Viessmann KOB Pyrot KRT Series, KOB Pyrot KRT150, KOB Pyrot KRT220, KOB Pyrot KRT300, KOB Pyrot KRT400 Technical Data Manual

...
Technical Data Manual
for use by engineers and heating contractors
Pyrot
Wood-fired Boiler
KRT 150 to KRT 540 Series
r
Product may not be exactly as shown
Pyrot with its patented rotating combustion chamber design, features the industry’s most advanced combustion technology. A feed auger continuously moves the wood fuel onto a moving grate where gasification takes place. The combustible gases blend with precisely controlled secondary air, resulting in a complete combustion with ultra low emissions. Max. output: 150 to 540 kW (512 to 1843 MBH) Min. output: 45 to 140 kW (154 to 478 MBH)
5443 109 v1.9 05/2013
Product Information
Pyrot
Pyrot 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 rotating combustion wood-fired boiler
5 models from 512 to 1843 MBH
For dry wood fuels with max. water content of 35%
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.
Automatic ignition device limits idling and saves fuel.
Low maintenance with fully-automatic de-ashing, optional pneumatic cleaning system and flue gas de-duster.
Advanced safety equipment ensures safe and reliable operation.
Custom design of your system by our team of experts.
Available as convenient portable boiler enclosure.
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.
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5443 109 v1.9
Pyrot Technical Data
Boiler Description
Boiler Description
General Information
Description
The PYROT Rotating Combustion 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. W35-40, see section “Wood Fuel Requirements”. The PYROT Rotating Combustion System is characterized by high efficiencies and perfect combustion at all load levels. The PYROT 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 in-feed auger conveys the wood fuel diagonally from below into the fire box. The holding devices for the back-burn sensor and the thermal extinguishing valve are situated on the in-feed auger. Above the in­ feed auger, there is a metering container with a light barrier to ascertain the level of the fuel insulating layer required.
- The wood fuel is ignited automatically by an electric heat gun, at the time of the boiler start. The gasification of the fuel is carried out on a feed grate moved by a worm-geared motor. The ash falls in an ash bin below. An automatic de-ashing system is optional. The fire box is heavily insulated and lined with fire clay refractory elements.
- The combustion gases rising from the fire box are swept up by the rotating secondary airflow brought to bear from the rotation blower and burned out completely in the round combustion chamber. The thermal energy from the combustion gases is transmitted to the boiler water in horizontal heat exchanger tubes. The combustion chamber is heavily insulated and provided with excellent access through the boiler door in the front.
- A flue gas re-circulation system reduces the temperature in the fire box while maintaining the highest possible degree of efficiency. This increases the service life of the un-cooled refractory elements in the gasification zone. With the basic setting, the ratio of re-circulated gas to fresh air is precisely adjusted according to the amount of wood fuel that is burned. A mechanical adjustable damper provides a constant ratio of the quantity of re-circulated gas to fresh air over the entire output range.
- The flue gas blower is specially designed for wood heating operation and is very quiet. The motor has a solid, heat resistant design with a heat dissipation hub and is spring supported. The blower casing has a round intake port and a round blowout nozzle. Installation is possible on the top, side or rear of the flue gas collector within 360° rotation.
Supplied with:
- Boiler with rotating combustion chamber and tube heat exchanger including supply and return temperature sensors
- Fire box with moving grate and light barriers for ember monitoring
- Automatic ignition blower
- 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
- Set of displacement rods
- Flue gas re-circulation system
- Flue gas blower including flue gas temperature sensor and oxygen sensor
- Draft damper for installation in the flue gas pipe
- 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
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
Accessories for PYROT Rotating Combustion System:
- Flue gas de-duster 24 USG (90 L)
- Metal mesh filter
- Automatic de-ashing system in bin, 63 USG (240 L)
- Automatic de-ashing in bin, 211 USG (800 L)
- Automatic de-ashing in base container
- Pneumatic cleaning system
- Operating pressure 30 or 60 psi
- Two-stage in-feed auger
- Insulation for flue gas re-circulation line
- Thermal safety flush valve
- Slide valve / Rotary valve
- Boiler pump and boiler mixing valve
- Ecotronic control system options:
- 3 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
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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
A number of lifting lugs will be provided on each boiler and tube heat exchanger where lifting gear may be attached. A tie bar is required to lift the boiler by the boiler supply and boiler return flanges.
Minimum clearances to walls for installation and maintenance work must be observed. Anti-vibration boiler supports may be used if anti-vibration measures are required.
Pyrot 150 - 300:
Hoist by the lifting lug.
Pyrot 400 - 540:
Hoist by boiler supply and boiler return flanges using a lifting lug.
Pyrot Technical Data
WARNING
Follow instructions for proper installation. For wood-fired installations: This wood-fired boiler must be installed in accordance with local codes if any; if not, follow B 365-01, Installation Code for Solid-Fuel Burning Appliances and Equipment.
A Lifting lugs
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5443 109 v1.9
Pyrot Technical Data
Delivery Condition
Standard delivery condition
The standard delivery condition of the Pyrot 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:
- The combustion chamber is mounted to the fire box
- Boiler is fully bricked
- Boiler door is mounted to the combustion chamber including secondary air rotary blower
- Primary air vents are attached to the fire box
- Flue gas collector is attached to the tube heat exchanger
- Pneumatic cleaning system (optional) is attached to the flue gas collector
General Information
Components that are not attached or installed to the boiler at time of delivery (scope of the contractor):
- Electrical components which include temperature sensors, oxygen sensor, light barriers for the fire box, ignition blower, low water cut off, safety temperature limiter, 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
- Re-circulation system and insulation (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 KRT150 KRT220 KRT300 KRT400 KRT540
Minimum size door
Minimum ceiling opening (W x H)
Minimum ceiling opening including pneumatic cleaning system
47a in. x 78c in. (1200 mm x 2000 mm)
47a in. x 112a in. (1200 mm x 2850 mm)
47a in. x 128 in. (1200 mm x 3250 mm)
59 in. x 88b in. (1500 mm x 2250 mm)
59 in. x 112a in. (1500 mm x 2850 mm)
59 in. x 128 in. (1500 mm x 3250 mm)
59 in. x 88b in. (1500 mm x 2250 mm)
59 in. x 126 in. (1500 mm x 3200 mm)
59 in. x 141c in. (1500 mm x 3600 mm)
70c in. x 98b in. (1800 mm x 2500 mm)
70c in. x 130 in. (1800 mm x 3300 mm)
70c in. x 145c in. (1800 mm x 3700 mm)
70c in. x 98b in. (1800 mm x 2500 mm)
70c in. x 137c in. (1800 mm x 3500 mm)
70c in. x 153b in. (1800 mm x 3900 mm)
5443 109 v1.9
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General Information
Pyrot Technical Data
Delivery Condition (continued)
Special delivery condition (partially disbanded)
For special circumstances like restricted space to bring the boiler into the heating room, the size of the boiler can be reduced by detaching additional components to the ones as described in section “Standard delivery condition”. The assembly of these components require additional assembly time of approximately 6 hours.
Measurements of the largest part for reduced boiler size
Boiler model KRT150 KRT220 KRT300 KRT400 KRT540
Minimum size door
Minimum ceiling opening (W x H)
Special delivery condition (fully disbanded)
For special circumstances like heavily restricted space to bring the boiler into the heating room, the size of the boiler can be reduced by detaching additional components to the ones as described in section “Standard delivery condition” and “Special delivery condition partially disbanded”. The assembly of these components require welding and additional assembly time of approximately 20 hours.
35b in. x 49a in. (900 mm x 1250 mm)
39a in. x 102a in. (1000 mm x 2600 mm)
46 in. x 61 in. (1170 mm x 1550 mm)
49a in. x 103a in. (1250 mm x 2620 mm)
The following additional objects will be delivered disbanded:
- The combustion chamber and the fire box are separate
- No brickwork inside the combustion chamber and fire box
- No insulation and panels are attached to the combustion chamber
46 in. x 61 in. (1170 mm x 1550 mm)
49a in. x 118 in. (1250 mm x 3000 mm)
The following additional objects will be delivered disbanded:
- The tube heat exchanger is a separate piece
- The flue gas collector is detached from the tube heat exchanger
- The boiler door is detached from the tube heat exchanger (welding required)
55 in. x 67 in. (1400 mm x 1700 mm)
59 in. x 122 in. (1500 mm x 3100 mm)
55 in. x 67 in. (1400 mm x 1700 mm)
59 in. x 130 in. (1500 mm x 3300 mm)
Measurements of the largest part for reduced boiler size
Boiler model KRT150 KRT220 KRT300 KRT400 KRT540
Minimum size door
Minimum ceiling opening (W x H)
35b in. x 49a in. (900 mm x 1250 mm)
39a in. x 85 in. (1000 mm x 2160 mm)
46 in. x 59 in. (1170 mm x 1500 mm)
49a in. x 85c in. (1250 mm x 2180 mm)
46 in. x 59 in. (1170 mm x 1500 mm)
49a in. x 98c in. (1250 mm x 2510 mm)
55 in. x 67 in. (1400 mm x 1700 mm)
59 in. x 96b in. (1500 mm x 2450 mm)
55 in. x 67 in. (1400 mm x 1700 mm)
59 in. x 110 in. (1500 mm x 2800 mm)
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5443 109 v1.9
Pyrot Technical Data
Wood Fuel Requirements
General Information
The PYROT 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.
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)
- 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.
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)
Max. length in. (cm)
Coarse sieve nominal mesh width in. (mm) 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 in² (500 mm²) up to a length of max. 6a in. (160 mm) can be tolerated.
Fine sieve nominal mesh width in. (mm)
Size of briquettes:
- Fraction of one-offs. max. 5% with cross-section of max. c in2 (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).
Consequence 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 109 v1.9
7
General Information
Wood Fuel Requirements (continued)
Pyrot Technical Data
Maximum water content
The maximum allowable water content of the fuel for Pyrot systems is limited to 35%. The water content impacts the maximum boiler output.
Non-wood fuels
Non-wood fuels, even if consisting of biomass, such as needles, foliage, grain, straw, fruit pits, etc., are unsuited as fuel for boiler operation and may not be used.
Limitation super fines & 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.
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)
W10 to W20 C1 Sawdust, untreated (planing shop)
Suitable fuel types for Pyrot 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 Pyrot systems allow for a max. of 35% water content (W).
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]
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
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
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)
Note: For size of wood chips, see page 7.
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5443 109 v1.9
Pyrot Technical Data
General Information
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).
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Safety
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
Pyrot Technical Data
The PYROT Rotating Combustion 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 PYROT rotating combustion system is output­controlled 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.
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5443 109 v1.9
Pyrot Technical Data
Mechanical Room
Safety
Ensure the mechanical room complies with the requirements in these instructions.
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 PYROT rotating combustion 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.
Foundation dimensions
Boiler model KRT- 150 220 300 400 540
a in. (mm) 6113/
b in. (mm)
c in. (mm)
d in. (mm) 1123/
e in. (mm)
f in. (mm)
g in. (mm)
h in. (mm) 97/8 (250) 97/8 (250) 97/8 (250) 97/8 (250) 97/8 (250)
5443 109 v1.9
x Fuel feed to the boiler y Heat-resistant floor Surface medium grey Boiler supporting surface
(1570) 8011/
1 6
(2050) 8011/
1 6
(2050 967/8 (2460) 967/8 (2460)
1 6
34a (870) 45a (1150) 45a (1150) 54c (1390) 54c (1390)
24e (620) 26c (680) 26c (680) 31b (800) 31b (800)
(2850)
1 6
123a (3130) 142a (3613) 147d (3738) 161b (4103)
20b (520) 20b (520) 28b (723) 17f (448) 21e (543)
29d (740) 29d (740) 34f (880)
(960) 4311/
1 6
(1095)
1 6
3713/
34a (870) 45a (1150) 45a (1150) 54c (1390) 54c (1390)
11
Safety
Combustion Air Supply
Pyrot Technical Data
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.
12
Confined spaces
When a furnace or boiler is enclosed in a space that has a volume less than 20% of that to be heated by the appliance, the space shall:
a) have a permanent opening or openings for natural air circulation with a minimum net free area of 1.5 in² / 1000 Btu/h (3300 mm² / kW) input, and
b) connect to another space or spaces such that the total volume of air available for natural air circulation is at least 30% of the total volume to be heated by the appliance.
The minimum dimension of any opening specified in item (a) shall be no less than 1 in. (25 mm) The lower edge of at least one opening shall be located within 1.5 ft. (0.5 m) of the floor of the enclosed space, and the upper edge of at least one opening shall be located within 1.5 ft. (0.5 m) of the ceiling of the enclosed space.
Note: The intent of this Clause is to allow either one long vertical opening or two shorter horizontal openings, one high and the other low, to allow for air circulation to prevent overheating of the appliance.
Unconfined spaces
Where the boiler is located in an unconfined space in a building having insufficient infiltration, additional air for combustion and ventilation shall be obtained from outdoors or from spaces freely communicating with the outdoors. Under these conditions, permanent opening(s) shall be provided so that the total air received through these openings will be at least as much as would be admitted by openings having a total free area of 1 in² / 5,000 Btu/h or (450 mm² / kWh) of the total input rating of all wood-fired appliances.
Louvers and grilles
In calculating free area as specified, consideration shall be given to the blocking effect of louvers, grilles, or screens that protect openings. Screens shall be no smaller than ¼ in. (6 mm) mesh and shall be readily accessible for cleaning. If the free area through a design of louver or grilles is known, it shall be used in calculating the size of opening required to provide the free area specified. If the design and free area are not known, it shall be assumed that wood louvers have 20 - 25% free area and metal louvers and grilles have 60 - 75% free area.
5443 109 v1.9
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