Tarm Biomass Bonus Plus 30 User manual

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14
Bonus Plus
Model 30
Installation and Operations Manual
Wood-fired central heating boiler
Report #236-S-09-2
UL 2523-2009 (R2013) “Solid Fuel-Fired Hydronic Heating Appliances, Water Heaters, and Boilers.”

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 3
Table of Contents
Section.....................................................................................................................................page
1.0 Introduction.......................................................................................................................4
1.1 Foreword .....................................................................................................................4
1.2 Units of Measure .........................................................................................................4
1.3 Installation and Warranty Requirements.....................................................................4
2.0 Product Description and Requirements for Safe Operation..............................................6
2.1 Boiler Overview ..........................................................................................................6
2.1.1 Boiler Cutaway View.........................................................................................6
2.1.2 Boiler Control Panel ..........................................................................................7
2.2 Boiler Function............................................................................................................7
2.2.1 General Operation..............................................................................................7
2.2.2 Description of Burn Process ..............................................................................8
2.2.3 Safety Systems ...................................................................................................9
2.2.4 Accessories ........................................................................................................9
2.2.5 Boiler Fabrication and Testing...........................................................................10
2.2.6 Models and Applications ...................................................................................10
2.3 Fuels ............................................................................................................................10
2.4 Building Requirements................................................................................................12
2.5 Owner Responsibilities ...............................................................................................12
3.0 Boiler Installation and Start-up.........................................................................................13
3.1 Planning.......................................................................................................................13
3.1.1 Sizing the Boiler ................................................................................................13
3.1.2 Choosing an Installer .........................................................................................13
3.1.3 Locating the Boiler and Clearances ...................................................................13
3.1.4 Plumbing and Mechanical..................................................................................15
3.1.5 Electrical ............................................................................................................16
3.2 Preparing the Chimney................................................................................................16
3.2.1 Outside Combustion Air ....................................................................................18
3.3 Setting the Boiler.........................................................................................................18
3.3.1 Receiving the Boiler ..........................................................................................18
3.3.2 Temporary Storage.............................................................................................19
3.3.3 Moving the Boiler ..............................................................................................19
3.3.4 Boiler Set-up ......................................................................................................19
3.4 Connections to the Boiler............................................................................................19
3.4.1 Chimney Connection .........................................................................................19
3.4.2 Safety Plumbing.................................................................................................20
3.4.3 System Plumbing ...............................................................................................21
3.4.4 Pipe Connection-Choice of Material .................................................................21
3.4.5 Immersion Tubes and Wells ..............................................................................21
3.4.6 Expansion Tank .................................................................................................21
3.4.7 Pump Size ..........................................................................................................21
3.4.8 Installing the Circulator Aquastat ......................................................................21
3.4.9 Installing the Overheat Aquastat........................................................................22
3.4.10 Installing the 339N Probe Thermometer..........................................................23
Table Of Contents

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 4
Table Of Contents
Section.....................................................................................................................................Page
3.4.11 Electrical Connections .....................................................................................23
3.5 Commissioning the Boiler ..........................................................................................23
3.5.1 Safety Plumbing.................................................................................................23
3.5.2 Filling and Venting ............................................................................................24
4.0 Boiler Operation, Maintenance, and Service ...............................................................25
4.1 Control Panel Orientation. ..........................................................................................25
4.2 Items to Check Before Using......................................................................................28
4.3 Boiler Lighting / Starting Process...............................................................................28
4.4 Adding Wood to an Already Established Fire ............................................................29
4.5 Daily Firing.................................................................................................................29
4.6 Shutting Down the Boiler ...........................................................................................29
4.7 Operation with Thermal Storage System....................................................................29
4.8 Creosote ......................................................................................................................30
4.9 Adjusting Combustion ................................................................................................30
4.10 Cleaning and Maintenance........................................................................................31
4.10.1 Removing Ash .................................................................................................31
4.10.2 Cleaning the Induction Fan..............................................................................34
4.10.3 Maintaining Door Seals ...................................................................................36
4.10.4 Cleaning the Primary Air Channels .................................................................36
4.10.5 Smoke Pipe Inspection and Cleaning ..............................................................38
4.10.6 Chimney Fires..................................................................................................38
4.10.7 Checking the Barometric Damper ...................................................................39
4.10.8 Cleaning the Jacket ..........................................................................................39
4.10.9 Check for Creosote Build-up ...........................................................................39
4.10.10 Seasonal Shutdown Procedure.......................................................................39
4.10.11 Checking the Pressure Relief Valve ..............................................................39
4.10.12 Checking System Pressure.............................................................................39
4.10.13 Heat Storage System Maintenance ................................................................39
4.11 Power Outages ....................................................................................................39
5.0 Troubleshooting ..............................................................................................................40
5.1 Troubleshooting Guide ...............................................................................................40
6.0 Data and Drawings .........................................................................................................42
6.1 Measurement Data ......................................................................................................42
6.2 Positioning Data..........................................................................................................43
6.3 Specification Data.......................................................................................................44
6.4 Electrical Diagrams.....................................................................................................45
6.4.1 Wiring Diagram A (Boiler Circuit Ladder Diagram) ........................................45
6.4.3 Circulator and Overheat Aquastat Wiring Connections ....................................46
7.0 Warranty Information....................................................................................................47
7.1 HS-Tarm Bonus Plus Wood Boiler Warranty .......................................................47
8.0 Installation Report for Boiler System ...........................................................................49
Appendix A-Temperature Conversion ...............................................................................50
Appendix B- Contact Information ......................................................................................51
Appendix C–Quick Start Guide .........................................................................................52

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 5
1.0 Introduction
1.1 Foreword
SAVE THIS INSTRUCTION MANUAL FOR FUTURE REFERENCE
Congratulations on your purchase of the HS Tarm Bonus Plus log wood boiler from
Tarm Biomass!
The Bonus Plus boiler is produced using the highest quality materials and a modern production sys-
tem. The use of high technology laser cutting and robotic welding system, accompanied by time hon-
ored European design, craftsmanship and attention to detail, results in a long lasting boiler with un-
matched fit and finish.
With proper installation, operation and maintenance your Tarm Biomass Bonus Plus log wood boiler
will provide years of safe, dependable, economic and earth friendly heating.
This manual contains paragraphs that require your special attention. These paragraphs are marked
with the symbols described below:
Warning: there is a risk of an accident of personal injury or serious damage to the property.
☼Caution: there is a risk of damaging the boiler or its individual components.
1.2 Units of Measurement
Most hardware and fittings on the boiler are metric (all plumbing fittings are British Straight Thread).
In this manual the convention used for dimensions is that values are presented in English units, fol-
lowed by metric units in parenthesis, for example: 6” (152 mm).
Note: A conversion table between Centigrade and Fahrenheit is provided in Appendix A. In this
manual temperatures are presented first as degrees Centigrade then as degrees Fahrenheit in parenthe-
sis, for example: 80 °C (176 °F).
1.3 Installation and Warranty Requirements
It is strongly recommended that the installer resist the temptation to simply get started without reading
this manual. Hours of time and frustration can be prevented by a simple understanding of this product.
This manual has been written with much care and thought. We want the first time installer to find in-
stallation as simple as for the experienced installer. Time spent reading now will save more time in the
long run.
The Bonus Plus boiler must be installed with a thermal storage system capable of absorbing the
complete output of the boiler during periods when the building is not calling for heat. A means
for protecting the boiler against cold return temperatures must also be provided. Further infor-
mation on acceptable ways of meeting these warranty requirements is provided in Section 3.0,
Installation.
Introduction > Foreword

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 6
This product is provided with a limited warranty which is described in Section 7.0 of this manual. The
warranty is contingent upon the successful and legal installation of the boiler. At a minimum, the in-
stallation, adjustment, start up, service, and maintenance of this product must be performed by a li-
censed professional heating system installer. Where applicable, the installation must be inspected and
accepted by the legally responsible entity. Conditions described in the text of the warranty for keeping
it in force must be followed by the owner/ system operator.
If the boiler has been purchased through a dealer, the warranty claim must be made to the dealer. Oth-
erwise, claims may be made directly to Tarm Biomass.
Please read the literature enclosed by the manufacturer regarding the various accessory devices. These
devices are warranted by the manufacturer, NOT BY Tarm Biomass These accessory devices must be
installed and used according to the recommendations of the manufacturer.
Failure to follow these instructions could result in property damage, bodily injury, or death. All boilers
must be installed in accordance with national, state, and local plumbing, heating, and electrical codes
and the regulations of the serving electric, water, and gas utilities. Contact local building or fire offi-
cials before installation about restrictions and installation inspection requirements in your area. This
boiler is safety tested and listed. The Bonus Plus boiler does not carry an ASME stamp.
The instructions in this manual and in supporting documentation (additional instructions, diagrams,
and component information provided by Tarm Biomass) must be followed. If the instructions are in
conflict with local code requirements, the local code requirements will prevail. When in doubt, contact
Tarm Biomass.
The manual and supporting documentation must be retained by the owner/ system operator for
reference and future use.
The installer is responsible for familiarizing the owner/ system operator with all aspects of boiler op-
erations, safety procedures, monitoring and cleaning requirements, shut down procedures, and annual
maintenance requirements.
Introduction > Foreword

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 7
2.0 Product Description and Requirements for Safe Operation
2.1 Boiler Overview
2.1.1 Boiler Cut-away
Product Description and Requirements for Safe Operation > Boiler Overview
8
1
2
4
5
6
7
1. Control Panel
2. Loading Door
3. Fire Chamber
4. Primary Air Adjustment
5. Secondary Air Adjustment
6. Ash Door
7. Sight Glass
8. Gasification Tunnel
9. Secondary Air Injection
10. Heat Exchanger Tubes and Flue Gas Turbulators
11. Cleanout
12. Primary Air Injection
13. Flue Collar
14. Induced Draft Fan
15. Cleanout Cover
3
9
10
12
11
14
15
13
Fig 2.0

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 8
2.2 Boiler Function
2.2.1 General Operation
A generalized discussion of the operation of the Bonus Plus follows. Please refer to the cut-away
views of the boiler in Fig 2.0 and 2.1.
The Bonus Plus boiler is an induced draft wood gasification boiler designed to efficiently burn wood
as a component of a hydronic heating system.
The control panel (1) has the switch’s, gauge, and controls for the boiler’s operation.
Fuel is loaded through the load door (2) into the loading chamber (3) and the fire is kindled.
Air is controlled by the primary air control (4) and the secondary air control (5).
Secondary combustion takes place behind the ash door (6) and ashes are also removed through this
door.
Combustion can be monitored through the sight glass (7).
Chimney connector is attached to the flue collar (13).
The clean-out cover (15) is detachable and allows access for cleaning the heat exchanger pipes.
2.1.2 Boiler Control Panel
Product Description and Requirements for Safe Operation > Boiler Control Panel
C
E
B
F
A
D
G
I
H
Ps ºF
(A) Boiler pressure gauge
(B) Fuse, 6.3 Amp (behind the panel) Blows if overloaded. Contact an electrician if the fuse blows
frequently.
(C) Boiler temperature gauge.
(D) Overheat Thermostat 100 °C (212 °F)) manual reset after boiler drops below 75 °C (165 °F).
(E) Boiler circulator pump switch (not used in North America).
(F) Fan switch
Fig 2.1

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 9
The induced draft fan (16) pulls combustion air into the boiler via the primary and secondary air con-
trols and pulls gases from combustion through the heat exchanger and exhausts them out of the boiler.
The flue gas turbulators (10) provide for turbulent flow of the flue gas in the heat exchanger, increas-
ing heat transfer.
The heat exchanger tubes (10) transfers the heat from the combustion gasses to the boiler water.
The firebox (3) is the primary combustion chamber where the wood is loaded and the fire is started.
Secondary combustion air is injected in the nozzle just above the gasification tunnel (8) that serves to
hold combustion gasses in a high temperature, turbulent environment to achieve high efficiency com-
bustion.
The highly efficient wood combustion in the Bonus Plus boiler is achieved by the draft fan continu-
ously operating once wood in the boiler is ignited to achieve an efficient and clean burn of all the
wood loaded in the firebox. Due to the continuous heat output once the Bonus Plus is ignited the
boiler must be connected to a thermal storage system.
2.2.2 Description of Burn Process
A key component of the Bonus Plus boiler operation is the induced draft combustion fan. Both pri-
mary and secondary combustion air are both drawn into the boiler by the induction blower mounted on
the breach of the boiler. Primary and secondary combustion air are metered through air ducts into the
boiler with the precise volume necessary for proper combustion. The combustion air is drawn through
individually adjustable primary and secondary air valves. Primary air then is drawn into the firebox
where it is dispersed behind the firebox aprons into the primary combustion chamber just above
the top of the ceramic refractory combustion stones. Secondary air is drawn downward and then
back into the center combustion stone where it enters the combustion throat. Here secondary air is
turbulently mixed at high velocity with hot combustion gasses, which ignite and are burned very com-
pletely before being exposed to the heat exchange surfaces between the combustion chamber and the
breach. The correct proportions of air for combustion from the fan and gases from the wood are a pre-
requisite for optimal and environmentally friendly burning of the wood with the highest possible effi-
ciency.
A noteworthy construction feature is the special ceramic fuel tunnel (8) in the heart of the boiler
which ensures that the combustion temperature reaches more than 1800 °F (1000 °C). Combustion is
efficient, soot-free, and ensures optimal fuel use. The secondary combustion stones are essential to
achieving complete combustion with log wood. The stones allow the combination of exhaust gasses
and secondary air to reach very high temperatures while isolated from the quenching affect of the wa-
ter jacket.
Carefully engineered heat exchange tubes downstream from the combustion process are fitted with
removable turbulators to help ensure that a maximum amount of energy is transferred from the fuel
to the hot water jacket. The heat exchange tubes can be accessed for cleaning through the access
panel and door located at the top rear of the boiler Operation of the fan assumes that the boiler
can discharge its heat continually. The Bonus Plus must always be connected to a buffer tank of
adequate size (see page 53).
Product Description and Requirements for Safe Operation > Boiler Function

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 10
2.2.3 Safety Systems
The Bonus Plus comes with safety systems to prevent the following:
Pressure in the boiler exceeding 30 psi (2 bars) (over pressure)
Boiler water temperature exceeding 212 ºF (100 ºC)
To prevent an over-pressure condition, an ASME stamped pressure relief valve (provided) must be
installed on the boiler which opens at 30 psi to relieve the boiler pressure (See Section 3.5.1). Normal
pressure in the boiler should be 12-15 psi.
On the control panel there is an overheat thermostat. If the boiler exceeds (212 ºF) 100 ºC it will shut
off the fan to the boiler.
A gravity over-heat dump loop is also required. In the event of a power failure this loop should provide
dissipation for at least 10% of the boiler’s maximum rated output, assuming an ambient temperature of
65 ºF. in the area heated by the loop, and a mean water temperature of 180 ºF (82 ºC) (See Section
3.4.2).
2.2.4 Accessories
The boiler is shipped with loose and installing parts. See Section 3.3.2 for a complete listing of these
parts. Cleaning tools are provided with the boiler.
A barometric damper (draft stabilizer) is available for regulating chimney draft.
Plumbing around the boiler must include a three-port mixing valve in the orientation shown on instal-
lation drawing. The valve must be a Termovar Model 4440A-3, Lk810 or equivalent with a 72 ºC
element. Tarm Biomass provides this valve at an extra cost.
A flue thermometer (Part #339N) is highly recommended to help monitor the performance of the
Bonus Plus. This part is available from Tarm Biomass .
A Thermal Storage System is available from Tarm Biomass.
.
Product Description and Requirements for Safe Operation > Safety Systems

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 11
2.1.5 Boiler Fabrication and Testing
Your boiler was manufactured by HS Tarm , a world leader in hot water (hydronic) heating for over
80 years. The HS Tarm Bonus Plus Series boiler conforms to traditional high standards for quality
and reliability. It offers modern wood gasification technology with operating efficiencies at over 80%
when run properly. If treated properly and operated according to the guidelines in this manual it will
provide years of safe, dependable, and economical heating.
Bonus Plus boilers are designed and built in accordance with European Standard CEN 303-5. Safety
and performance testing and listing for U S markets have been performed by OMNI Test Laboratories,
Inc., Portland, Oregon. The boiler is tested and listed to applicable UL standards. The boiler is not
ASME stamped. The installer should follow local or state installation requirements.
The Bonus Plus wood gasification boiler is a log wood fired boiler designed and constructed for
highly efficient combustion of log wood. Do not burn other fuels in the Bonus Plus boiler. The Bonus
Plus is not a self contained weather-tight boiler. It should be installed within the heated building. Bo-
nus Plus log wood boilers must be installed with a thermal storage system capable of absorbing
the complete output of the boiler during periods when the building is not calling for heat.
2.1.6 Models and Applications
The Bonus Plus model 30 is available with an output of 102,000Btu/hr (30 kW). Specification data for
the Bonus Plus is provided in Section 6.3.
The boiler can be utilized as a single heat source, or in parallel with another boiler. Residential and
non-residential applications are appropriate.
2.3 Fuels
Chemically treated or painted wood is unsuitable as fuel. The Bonus Plus boiler is designed for burn-
ing of cord wood only. Any species may be used, however, the wood must be properly seasoned and
with a moisture content below 25%. Wood should be split into pieces with a diameter of four to six
inches and stacked in a well ventilated, covered, indoor or outdoor space for at least one full year. A
traditional, covered, outdoor wood stack can work well, but may require more drying time. A wood-
shed is ideal. We recommend the use of a wood moisture meter to test the core moisture content of
your wood. Wood briquettes or manufactured pure wood logs can also be used as fuel provided they
have a minimum cross section of 2.5 sq in. Manufactured logs should be at least 12” (0.25m) in
length. Excessively small and compact pieces of wood or wood pellets are not suitable. Coal cannot
be used as it becomes too compact and closes the combustion slot. The firebox can be filled to the
top.
Product Description and Requirements for Safe Operation > Boiler Fabrication and Testing

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 12
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
90
80
70
60
50
40
30
20
10
100
Moisture %
Btu/Lb
Product Description and Requirements for Safe Operation > Fuels
Fig 2.2
This chart shows how many Btu’s are lost by burning fuel with higher moisture content. We
recommend fuel with a moisture content of 20% or less.
The Bonus Plus is made to burn natural firewood. Both hardwood and softwood are suitable, but oak
should not be burned as the only source of wood for long periods because of its high acid content.
For effective gasification, the wood must be dry, i.e. moisture content 15-25%. In addition to increas-
ing the likelihood of generating creosote in the boiler, burning wet wood uses a substantial amount of
the wood energy to evaporate the water present in the wood, reducing the available energy for heat
(Fig 2.2).
The wood will dry out most quickly if it is cut into the appropriate length and split into pieces 4”-
6” (100-120mm) thick. The best length is 20” (0.5 m) for the Bonus Plus 30. The wood is best stored
in the open air under cover. Ideally the wood should be stored for at least one and a half years (two
summer seasons). Do not burn small pieces of wood or wood chips in the boiler as they can block the
combustion slot. Also, it can be difficult to control the combustion process effectively with small
wood pieces and chips.
WARNING
If a fan is used in the fuel storage area, it should be installed so as not to create negative
pressures in the room where the solid-fuel burning appliance is located.

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 13
2.4 Building Requirements
 The boiler must be connected to a tile-lined masonry chimney or to a factory-built Type UL
103 HT approved chimney in good condition. See the details in Section 3.2
 A dedicated supply of fresh combustion air provided near the boiler is recommended for effi-
cient, safe operation. This supply must not be directly connected to the boiler.
 Installation on a non-combustible floor only.
 A dedicated 120 VAC power supply is required (See Section 3.4.9).
 Revision of existing heating system piping may be appropriate to properly utilize the equip-
ment. Although Tarm Biomass can provide advice and design detail on the integration of this
boiler with the heating system of the building, the ultimate responsibility for the performance
of the system rests with the installer.
 Please observe the guidelines and the various national and local regulations.
 Bonus Plus boilers are designed and approved as heaters for hot water systems with permissi-
ble outflow temperatures of up to 203 ºF (95 ºC).
2.5 Owner Responsibilities
Successful operation of this boiler will require daily involvement by the owner/system operator.
Biomass boilers operate differently from fossil fuel boilers, requiring more oversight and a diligent
cleaning regimen.
 The owner/system operator is responsible for correct operation of the boiler per guidelines in
Sections 4.0 and 5.0 of this manual.
 Incorrect operation can reduce the boiler life.
Product Description and Requirements for Safe Operation > Building Requirements
WARNING
Risk of Fire!
 Do not operate with flue draft exceeding –.10 (-2.54mm) water column.
 Do not operate with fuel loading or ash removal doors open.
 Do not store fuel or other combustible material within marked installation clear-
ances.
 Inspect and clean flues and chimney regularly.
 Do not use chemicals to start unit firing.
CAUTION
Hot Surfaces!
 Keep children away.
 Do not touch during operation.
 Maximum draft marked on nameplate.
☼
DANGER
Risk of Fire or Explosion!
Do not burn garbage, gasoline, gasoline type lantern fuel, kerosene, charcoal lighter fluid,
drain oil, or other flammable liquids to start or “freshen up” a fire in the boiler.

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 14
3.0 Boiler Installation & Start-up
This section is directed at the installer.
3.1 Planning
3.1.1 Sizing the Boiler
It is critical to size the boiler properly. A proper, up to date heat load calculation is advised. An accu-
rate history of building fuel usage over several years can help to calculate the proper size boiler.
Boiler sizing is the responsibility of the installer. Tarm Biomass bears no responsibility for boiler
sizing, but can provide sizing input.
3.1.2 Choosing an Installer
Choosing a competent, licensed installer is critical to the successful installation of the boiler. The
installer is responsible for all planning, installation, start-up, troubleshooting, owner training, and an-
nual maintenance for the boiler. Some aspects of the system piping, start-up, and operation may differ
from normal practice in fossil fuel boiler installation. To be successful, the installer must study this
manual, understand the installation tasks, and contact Tarm Biomass for help when necessary.
3.1.3 Locating the Boiler and Boiler Clearances
The boiler must be installed with the minimum installation clearances to combustible materials out-
lined on the next page. Clearances may only be reduced by means approved by the regulatory authori-
ties.
 The boiler is not suitable for outdoor installation. It must be located in a conditioned space.
 The boiler must be placed on a level, non-combustible floor, such as a concrete slab on earth.
If you have the boiler 8” above the floor it makes it easier to load and clean the boiler.
 If the boiler is placed near inhabited rooms, so that flue gas can easily penetrate into these
rooms, a carbon monoxide alarm must be installed that can give a warning regarding possible
escapes of carbon monoxide into the inhabited rooms.
Boiler Installation & Start-up > Planning
CAUTION
Safety faults or deficiencies with the boiler or installation must be rectified as quickly
as possible. Either by the owner/system operator or the installer.
☼
All cover plates, enclosure, and guards must be maintained in place at all times, except
during maintenance and servicing.
☼
CAUTION

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 15
The boiler must be installed with the minimum installation clearances to combustible materials out-
lined below. Clearances may only be reduced by means approved by the regulatory authorities.
Recommended Distances in the Boiler Room Units Bonus Plus 30
A-Minimum Clearance for Blower Maintenance Inches 21
B-Minimum Clearance to Combustibles Inches 12
C-Minimum Distance for Cleaning and Maintenance Tasks Inches 21
D-Minimum Clearance to Combustibles Inches 36
E-Minimum Clearance to Combustibles Inches 24
F-Minimum Distance for Combustibles to Pipe Inches 18
G-Maximum Distance for Flue Pipe Feet 0-4
H-Ideal Location for Draft Regulator (Barometric Damper) - -
Boiler Installation & Start-up > Planning
CAUTION
DO NOT INSTALL THIS BOILER IN A MOBILE HOME. There is no safe way this boiler
can be installed inside a mobile home.
☼

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 16
3.1.4 Plumbing and Mechanical
The boiler must be connected to a suitable chimney. Chimney requirements are discussed in Section 3.2.
A dedicated supply of fresh combustion air should be provided near the boiler for efficient and safe
operation, but must not be directly connected to the boiler. Outside combustion air is especially impor-
tant for the Bonus Plus due to its powerful induction blower (See Section 3.2.1).
For the heating system piping, it is possible to use either copper or iron piping materials. The supply
and return pipe should be insulated to avoid heat loss. Included in Section 6.5 are conceptual piping
diagrams showing the correct layout for a variety of situations. Tarm Biomass can provide additional
conceptual plumbing diagrams
A permanent pressurized domestic water supply must be provided with proper automatic filling and
pressure reduction valves.
Use of a suitable antifreeze mix is allowed, but will cause a loss in heat transfer efficiency.
If water quality is poor, water treatment additives should be considered. Boiler system water pH
should be 8.0-8.6.
A thermostatic mixing valve or loading unit (not provided), set to open at 140-160 ºF (60-72 ºC), is
required to temper return water to prevent cold return water from reaching the boiler. This helps pre-
vent boiler corrosion. Tarm Biomass can provide this valve or loading unit for an additional cost.
A circulator (Size and brand to be determined by the installer (not provided)) should be installed as
C3 per drawings suggested by Tarm Biomass.
An aquastat (Honeywell L4008B (provided)) must be installed to protect the boiler from over-
temperature conditions by energizing a chosen heating zone.
An aquastat (Honeywell L6006A (provided)) must be installed to protect the boiler from over-
temperature conditions by energizing the C3 boiler circulator.
A tankless hot water coil is not available for the Bonus Plus.
Tarm Biomass recommends the use of the BLTCONTROL (available through Tarm Biomass) when
burning the Bonus Plus in conjunction with a back up boiler. The BLTCONTROL is a three position
control that allows switching between wood only, wood with automatic back up, or back up only, by
controlling the operation of the back up auxiliary boiler. BLTCONTROL takes input from a zone
relay control and determines, based on the thermal storage system temperature, whether to pull heat
from the thermal storage system or the back up auxiliary boiler. The BLTCONTROL easily inte-
grates the Bonus Plus boiler and thermal storage system with an existing fossil fuel heating system.
CAUTION
Any plastic or rubber tubing used with a Tarm Biomass boiler must have an oxygen barrier, or
boiler corrosion will occur. If radiant tubing without an oxygen barrier is installed, water in the
tubing part of the heating system must be separated from the boiler. Separation of system com-
ponents is typically done by using a heat exchanger. Use of radiant tubing without an oxygen
barrier will void the boiler warranty.
☼
Boiler Installation & Start-up > Planning

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 17
3.1.5 Electrical
For the Bonus Plus boiler a 120 VAC, 60 hertz, 3-wire power supply is required. This electrical
connection should be from a dedicated 15 amp circuit breaker. A master service switch for the boiler,
mounted on the boiler or on the wall in the proximity of the boiler, is recommended (see Section
6.4.2). Locally enforced electrical codes must be followed.
3.2 Preparing the Chimney
The chimney is one of the most critical factors in the successful operation of any solid fuel heater, in-
cluding the Bonus Plus boiler. A good chimney will provide a continuous and dependable draft to pull
the exhaust gasses out of the building.
Follow manufacturer’s installation instructions for installing and supporting any specific chimney
product.
Flue gas exhaust temperatures can be low enough to cause condensation in chimneys. Condensation
will, over time, damage a masonry chimney. Accordingly, installation of a stainless steel chimney
liner (made with 304, 316, or 321 alloys) inside the chimney flue is strongly recommended.
At the connection to a factory-built chimney, a dripless adaptor must be used.
The chimney draft must be stable and between -0.025” (-0.6 mm) and -0.05” (-1.25 mm) water col-
umn.
The top of chimney must be 3 feet (0.9 m) above the roof and 2 feet (0.6 m) above any structure
within 10 feet (3.0 m) measured horizontally.
For the Bonus Plus 30 best draft will be provided by a chimney which has an 6” (152mm) ID round
flue, is 20-30 feet (6.0-9.0m) in height and which is located inside the heated structure. The chimney
must be capable of maintaining a breech draft of -0.05” (-1.25mm) WC during normal boiler opera-
tion.
Your Bonus Plus gasification boiler is designed to burn efficiently and with virtually clear emissions,
but under certain conditions creosote deposits can form in your chimney. Chimneys that are too large,
are poorly insulated, or have bends in the flue passages are especially prone to problems with draft
and/or creosote.
Boiler Installation & Start-up > Preparing the Chimney
NOTE
The boiler must be connected to a tile-lined masonry chimney or to a Factory-Built Type UL
103 HT approved chimney. The chimney must be in good condition. If the boiler is connected to
a dirty or inadequate chimney, it can present a serious fire hazard. All chimneys and connec-
tions must conform to NFPA standard #211. No other appliance should be connected to this
flue unless allowed by the local code authority. Consult your local inspector for chimney re-
quirements and install the boiler in accordance with all applicable codes. Please review the fol-
lowing diagram before connecting the boiler to the chimney.
WARNING
If the draft exceeds the recommended maximum, it could cause a solid fuel fire to burn out
of control.

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 18
Fig 3.1
The smoke pipe connecting the boiler to the chimney flue must be black or stainless, have a minimum
thickness of 24 gauge, and rise a minimum of ¼” per foot of run toward the chimney (Fig3.1). Smoke
pipe sections must be attached to one another with a minimum of three sheet metal screws and sealed
with high-temp silicone. The smoke pipe should not contain more than two 90º elbows (45º elbows
are preferred over 90º elbows ).
MASONRY CHIMNEYS: Masonry chimneys must be lined, either with code-approved masonry or
pre-cast refractory tiles, stainless steel pipe, or poured in place liner. Do not use an unlined chimney
FACTORY BUILT CHIMNEYS: Factory built chimneys must be tested and listed for use with solid-
fuel burning appliances to the High Temperature (HT) Standard (2100 ˚F(1148 ˚C )), UL 103, for the
United States. Factory-Built chimneys must be installed as per the manufacturers instructions.
Strong winds blowing across the top of a chimney or a chimney which has a particularly strong natural
draft can cause the Bonus Plus boiler to continue burning (heating) when the draft fan is off. This is
an unlikely scenario, as the blower on a Bonus Plus, used with a thermal storage system, should rarely
be off while a fire is present. If however, an irregular or excessively high draft presents problems, the
solution is the use of a barometric draft regulator or the use of a proper chimney cap that helps in the
prevention of down drafts.
Installation requirements for a barometric damper (draft regulator).
 The diameter of the draft regulator must be equal or greater than that of the chimney connector.
 The draft regulator should be installed as close as possible to the boiler, on the chimney con-
nection or on chimney itself.
 The draft regulator adjustment should be made with a vacuum gauge, if possible, with the
boiler operating at full output. If the start-up is made in warm weather, a readjustment may be
necessary in cold weather.
 If, at the maximum adjustment (maximum opening of the shutter of the draft stabilizer), the
draft is always higher than -0.05” (1.25 mm) of water column, a second draft regulator may be
required.
 Recommended draft regulator location (1) is shown in Fig 3.1.
Boiler Installation & Start-up > Preparing the Chimney

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 19
3.2.1 Outside Combustion Air
Provision for outside combustion air may be necessary to ensure that fuel-burning appliances do not
discharge products of combustion into the house. Guidelines to determine the need for additional
combustion air may not be adequate for every situation. If in doubt, it is advisable to provide addi-
tional air. The Bonus Plus, due to its powerful induction fan, needs adequate air to make up for the air
being pushed up the chimney especially during start up before the chimney is warm.
Outside air may be required if:
1. The solid fuel fired appliance does not draw steadily; experiences smoke roll out from the
loading door, burns poorly, or back-drafts whether or not there is combustion present.
2. Existing solid fuel fired equipment in the house, such as fireplaces or other heating appliances
smell, do not operate properly, suffer smoke roll out when opened, or back-draft whether or
not there is any combustion present.
3. Any of the above symptoms are alleviated by opening a window slightly on a calm (windless
day.
4. The house is built very tightly with a well sealed vapor barrier or foam type insulation and
tight fitting windows and/or has any powered devices which exhaust in the house.
5. There is excessive condensation on windows in the winter.
6. A non-balancing ventilation system is installed in the house.
7. Where fans are used in the fuel storage area, they should be installed so as not to create nega-
tive pressures in the room where the boiler is located.
If these, or other indications, suggest that infiltration air is inadequate, additional combustion air
should be provided from the outdoors.
Bonus Plus boilers are not suitable for direct connection to outside air. Outside air should be ducted to
no closer than 12” (305mm) from the boiler. A 6” (152mm) duct should be large enough for all sizes
unless the duct run is over 25 feet (7.6m).
If a mechanical ventilation system (air exchange or heat recovery) is already present in the home it
may be able to provide sufficient combustion make-up air for the solid fuel fired appliance. The venti-
lation system may need to be re-balanced after installation of the Bonus Plus.
3.3 Setting the Boiler
3.3.1 Receiving the Boiler
Boilers are shipped on a single skid. Loose materials are consolidated into boxes strapped to the skid
or placed inside the combustion area of the boiler. Please unpack the boxes and verify that all items
have been received. Make certain that any damage or shortage is noted to the shipping receiver.
To move the unit into the boiler room the lift ring on the top of the boiler can be used.
To move the boiler around the inside of the boiler room rollers can be used under the boiler.
Boiler Installation & Start-up > Preparing the Chimney

Bonus Plus Instructions Tarm Biomass 1-800-782-9927 Version 11/14 Page 20
3.3.2 Temporary Storage
If the boiler installation is going to take place at a later date the boiler and components need to be
stored in a safe, dust-free, dry location. Moisture can damage the insulation, electrical components,
and ceramics. If boiler is subjected to this kind of environment, it could void the warranty.
3.3.3 Moving the Boiler
See Section 6.3 Specification Data for weights and measurements of the Bonus Plus boiler. The
boiler is heavy and large! Moving the boiler into place requires planning and resources. The boiler
may be unloaded using a pallet jack or forklift. Alternately, it can be lifted from above by utilizing the
lifting rings welded to the top of the boiler.
3.3.4 Boiler Set-up
After the packaging is removed and the boiler is set into place, it should be checked to assure that it is
level and securely placed. Loose parts and accessories shipped with the boiler should be removed and
stored in a safe place. A copy of this manual is shipped with the boiler for reference during installa-
tion. The boiler can be set using leveling bolts located on each corner.
It is not necessary to remove the wooden shipping braces and wedges located within the boiler. They
will burn away within a few hours of initial firing.
3.4 Connections to the Boiler
The following connections must be made to the boiler, in order for it to function:
 The boiler flue gas exhaust collar must be connected to the chimney system.
 The heating system piping must be connected to the boiler supply and return connections.
 Electrical power must be provided at the boiler electrical terminal box.
3.4.1 Chimney Connection
The connection between the boiler and the chimney system should be single wall 24 gauge (minimum)
stainless or black pipe, unless prohibited by the local code authority.
 The single wall chimney connector must not pass through an attic, roof space, closet or similar
concealed space, or a floor, or ceiling.
 Where passage through a wall or partition of combustible construction is desired, the installa-
tion must conform to NFPA 211.
 The chimney connection pipe must be placed over the outside of the boiler’s flue gas exhaust
pipe. A flue collar adaptor is available from Tarm Biomass.
Boiler Installation & Start-up > Setting the Boiler
CAUTION
CAUTION
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Do not install a flue damper in the exhaust venting system of this unit.
Do not connect this unit to a chimney flue serving another heating appliance, unless approved by
the local code authority.
Do not connect the boiler to any air distribution duct or system.
Install vent at clearances specified by the vent manufacturer.