GWH 345/450 ESR
Temperature Modulated with Electronic Ignition
Suitable for heating and recirculating potable water
GWH-345/450-ESR-N - Natural Gas
GWH-345/450-ESR-L - Liquefied Petroleum (LP) Gas
6 720 607 909 US (2008.02) JS
Warning: If the information in this manual is not followed exactly, a fire or explosion may result causing property damage, personal injury or death. Do not store or use gasoline or other flammable vapor and liquids in the vicinity of this or any other appliance.
Improper installation, adjustment, alteration, service or maintenance can cause injury or property damage. Refer to this manual. For assistance or additional information consult a qualified installer, service agency or the gas supplier.
In the Commonwealth of Massachusetts this product must be installed by a licensed plumber or gas fitter.
Upon completion of the installation, these instructions should be handed to the user of the appliance for future reference.
What to do if you smell gas
•Close gas valve. Open windows and doors, and evacuate the building.
•Do not try to operate any appliance.
•Do not touch any electrical switch; do not use any phone in your building
•Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
•If you cannot reach your gas supplier, call the fire department.
•Installation and service must be performed by a qualified installer, service agency or the gas supplier.
Index
Index
1 |
Warning |
2 |
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2 |
Appliance details |
4 |
2.1 |
Features |
4 |
2.2 |
GWH-345/450-ESR Specifications (Technical data) |
4 |
2.3 |
Unpacking the GWH-345/450-ESR heater |
5 |
2.4 |
General rules to follow for safe operation |
6 |
2.5 |
Dimensions and minimum installation clearances |
7 |
2.6 |
Applications |
8 |
2.7 |
Water quality |
9 |
3 |
Installation instructions |
10 |
3.1 |
Introduction |
10 |
3.2 |
Proper location for installing your heater |
10 |
3.3 |
Heater placement and clearances |
10 |
3.4 |
Mounting installation |
10 |
3.5 |
Combustion air requirements |
11 |
3.6 |
Venting |
13 |
3.6.1 |
Vent material and specifications |
13 |
3.6.2 |
Vent connections and air inlet restrictors |
14 |
3.6.3 |
Condensate drain requirements |
17 |
3.6.4 |
Room sealed installation (Twin pipe) |
17 |
3.6.5 |
Vertical terminations |
18 |
3.6.6 |
Horizontal terminations |
18 |
3.6.7 |
Exhaust vent configuration examples |
21 |
3.7 |
Gas piping & connections |
22 |
3.8 |
Measuring gas pressure |
24 |
3.9Checking restrictor plate size by measuring CO2 level value 24
3.10 |
Water connections |
25 |
3.11 |
Electrical connections |
25 |
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4 |
Operating instructions |
27 |
4.1 |
Initial filling instructions |
27 |
4.2 |
For your safety read before operating your water heater |
27 |
4.3 |
Startup instructions |
27 |
4.4 |
Power |
28 |
4.5 |
Recirculating water temperature |
28 |
4.6 |
Temperature and hot water flow |
28 |
4.7 |
Freeze protection |
28 |
4.8 |
Electrical diagram |
29 |
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5 |
Maintenance and service |
30 |
5.1 |
Service mode |
30 |
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6 |
Troubleshooting |
32 |
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7 |
GWH-345/450-ESR Functional scheme |
34 |
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8 |
Interior components diagram and parts list |
35 |
8.1 |
Interior components |
35 |
8.2 |
Components diagram |
36 |
8.3 |
Parts list |
37 |
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9 |
Protecting the environment |
38 |
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10 |
Ten Year Limited Warranty |
39 |
1Warning
For your safety
Do not store or use gasoline or other flammable, combustible or corrosive vapors and liquids in the vicinity of this or any other appliance.
Warning: Carefully plan where you install the heater. Correct combustion air supply and flue pipe installation are very important. If a gas appliance is not installed correctly, fatal accidents can result from lack of air, carbon monoxide poisoning or fire.
Warning: Exhaust gas must be vented to outside using 3" single wall sealed stainless steel vent pipe suitable for category III vent systems and temperatures up to 480°F. Vent and combustion air connector piping must be sealed gas-tight to prevent possibility of flue gas spillage, carbon monoxide emissions and risk of fire, resulting in severe personal injury or death.
Warning: Place the recirculating water heater in a location where water leaks will do NOT DAMAGE adjacent areas or lower floors.
Warning: Field wiring connections and electrical grounding must comply with local codes, or in the absence of local codes, with the latest edition of the National Electric Code, ANSI/NFPA 70, or in Canada, all electrical wiring must comply with the local codes and the Canadian Electrical Code, CSA C22.1 Part 1.
Warning: Shock hazard line voltage is present. Before servicing the recirculating water heater, turn off the electrical power to the recirculating water heater at the main disconnect or circuit breaker. Failure to do so could result in severe personal injury or death.
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Warning
Warning: The recirculating water heater must be disconnected from the gas supply piping system during any pressure testing of that system at test pressures equal to or more than 0.5 psig (14” W.C.).
FCC:
This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.
Caution: Any changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.
Fig. 1
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3 |
Appliance details
2Appliance details
2.1Features
Parts
• Sealed combustion burner.
Safety
•Ionization flame sensor
•Over temperature protection.
High quality materials for long working life
•Copper heat exchanger
•Compact space saver: mounts on a wall with supplied bracket.
Features
•LCD screen to display temperatures, burner operation and error codes
•On/Off button and separate temperature controls for domestic water heating and recirculating water
•Reset button
•Failure codes for diagnostics and repair
•Freeze prevention cycle.
BOSCH is constantly improving its
iproducts, therefore specifications are subject to change without prior notice.
2.2GWH-345/450-ESR Specifications (Technical data)
Approved in US/Canada
Capacity
GWH345 Maximum flow rate: 3.5 GPM (13 l/min) at a 45°F (25°C) rise.
GWH450 Maximum flow rate: 4.5 GPM (17 l/min) at a 45°F (25°C) rise.
Maximum output
GWH345 - 77,900 Btu/h (22.8 kW)
GWH450 - 98,400 Btu/h (28.8 kW)
Maximum input
GWH345 - 95,000 Btu/h (27.8 kW)
GWH450 - 120,000 Btu/h (35.1 kW)
Efficiency in %
GWH345 Combustion efficiency: 82%
GWH450 Combustion efficiency: 81%
Min. Output
GWH345 - 23,900 Btu/h (7 kW)
GWH450 - 35,500 Btu/h (10.4 kW)
Temperature Control
Selection range: 115°F (45°C) - 190°F (90°C)
Gas Requirement
Gas connection (inches) - ¾”
Inlet gas pressure under operation (with a high hot water flow rate)*
•Propane: 11” - 14” water column
•Natural Gas: 5.5” - 8” water column.
* To measure gas pressure, see Measuring Gas Pressure, chapter 3.8.
Venting
3" AL 29-4C single wall sealed stainless steel vent pipe.
See chapter 3.6 for Venting.
Water
•Hot water connection - ¾” NPT
•Cold water connection - ¾” NPT.
Combustion
•NOx ≤ 100 ppm
•CO ≤ 250 ppm
•CO2 level (see table 8 for correct restrictor dimension).
Dimensions
•Depth (in): 11 ¾” (300 mm)
•Width (in): 15 ¾” (400 mm)
•Height (in): 27 ½” (700 mm)
•Weight: 47 pounds (21 kg).
Gas types
Natural Gas.
Liquid Propane.
The appliance is not field convertible.
Voltage
120 V AC (50/60 Hz)
Amperage
Idle - 40 mA
Operation - ≤ 1.5 A
Noise
≤ 50 db (A)
Safety devices
•Flame failure device (Ionization flame control)
•Overheat prevention (temperature limiter)
•Pressure switch (blocked vent protection).
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Appliance details
Water resistant
IP X4 (protection against water drops)
2.3Unpacking the GWH-345/450-ESR heater
This heater is packed securely.
The box includes:
•Wall-mounted gas fired recirculating water heater
•Bracket and screws for wall hanging the heater
•Exhaust vent adaptor (with 4 screws and gasket provided)
•Combustion air inlet adaptor (with 4 screws and gasket provided)
•Installation manual
•Product registration card
•Energy Guide label
•Pressure relief valve
•Inlet air restrictors
–GWH 345 ESR N: Ø38/40/42
–GWH 345 ESR LP: Ø38/40/42
–GWH 450 ESR N: Ø44/47/50/55
–GWH 450 ESR LP: Ø47/50/55/60
Do not lose this manual. Please complete and return the enclosed product registration card.
Before installing the unit, be certain you have the correct heater for your type of Gas - Propane or Natural Gas. Identification labels are found on the shipping box, and on the rating plate which is located on the right side panel of the cover.
To remove front cover
The front cover is secured with two
iscrews to prevent unauthorized access. Always secure the control panel and front cover with these screws.
B Loosen the two Philips head screws located as shown in fig. 2.
Fig. 2 Screws
B Pull control panel outwards and then pull it downwards (Fig. 3).
Front cover
Low voltage access cover
Control panel
Fig. 3 Service position to access water and electric connections
B Lift front cover upward and remove.
The GWH-345/450-ESR is not approved or designed for:
•Manufactured (mobile) homes, RV's or boats
•Outdoor installation
•Combination venting with other appliances
•Closed loop heating applications.
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Appliance details
2.4General rules to follow for safe operation
1.You must follow these instructions when you install your heater. In the United States: The installation must conform with local codes or, in the absence of local codes, the National Fuel Gas Code ANSI Z223.1/NFPA 54.
In Canada: The Installation must conform with CGA B149.(1,2) INSTALLATION CODES and /or local installation codes.
2.Carefully plan where you install the heater. Correct combustion air supply and vent pipe installation are very important. If not installed correctly, fatal accidents can be caused by lack of air, carbon monoxide poisoning or fire.
3.When the unit is installed indoors with ROOM SEALED (twin pipe) combustion air and venting, it is permitted to be located in bathrooms, bedrooms and occupied rooms that are normally kept closed. See chapter 3.6. If the unit will be installed indoors and use indoor combustion air, the place where you install the heater must have enough ventilation. The National Fire Codes do not allow UNSEALED gas fired water heater installations in bathrooms, bedrooms or any occupied rooms normally kept closed. See chapter 3.2 and 3.5.
4.You must vent your heater. See chapter 3.6 Venting.
5.The appliance and its gas connection must be leak tested before placing the appliance in operation. The appliance must be isolated from the gas supply piping system by closing its individual manual gas shutoff valve (not supplied with heater) during any pressure testing at pressures in excess of ½ Psig (3.5 kPa).
6.Keep water heater area clear and free from combustibles and flammable liquids. Do not locate the heater over any material which might burn.
7.Correct gas pressure is critical for the optimum operation of this heater. Gas piping must be sized to provide the required pressure at the maximum output of the heater, while all the other gas appliances are in operation. Check with your local gas supplier, and see the section on connecting the gas supply.
8.Should overheating occur or the gas supply fails to shut off, turn off the gas supply at the manual gas shut off valve, on the gas line. Note: manual gas shutoff valve is not supplied with the heater.
9.Do not use this appliance if any part has been underwater. Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control which has been underwater.
10.Failure to install heater correctly may lead to unsafe operation and void the warranty.
11.The heater must not be installed in an unheated area where temperatures will reach 36°F or lower. If the heater is left in an area susceptible to such temperatures, drain the unit and disconnect from electrical supply. See Chapter 4.7 for additional freeze prevention information.
12.In areas where water supply has a high mineral content, a water softener is strongly recommended. A water softener is required if the water hardness exceeds 6 grains/gal (103 mg/l) calcium carbonate. Damage to the water heater resulting from hard water/scale deposits will not be covered under warranty.
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Appliance details
2.5Dimensions and minimum installation clearances
Fig. 4 Dimensions
1 Combustion air inlet adapter (right side only)
2 Exhaust adapter with CO2 measuring point
3Front cover
4 On/Off button
5Reset button
6Recirculating water temperature selector
7 LED - (ON) warning light (blinks when in error lock out)
8Domestic hot water temperature selector
9 Mounting plate
Fig. 5 Minimum clearances
|
Model GWH-345/450-ESR |
TOP |
12” |
FRONT (B) |
4” |
BACK |
0” |
SIDES |
½” |
BOTTOM |
12” |
Table 1 Minimum clearances
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Appliance details
2.6Applications
Caution: the water heater which will be used to supply potable water shall not be connected to any heating system or component(s) previously used with a nonpotable water heating appliance.
Introduction
The application designs provided in this manual are general guides to be used when installing this recirculating water heater.
Pump Sizing
Required PS pumps are Taco 007 Bronze or Grundfos 15-42B. PZ pumps should be sized by a professional plumbing contractor based on the specific application.
Caution: Do not overpump the heater. Maximum 5 gpm water flow permitted through the heater.
Instantaneous water heater (direct tank load design)
Note: maximum amp draw: 1,5A. Do not connect additional pump to the appliance but use a relay panel if powering multiple pumps.
Fig. 6
Front cover
Low voltage access cover
Control panel
Fig. 7 Service position to access water and electric connections
8 |
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Appliance details
Pressure drop curves
Note: Flow above 6 GPM is not permitted.
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50 |
feet of head |
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GWH 345 ESR |
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pressure |
40 |
feet of head |
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30 |
feet of head |
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20 |
feet of head |
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Inlet |
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10 |
feet of head |
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0 |
feet of head |
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0 GPM |
1 GPM |
2 GPM |
3 GPM |
4 GPM |
5 GPM |
6 GPM |
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water flow rate |
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Fig. 8 GWH 345 ESR
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feet of head |
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GWH 450 ESR |
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pressure |
40 |
feet of head |
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30 |
feet of head |
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20 |
feet of head |
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Inlet |
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10 |
feet of head |
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0 |
feet of head |
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0 GPM |
1 GPM |
2 GPM |
3 GPM |
4 GPM |
5 GPM |
6 GPM |
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water flow rate |
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Fig. 9 GWH 450 ESR
2.7Water quality
Water quality can have an impact on appliance performance and appliance longevity, and may not be covered by the manufacturer's warranty.
For water analysis data call your local water department. If on a well system, have well water analyzed periodically. If water quality is exceeding one or more of the values specified below, Bosch recommends installing a water conditioner or softener.
Descri- |
pH |
TDS |
Total |
Aluminum |
Chlorides |
Copper |
Iron |
Manganese |
Zinc |
ption |
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(Total |
hardness |
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Dissolved |
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Solids) |
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Max. |
pH |
mg/l or |
mg/l or |
mg/l or |
mg/l or |
mg/l or |
mg/l or |
mg/l or ppm |
mg/l or |
Levels |
range |
ppm |
ppm |
ppm |
ppm |
ppm |
ppm |
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ppm |
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6.5-8.5 |
500 |
100 (6 |
0.2 |
250 |
1.0 |
0.3 |
0.05 |
5.0 |
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grains) |
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Table 2 Venting Specifications
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9 |
Installation instructions
3Installation instructions
3.1Introduction
Please follow these instructions. Failure to follow instructions may result in:
•Property damage or personal injury
•Improper operation
•Heater damage
•Loss of warranty.
Please contact Bosch Water Heating with any questions.
3.2Proper location for installing your heater
Carefully select the location of the water heater. For your safety and for proper heater operation, you must provide combustion air to the heater and a proper exhaust vent system.
Follow the guidelines below:
B 1. Locate the heater where venting, gas and plumbing connections are feasible and convenient.
B2. The hot water lines should be kept short to save energy. Centrally locating the water heater is best. It is always best to have hot water lines insulated.
Warning: The water in this recirculating water heater is cold and always remains cold except for the times the burners are on. In the event of power outage in conjunction with freezing temperatures, it is recommended that the heater be drained to prevent heater from freezing. See chapter 9 for draining instructions.
Warning: Flammable materials, gasoline, pressurized containers, or any other items or articles that are potential fire hazards must NOT be placed on or adjacent to the heater. The appliance area must be kept free of all combustible materials, gasoline and other flammable vapors and liquids.
3.3Heater placement and clearances
The GWH-345/450-ESR is design certified for installation on a combustible wall (see 3.4 Mounting installation) provided the floor covering below the heater is noncombustible. For installations in an alcove or closet, maintain the minimum clearances to combustible and non-combustible materials listed below. See also fig. 5.
A.Top 12 inches (305 mm)
B.Front 4 inches (100 mm)
C.Back 0 inches
D.Sides ½ inches (12 mm)
E.Bottom 12 inches (305 mm)
Clearances from any exhaust vent pipe are dependent upon the clearance requirements of the stainless steel vent pipe manufacturer. Single wall sealed stainless steel (AL29-4C) vent pipe (rated for Category III appliances) must be used when exhaust venting this appliance. See 3.6 Venting.
3.4Mounting installation
Warning: before starting installation:
B check that there are no loose parts inside the appliance
Bcheck that the gas type of the heater matches the gas supply you will be connecting to the heater.
Bensure that gas pipe, gas valve, fan and burner have no damage and are properly fitted.
i |
Front cover should be removed (see |
instructions on page 5) in order to inspect |
|
components visually. |
BSecure the wall mounting bracket provided with the heater to a wall surface.
Warning: Do not install this appliance on a carpeted wall. The heater must be mounted on a wall using appropriate anchoring materials.
If wall is a stud wall sheathed with plasterboard, it is recommended that support board(s), either 1x4’s or
1/2" (minimum) plywood first be attached across a pair of studs. Then attach the heater’s bracket to the upper support board. The heater should be kept level on the wall surface. See Fig. 10.
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Installation instructions
Fig. 10 Mounting the heater
3.5Combustion air requirements
Warning: In areas where freezing temperatures are common the twin pipe system is recommended. In a single pipe installation, a negative air condition may result in cold air being drawn across the heat exchanger coil causing it to freeze and burst. This failure is not covered under the manufacturer’s warranty.
Warning: When installed in an environment where corrosive chemicals or dirty air are present the twin pipe system is required.
Twin pipe
The GWH-345/450-ESR is designed as a sealed combustion appliance. It is recommended that the combustion air be provided by a dedicated 3” pipe to the outside. If terminating combustion air piping horizontally, pitch vent down 1/4" per foot towards termination to prevent rain from entering the appliance. The combustion air pipe may be constructed of aluminum flex, PVC or any other rigid or semi rigid sealed pipe. The combustion air inlet must be located in such a manner as to provide a minimum 3 foot clearance from the exhaust vent terminator.
The maximum length of the combustion air inlet is 39 feet with one elbow. Subtract 6 feet for each additional elbow. Maximum number of elbows permitted is 4.
Single pipe
Although it is permissible to draw combustion air from inside the structure, it is not the manufacturer’s recommended installation method. Always install a 3 inch elbow on the combustion air inlet to prevent foreign objects from falling into the unit (see Fig. 11).
Fig. 11
If a single pipe installation is performed. Use the following guidelines when providing adequate combustion air for the recirculating water heater as well as any other appliances that may consume air in the space. Always follow local codes if more stringent.
•Appliances located in unconfined spaces:
–a) An unconfined space is one whose volume is greater than 50 cubic feet (1.42 cubic meter) per 1000 Btu per hour (292.81 watts) of the combined rating of all appliances installed in the space. That would be 6200 cubic feet (175.6 cubic meter) of air required for the GWH-345/ 450-ESR alone.
–b) In unconfined spaces in buildings of conventional frame, masonry, or metal construction, infiltration air is normally adequate to provide air for combustion.
–c) Installations in structures that have been tightly constructed (air infiltration rate of 0.40 ACH or less) must provide combustion air per the National Fuel Gas Code. Consult an HVAC specialist if your air infiltration rate is questionable. For these types of installations, the twin pipe system must be used.
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Installation instructions
•Appliances located in confined spaces:
The confined space must be provided with two permanent openings, one commencing within 12 inches (304.8mm) of the top and one commencing within 12 inches (304.8mm) of the bottom of the enclosure. Each opening must have a minimum free area of one square inch per:
–1000 Btu/hr (292.81 watts) if all air is taken from inside the building
–2000 Btu/hr (585.62 watts) if all air is taken from the outside by horizontal ducts
–4000 Btu/hr (1171.24 watts)if all air is taken from the outside by direct openings.
Or the confined space must be provided with one permanent opening or duct that is within 12 inches (304.8mm) of the ceiling of the enclosure. This opening must have a minimum free area of one square inch per:
–3000 Btu/hr (878.43 watts) if all air is taken from the outside by a direct opening.
Louvers, grills and screens have a blocking effect, when used, increase the sizes of your openings by 400% for wood louvers (as wood type will reduce the free air by 75%) and 135% for metal louvers (as metal will reduce the free air by 30%). Refer to the National Fuel Gas Code for complete information.
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