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TM
MODELS DB/DW-720-1810
Built tough with maximum efficiency
NATURAL GAS-FIRED COMMERCIAL CROSS FLOW COPPER BOILERS
FOR HYDRONIC HEATING AND HOT WATER SUPPLY
WITH ELECTRONIC INTERMITTENT PILOT IGNITION AND
INSTALLATIONS
INSTALLATION OPERATION MAINTENANCE LIMITED WARRANTY
WARNING: If the information in this manual
is not followed exactly, a fire or explosion may
result causing property damage, personal
injury or loss of life.
— Do not store or use gasoline or
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CONTENTS Page Page FOREWORD ................................................................................ 2 Low Water Cutoff ..................................................................... 14 REPLACEMENT PARTS .............................................................. 2-3 Tank Temperature Control ........................................................ 14 ROUGH-IN DIMENSIONS/CAPACITIES ...................................... 3-4 SYSTEM INSTALLATION ......................
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CAUTION Two inch clearance is allowable from combustible construction for Label all wires prior to disconnection when servicing controls. Wiring hot water pipes. errors can cause improper and dangerous operation. Sufficient clearance should be provided at one end of the boiler to permit access to heat exchanger tubes for cleaning. Maximum "Verify proper operation after servicing." operating water supply pressure 160 psi. Gas supply pressure: 13.8" w.c. max., 5.5" w.c. min. ROUGH-IN DIMENSIO
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WARNING Your Dura-Max boiler is not designed to operate with a boiler inlet water temperature of less than 100°F (38°C). Colder inlet water temperatures will result in significant condensation developing on the heat exchanger. This situation can cause a corrosive environment for the heat exchanger, burners and venting resulting in premature damage, which could result in serious personal injury or death. For systems that use large volumes of cold water or system utilizing heavy water draws (
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and pilot gases are cut off during the “OFF” cycle. Pilot gas ignition FEATURES is proven by the pilot sensor. Main burner ignition will not occur if the pilot sensor does not first sense pilot ignition. IMPORTANT Only qualified personnel shall perform the initial firing of the heater. At this time the user should not hesitate to ask the individual any questions regarding the operation and maintenance of the unit. Lighting and Operating instructions are included at the rear of this manual. By
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The heater operation with above set points will be as follows: AUTOMATIC RESET HIGH TEMPERATURE LIMIT CONTROL 1) When heater temperature rises to LO thermostat setting the main gas valve will close its second stage operator to drop CAUTION input to approximately 50% of total input. LIMIT CONTROLS ARE NOT TO BE USED AS THERMOSTATS. ALL MODELS - This limit is a safety device wired in series with the 2) System conditions will determine if temperature rise at LO ignition system. Set the limit c
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If the boiler is installed above the level of heating system terminal INSTALLATION INSTRUCTIONS units, a low water cutoff device must be installed in the boiler outlet at the time of installation. REQUIRED ABILITY For installation locations with elevations above 2,000 feet (610 M), refer to the HIGH ALTITUDE INSTALLATIONS section of this INSTALLATION OR SERVICE OF THIS BOILER REQUIRES manual for input reduction procedure. ABILITY EQUIVALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD INVOLVED.
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If the confined space is within a building of tight construction, air for 1. DRAFT HOOD combustion, ventilation, and draft hood dilution must be obtained The integral draft hood, louvers or cabinetry must not be altered. from outdoors. When directly communicating with the outdoors or Provision must be made if the boiler is installed in confined space communicating with the outdoors through vertical ducts, two or a small boiler room to accommodate draft hood spillage and permanent openings, loca
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WARNING GAS CONNECTIONS FAILURE TO CORRECT BACK DRAFTS MAY CAUSE AIR CONTAMINATION AND UNSAFE CONDITIONS. WARNING THIS BOILER IS NOT INTENDED TO OPERATE AT GAS SUPPLY Vent connectors serving appliances vented by natural draft shall PRESSURE OTHER THAN SHOWN ON THE RATING PLATE. not be connected into any portion of mechanical draft systems EXPOSURE TO HIGHER GAS SUPPLY PRESSURE MAY CAUSE operating under positive pressure. DAMAGE TO GAS VALVES WHICH CAN RESULT IN FIRE OR EXPLOSION. IF OVERPRE
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2A. SIZING GAS SUPPLY LINE (For single boiler installations PURGING and for installations of multiples of two or three of same size boilers). Gas line purging is required with new piping or systems in which air has entered. Use table 1, which is taken from ANSI booklet Z223.1, NATIONAL FUEL GAS CODE, and/or CAN/CSA-B149.1-00 to size iron pipe CAUTION or equivalent gas supply line. Table 4 is based on a pressure drop PURGING SHOULD BE PERFORMED BY PERSONS of 0.3 inches of water and a specific
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Applications of the gravity factor converts the figures given in table HIGH ALTITUDE INSTALLATIONS 1 to capacities with another gas of different specific gravity. Such application is accomplished by multiplying the capacities given in IN CANADA table 1 by the multipliers shown in table 5. Acceptance of these models for use at altitudes above 2000 feet (610 m) is based on field test of the individual installation by the To determine the size of each section of gas piping in a system within the r
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IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED WITH THE SYSTEM HEADERS APPLIANCE, MUST BE REPLACED, IT MUST BE REPLACED Split systems with individual supply and return lines from the boiler WITH TYPE 105°C WIRE OR ITS EQUIVALENT, EXCEPT FOR room should normally have this piping connected to supply and THE FLAME SENSOR AND IGNITION CABLE WHICH ARE 250°C. return manifold headers near the boiler. To achieve good water distribution with minimum pressure drop for several circuits, SERVICING WIRING AND/OR
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FIGURE 8 The flow switch shall be mounted in the top opening of the reducing THE CIRCULATING PUMP MUST BE PROPERLY SIZED FOR tee and provide adequate paddle length in the flow stream. For YOUR APPLICATION. example in a 2" pipe installation use a 2" x 2" x 1" reducing tee. For 2" or 3" pipe use the paddle segments as supplied. For other pipe Water hardness, system pressure drop and temperature rise across sizes (i.e. 2-1/2") trim the paddle to the proper pipe size, see fig. 8. the boiler all a
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Thereafter, during the heating season, lubricate the three oil cups all cases, that the water temperature be set for the lowest at least once every four months. Combination heating/cooling temperature which satisfies the user's hot water needs. This will also provide the most energy efficient operation of the water heater systems or water heating (Cer-temp) systems should be lubricated and minimize scale formation. every four months year-round. SETTING THE WATER TEMPERATURE AT 120°F (49°C) WIL
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A system bypass should be installed as shown in fig. 10 to prevent determine if boiler will shut down or if unit will return smoothly to boiler circulation starvation when the system zones call for reduced full input. flow. Dura-Max models may also be equipped with modulation which This bypass may also be used with multiple boilers manifolded for automatically adjusts the boiler output to match the system heat reverse-return flow. The system bypass would be installed from loss and variations of
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NOTES: 1. BUILDING TEMPERATURE CONTROLS SUPPLY ELECTRIC POWER TO BUILDING CIRCULATOR. 2. MAIN FLOW SWITCH PROVES MAIN WATER FLOW BEFORE ENERGIZING, SEQUENCING AND RESETTING CONTROLS. 3. OUTDOOR THERMOSTAT REQUIRED IF BUILDING CONTROLS DO NOT PROVIDE AUTOMATIC SHUT-DOWN OF RESET CONTROLS DURING WARM WEATHER. 16
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BYPASS BALANCING Figure 11 shows a typical field wiring diagram for a single stage LINEAR-TEMP installation. The boiler may be controlled boiler With systems where water temperature can be expected to drop by a main temperature controller as shown or may include outdoor appreciably due to long standby periods, or heavy draw down, a reset if desired. bypass pipe of at least 1" size with a balancing cock should be installed between the boiler inlet and outlet (see fig. 10). When The following
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generator type boilers establish temperature rises. The deciding boiler(s). Make-up water connections, and accessories are not factor in choice of boiler temperature rise relates to the boiler inlet shown. temperature. Boiler outlet, minus system temperature drop, is Supply and return headers of the old system should be connected boiler inlet temperature. THE BOILER TEMPERATURE RISE to the boiler loop with a pair of tees set close together. The boiler SHOULD NOT RAISE THE OUTLET TEMPERATURE
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TABLE 8. NO. SUGGESTED ITEMS FOR INSTALLATION 1. SHORT PIPE NIPPLE AND PAIR OF BOILER LOOP TEES IN PIPING BETWEEN SYSTEM SUPPLY AND RETURN - ONE SET PER EACH BOILER 2. BOILER PIPE LOOP (See Piping Sizing Data Table 3.) 3. BOILER CIRCULATING PUMP (See Piping Sizing Data Table 3.) 4. THERMOMETER 5. PRESSURE GAUGE 6. LOW WATER CUT-OFF (If Required By Local Code.) 7. SAFETY FLOW SWITCH 8. RELIEF VALVE (Furnished with Boiler) 9. BOILER INLET - OUTLET 10. SYSTEM SUPPLY TEMP
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USE ONY TYPE 105°C THERMOPLASTIC OR ITS EQUIVALENT IF ANY OF THE ORIGINAL WIRES AS SUPPLIED MUST BE REPLACED. BOILER CONVENTIONAL SYSTEM FIGURE 15 USE ONY TYPE 105°C THERMOPLASTIC OR ITS EQUIVALENT IF ANY OF THE ORIGINAL WIRES AS SUPPLIED MUST BE REPLACED. ONE BOILER LINEAR-TEMP SYSTEM FIGURE 16 20
