panel according to the field wiring
diagram. The field wiring diagram is supplied with the
control panel.

- In the area of hot parts (flue gas blower, flue gas pipe),
the lines should be installed in steel pipes at an
appropriate distance so as to be protected from
excessive temperatures. See section Boiler Wiring.

- The cable bushings to the motors and equipment must
be dust-tight and provided with a strain relief.

An SPS-control system for the complete PYROTEC Boiler Plant,
including control of the fuel loading systems required for
the separately listed items. The heat output of the boiler
adjusts to the heat consumption in modulating fashion.
A regulating circuit for the combustion optimizing system
is superimposed on the output control circuit with a
lambda sensor. Maximum quality criteria are met in terms
of fire protection and personal protection.

Functions:

- Output and control circuits with modulating output
operation (25%-100%)

- Air-conducted by means of a speed-regulated supply
air fan, depending on the supply temperature

- Precise re-supplying of fuel by the in-feed auger from
the metering container with an insulating layer

- Refilling of the metering container with the use of a
level monitoring system

- Limitation and distribution of the mass burning in the
fire box by means of a level monitoring system in the
fire box along with movement of the feed grate

- Emissions-optimized control circuit with fine-tuning of
the fuel/air mixture by a lambda sensor

- Pressure regulation of the fire box with constant
negative pressure guaranteed

- Fire box temperature limitation with the required
variation of the air index to protect the fire-resistant lining

- Upholding the return temperature with the boiler
mixing valve provides for a long service life of the boiler.

Safety functions for:

- Excess temperature, burn-back, opening of the fire box
door, opening of a lid in the loading system, excess
pressure in the fire box

- Floating output (malfunction combustion system)

Operation:

Operation is carried out by means of a control panel with
a membrane keyboard and plain language display, which
are built into the control cabinet door. All the operational
data can be read on the display. The set points for all the
important parameters can be entered simply using the
keyboard. Malfunctions are displayed in plain language
and indicated in the order of their occurrence.

Supplied with:

- Control cabinet (uninstalled), surface powder-coated
with RAL 7035 (gray) textured, executed according
to CSA C.22, ready-wired on series terminals,
Power supply: 208V/3/60Hz; control voltage: 120 /
240V/1/60Hz or 24 V

- Adapted, updateable software

- Soft starter for all the drives for the loader system
(208V/3/60Hz) according to the accessories

- Overload protection for boiler pump

- Outputs for stepping motors

- Variable frequency drive (EMC-Operation Class 3)
for exhaust fan

- Main disconnect

- Documentation, including bound circuit diagram,
terminal connection diagram with cable designation,
operating and maintenance instructions, installation
instructions in document pocket

- Sensors and switches for in-feed auger

- Infrared light barrier level monitoring system,
insulating layer for feed auger

- Safety limit switch on the maintenance lid for the
in-feed auger

- Temperature sensor for the in-feed auger

- Sensors and switches on the fire box for firing
and in the exhaust gas nozzle (installation on site)

- Infrared light barriers for level monitoring of fuel in
the fire box

- Zirconium dioxide sensor with instrument reading
converter (lambda sensor)

- Exhaust gas temperature sensor

- Sensors and switches mounted on the boiler on top

- Sensor in the connecting piece, supply flow

- Sensor in the connecting piece, return

- Sensor, uninstalled

- One sensor with sensor well, 1/2“ x 280 mm

5443 113 v1.9

23

Electrical

Vitocontrol - Accessories

Pyrotec Technical Data

Note: The control system components below are
reserved for the PYROTEC Single-unit System.
With the PYROTEC Double-unit System, these
functions are included in the PYROTEC Mastercontrol.

Hot Water Storage Tank Management System, 5 Sensors

Function:

Using a heat accumulator improves the modulating output
operation of the PYROTEC grate firing system. In addition,
sudden heat requirement peaks are covered. The accumulator’s
load of heat is detected by the temperature sensors. The
degree to which the accumulator is loaded is determined
by the external temperature sensor. The firing power is
adapted to the accumulator’s degree of loading.

Supplied with:

- 4 additional PT100 sensors with sensor well,
1/2” x 280 mm

- 1 outdoor temperature sensor, uninstalled

Output signals 0 - 10 V

Function:

The system includes output of the boiler in the form of a
voltage signal and preparation for connection to receive a
maximum limitation of the boiler output.

Supplied with:

- Output of the boiler, 0 - 10 V

- Reception and processing of an external output limitation

0 - 0.5 V..... OFF

0.6 - 3 V..... Maintain embers

3.1 - 10 V... 30% to 100% output operation

Note: Installation of “Output signals 0 - 10 V” is possible
according to irrespective of any additional control
system components to be used.

Operational Message

Function:

System status “Operating Load” indication; from
operation of the boiler pump to higher-level control.

Supplied with:

- Floating output (operational message)

Export System for Operational Data

Function:

Output of all relevant operational data and error reports for
the PYROTEC Boiler Plant via MOD-BUS in the form of an
ASCII-data record via serial interface to higher-level control
equipment of the customer’s. All the adjustable parameters
can be changed via the higher-level control equipment as
long as the control equipment provides for this.

Supplied with:

- Interface on the control panel

- Software component

- MOD-BUS protocol (baud rate 9600)

Visualization by web server

Function:

A complete package for transmitting all data to a remote
computer for visualization, remote maintenance and
archiving of operational data for the PYROTEC Boiler
Plant. The hardware and software are integrated in the
Vitocontrol control system. All the adjustable parameters
can be changed from the remote computer.

Customer supplied:

- IP address configuration

Electrical Components

24

5443 113 v1.9

Pyrotec Technical Data

Electrical Components (continued)

M High voltage B sensors N Sensors
Y Low voltage S Switches

High Voltage
Number Designation Device tag Description

1 M1 -3M1 Exhaust blower (not shown)
2 M11 -9M11 Grate drive
3 M13 -13M13 Secondary air blower (not shown)
4 M14 -14M14 De-ashing auger
5 M15 -15M15 De-ashing ascending conveyor auger (not shown)
6 M16 -16M16 Ignition blower (not shown)
7 M20 -17M20 Boiler pump (not shown)

Low Voltage

8 Y20 -18Y20 Mixing valve actuator (not shown)

9 Y71 -20Y71 Solenoid valve 1
10 Y72 -20Y72 Solenoid valve 2
11 Y73 -20Y73 Solenoid valve 3
12 Y74 -20Y74 Solenoid valve 4
13 Y75 -20Y75 Solenoid valve 5
14 Y76 -20Y76 Solenoid valve 6
15 Y77 -20Y77 Solenoid valve 7
16 Y78 -20Y78 Solenoid valve 8
17 Y79 -20Y79 Solenoid valve 9
18 Y80 -20Y80 Solenoid valve 10
19 Y81 -20Y81 Solenoid valve 11
20 Y82 -20Y82 Solenoid valve 12

Electrical

Temperature sensors

21 B1 -107B1 Flue gas temperature sensor (not shown)
22 B20 -107B20 Boiler supply temperature sensor
23 B20.1 -107B20.1 Boiler return temperature sensor
24 B27 -73B27 Fire box temperature sensor (not shown)

Light barriers

25 B1G/1 -61B1G/1 Light barrier embers (Transmitter) (not shown)
26 B1G/2 -61B1G/2 Light barrier embers (Receiver) (not shown)
27 B2/1 -61B2/1 Light barrier in-feed auger (Transmitter)
28 B2/2 -61B2/2 Light barrier in-feed auger (Receiver)
29 B14/1 -61B14/1 Light barrier de-ashing auger (Transmitter)
30 B14/2 -61B14/2 Light barrier de-ashing auger (Receiver)

Sensors

31 B26 -91B26 O2 sensor (not shown)
32 U26 -91U26 O2 sensor transducer (not shown)
33 N25 -69N25 Floater switch for fire extinguishing water container (not shown)
34 N21 -72N21 Safety temperature limiter STL (not shown)
35 U1 -17U1 Low water cut-off (not shown)
36 N23 -72N23 Water safety pressure switch (not shown)

37 S1 -60S1 Limit switch for the fire box door
38 B70 -67B70 Differential pressure transmitter for the fire box (not shown)
39 N70 -72N70 Pressure switch for the fire box RAK (not shown)

5443 113 v1.9

25

Electrical

Fuel Transport and Extraction Systems

Rotary Valve

Pyrotec Technical Data

Number Designation Device tag Description

A

26

M9 -9 M9 Motor for rotary valve

5443 113 v1.9

Pyrotec Technical Data

Fuel Transport and Extraction Systems

In-feed auger

Number Designation Device tag Description

40 M2 -4M2 Motor for in-feed auger

41 S2 -68S2 Limit switch for maintenance lid

42 B31.1 -11B31.1 Light barrier metering container (Transmitter)

43 B31.2 -11B31.2 Light barrier metering container (Receiver)

44 M10.1 -8M10.1 Slide valve T30

45 M10.2 -8M10.2 Slide valve T30

46 B02 -107B02 In-feed auger temperature sensor

Electrical

Note: For details on designation see field wiring diagram.

Pipe/trough conveyor auger

Number Designation Device tag Description

47 M4.1 -5M4.1 Motor for pipe/trough conveyor auger

48 S4.1 -68S4.1 Limit switch for maintenance lid

49 B4.1/1 -61B4.1/1 Light barrier conveyor auger (Transmitter)

50 B4.1/2 -61B4.1/2 Light barrier conveyor auger (Receiver)

Note: For details on designation see field wiring diagram.

5443 113 v1.9

27

Electrical

Fuel Transport and Extraction Systems (continued)

Pellet extraction auger

Number Designation Device tag Description

51 M32 -12M32 Motor for pellet extraction auger

52 S32.1 -12S32.1 Limit switch for maintenance lid

53 S32.2 -12S32.2 Limit switch for silo door (not shown)

Pyrotec Technical Data

Note: For details on designation see field wiring diagram.

Spring extraction system

Number Designation Device tag Description

54 M32 -12M32 Motor for spring extraction system

55 S32.1 -12S32.1 Limit switch for maintenance lid

56 S32.2 -12S32.2 Limit switch for silo door (not shown)

Note: For details on designation see field wiring diagram.

28

5443 113 v1.9

Pyrotec Technical Data

Fuel Transport and Extraction Systems (continued)

Horizontal extraction system

Electrical

Number Designation Device tag Description

57 M32 -12M32 Motor for extraction auger

58 M33 -12M33 Motor for agitator

59 B32 -12B32 Light barrier for extraction auger

60 S32.1 -12S32.1 Safety switch for maintenance lid

61 S32.2 -12S32.2 Safety switch for silo door (not shown)

Note: For details on designation see field wiring diagram.

5443 113 v1.9

29

Electrical

Fuel Transport and Extraction Systems (continued)

Walking floor auger

Number Designation Device tag Description

62 M2 -4M2 Motor for walking floor auger

63 S3 -68S3 Safety switch for maintenance lid

64 S3.1 -68S3.1 Safety switch for auger cover

65 B3/1 -61B3/1 Light barrier walking floor auger (Transmitter)

66 B3/2 -61B3/2 Light barrier walking floor auger (Receiver)

67 B6.1/1 -61B6.1/1 Light barrier silo distribution top (Transmitter)

68 B6.1/2 -61B6.1/2 Light barrier silo distribution top (Receiver)

69 B6.2/1 -61B6.2/1 Light barrier silo distribution bottom (Transmitter)

70 B6.2/2 -61B6.2/2 Light barrier silo distribution bottom (Receiver)

Note: For details on designation see field wiring diagram.
Note: Items 67 to 70 only apply to the walking floor with filling function.

Pyrotec Technical Data

Hydraulic unit

Number Designation Device tag Description

71 M6 -7M6 Motor for hydraulic unit

72 Y6.1 -25Y6.1 Solenoid valve to change between silo lid and walking floor

73 Y6.9 -7Y6.9 Change silo distribution

74 N6.1 -7N6.1 Hydraulic temperature

75 N6.2 -7N6.2 Hydraulic level

Note: For details on designation see field wiring diagram.
Note: Items 72 and 73 are optional.

30

5443 113 v1.9

Pyrotec Technical Data

Fuel Transport and Extraction Systems (continued)

Silo Lid

Number Designation Device tag Description

76 Y6.3 -22Y6.3 Solenoid valve silo lid open

77 Y6.4 -22Y6.4 Solenoid valve silo lid close

78 S6.1 -22S6.1 Key operated switch for silo lid

79 M901 -24M901 Vibration motor 1

80 M902 -24M902 Vibration motor 2

81 M903 -24M903 Vibration motor 3

82 S901 -24S901 Key operated switch for vibration motor

83 S5.1 -68S5.1 Safety switch for silo lid

Note: For details on designation see field wiring diagram.
Note: The quantity of items 79 to 81 will depend on the size of the silo lid.

Hot Water Storage Tank

Hot water storage tank

Electrical

Number Designation Device tag Description

84 B28.1 -109B28.1 Hot water storage tank sensor (top)

85 B28.2 -109B28.2 Hot water storage tank sensor (top/middle)

86 B28.3 -109B28.3 Hot water storage tank sensor (middle)

87 B28.4 -109B28.4 Hot water storage tank sensor (middle/bottom)

88 B28.5 -110B28.5 Hot water storage tank sensor (bottom)

89 B60 -110B60 Outdoor temperature sensor (not shown)

Note: For details on designation see field wiring diagram.

5443 113 v1.9

31

Commissioning

Fuel for the commissioning

For the commissioning, sufficient dry fuel (max. W 20%)
should be stored for approx. 10-24 full operating hours:

PYROTEC 390 approx. 5100 lb.
PYROTEC 530 approx. 6600 lb.
PYROTEC 720 approx. 8800 lb.
PYROTEC 950 approx. 11660 lb.
PYROTEC 1250 approx. 14960 lb.

Since the boiler plant will be cold, and residual moisture
will be drawn from the refractory concrete during the
initial operation, the material to be burned for the initial
operation has to be at least air dry. For the first three hours,
the heating-up process should be carried out at low output.

To ensure that the silo extraction system is functioning
properly, only place a minimal amount of fuel in the silo
in case there is a problem. This enables the extraction
system to be cleaned out quickly and the problem to be
identified and corrected.

Pyrotec Technical Data

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