GAS-FIRED COPPER BOILERS FOR HYDRONIC HEATING AND HOT WATER SUPPLY • • • • INSTRUCTION MANUAL MODELS: VB/VW-500, 750 AND 1000 Installation Operation Maintenance Limited Warranty SERIES 100/101 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 other flammable vapors and liquids in the vicinity of this or any other appliance.
SAFE INSTALLATION, USE AND SERVICE Your safety and the safety of others is extremely important in the installation, use, and servicing of this boiler. Many safety-related messages and instructions have been provided in this manual and on your own boiler to warn you and others of a potential injury hazard. Read and obey all safety messages and instructions throughout this manual.
GENERAL SAFETY 3
DIMENSION AND CAPACITY DATA Minimum clearances to combustibles: • 4” (102mm) rear • 0” (0mm) top & sides • 6” (152mm) vent FIGURE 1. TABLE 1, GAS AND ELECTRICAL CHARACTERISTICS Manifold Pressure Maximum Supply Pressure Minimum Supply Pressure Model Type of Gas Inches W.C. kPa Inches W.C. kPa Inches W.C. kPa VB/VW-500, 750, 1000 NATURAL -2 to 3.5 -.5 to .9 11.0 3.44 4.0 2.0 VB/VW-500, 750, 1000 PROPANE -2 to -3.5 -.5 to .9 13.8 3.44 8.0 2.
CAPACITY AND FLOW DATA TABLE 3. RECOVERY CAPACITIES. Model No.
CONTENTS SAFE INSTALLATION, USE, AND SERVICE ................................. 2 GENERAL SAFETY .......................................................................... 3 DIMENSION AND CAPACITY DATA ............................................ 4-5 TABLE OF CONTENTS ................................................................... 6 INTRODUCTION ............................................................................ 6-7 Grounding Instructions .........................................................
GROUNDING INSTRUCTIONS LP gas is present or even suspected, do not attempt to find the cause yourself. Leave the building, leaving doors open to ventilate, then call your gas supplier or service agent. Keep area clear until a service call has been made. This boiler must be grounded in accordance with the National Electrical Code and/or local codes. Boiler is polarity sensitive; correct wiring is imperative for proper operation. At times you may not be able to smell an LP gas leak.
FEATURES THE CONTROL SYSTEM The high BPS closes only when the blower is in pre and post purge. If the high BPS closes at any time during the heating cycle, the boiler will shut off. The control system consists of four basic components: 1) Modulation Control Board (MCB); 2) Power Distribution Board (PDB); 3) Variable Frequency Drive (VFD), see Figure 2; 4) User Interface Module, see Figure 19.
WATER TEMPERATURE LIMIT CONTROLS FOR HOT WATER HEATING BOILERS-VB models, a remote probe is supplied due to the various types of systems and operating conditions. A remote probe can be used as an option to control loop temperature and unit staging. Additionally, the inlet temperature probe can be used as the loop thermostat in some heating applications. The remote probe connects to designated wires in the junction box at the rear of the boiler, refer to the PROBE INSTALLATION section.
location. A drain line must not contain any valves between the boiler and the relief valve, or the relief valve and the drain exit. In addition, there should not be any restrictions in a drain line nor should it be routed through areas where freezing conditions might occur. Do not thread or cap the drain line exit. Restricting or blocking a drain line will defeat the purpose of the safety relief valve and may create an unsafe condition.
shall be wide enough to allow the boiler to enter or to permit the replacement of another appliance such as a boiler. LEVELING Each unit should be checked after installation to be certain that it is level. If the unit is not level, obtain and insert shims under the feet at the frame base to correct this condition. AIR REQUIREMENTS FIGURE 8. CHEMICAL VAPOR CORROSION Boiler corrosion and component failure can be caused by the heating and breakdown of airborne chemical vapors.
communicating with the outdoors. The installation instructions for confined spaces in tightly constructed buildings must be followed to ensure adequate air supply. permanent openings, located in the aforementioned manner, shall be provided. Each opening shall have a free area of not less than one square inch per 4000 Btu/hr (551mm2 per kw) of the total input of all appliances in the enclosure.
VERTICAL INSTALLATION REQUIREMENTS from the horizontal to vertical run. This is where the bottom most support bracket should be located. 1. The vent system must terminate at least 3 feet (1.0m) and no more than 6 feet (2.0m) above the roof line and no closer than 10 feet (3.0m) from any wall or vertical structure. If the exhaust vent terminal is within 10 feet (3.0m) of a wall or parapet, it must extend a minimum of 2 feet (610mm) above the wall or parapet, see Figures 11 and 12A.
NOTES: If the exhaust vent terminal is within 10’ (3.0m) of a wall or parapet, it must extend a minimum of 2’ (610mm) above the wall or parapet. Joints are not joined to show vent pipe orientation. FIGURE 11. VERTICAL TERMINATION. NOTES: Joints are not joined to show vent pipe orientation. FIGURE 11A. HORIZONTAL THROUGH THE WALL TERMINATION (TWT).
DIRECT VENT INSTALLATION REQUIREMENTS 1. The Air-Intake System (AIS) must terminate with the venting equipment provided with the boiler, Refer to the parts list for required direct vent parts. Follow the guidelines in the “HORIZONTAL INSTALLATION REQUIREMENTS” section for the exhausting of flue products. IMPORTANT 2. The AIT shall not be located less than 3 feet (1.0m) below any exhaust vent within 10 feet (3.0m), see “HORIZONTAL INSTALLATION REQUIREMENTS” section.
NOTE: Joints are not joined to show vent pipe orientation. CAUTION Direct venting into dead air spaces such as alleys, atriums, and inside corners can cause recirculation of flue gases. Recirculation of flue gases will cause sooting, premature failure of the heat exchanger and icing of the combustion air intake during severe cold weather. To prevent the recirculation of flue gases, maintain as much distance as possible between the combustion air intake and the exhaust vent terminal. FIGURE 12.
Option B (Figures 11B & 11C) assures no recirculation of flue gases. 70 EQUIVALENT FEET (27.4m) OF VENTING (MAX.) AL 29-4C® AIR INTAKE TERMINAL HORIZONTAL AIR INTAKE NOTES: PVC PIPE 70 EQUIVALENT FEET (27.4m) • IF THE EXHAUST VENT TERMINAL IS WITHIN 10’ (3.0m) OF A WALL OR A PARAPET, IT MIUST EXTEND A MINIMUM OF 2’ (0.6m) ABOVE THE WALL OR PARAPET. • ON SIDEWALL VENT INSTALLATION, REFER TO FIGURE 7 FOR SPACING SPECIFICATIONS • FOR EXHAUST AND AIR INTAKE PIPE INSTALLATIONS (CLEARANCES, SUPPORT, ETC.
SYSTEM INSTALLATION GENERAL If the system is to be filled with water for testing or other purposes during cold weather and before actual operation, care must be taken to prevent a downdraft entering the boiler or freezing air from contacting the system. Failure to do so may cause the water in the system to freeze with resulting damage to the system. DAMAGE DUE TO FREEZING IS NOT COVERED BY THE WARRANTY. Good practice requires that all heavy piping, etc., be supported.
HOT WATER SUPPLY BOILER SYSTEMGENERAL WATER LINE CONNECTIONS 7. SYSTEM CONTROLLER Controlling of these systems is decided mainly by the type of building system controlling desired. A single boiler installation might be controlled directly from space temperature thermostat(s). Multiple boiler installations are more effective when the boilers are sequenced in and out of operation by some form of main water temperature controller.
DANGER TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE AT FIXTURES. IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN ANTISCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES, SEE TABLE 11. • INSTALL IN ACCORDANCE WITH ALL LOCAL CODES. • WHEN BLOW DOWN VALVE IS REQUIRED, INSTALL IN PLACE OF THE DRAIN VALVE SHOWN. FIGURE 13. TYPICAL PRIMARY, SECONDARY PIPING. may cause damage to gas valves which can result in fire or explosion.
ONE VF (MODEL VW) HOT WATER SUPPLY BOILER WITH VERTICAL TANK DANGER TEMPERATURE SETTING SHOULD NOT EXCEED SAFE USE TEMPERATURE AT FIXTURES. IF HIGHER PREHEAT TEMPERATURES ARE NECESSARY TO OBTAIN ADEQUATE BOOSTER OUTPUT, ADD AN ANTI-SCALD VALVE FOR HOT WATER SUPPLIED TO FIXTURES, SEE TABLE 11. INSTALL THERMAL EXPANSION TANK ON COLD WATER SUPPLY LINE, IF CHECK VALVE OR PRESSURE REDUCING VALVE IS USED IN SUPPLY. FIGURE 14.
To prevent damage, care must be taken not to apply too much torque when attaching gas supply pipe to boiler gas inlet. Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Fittings and unions in the gas line must be of the metal to metal type. Verify proper operation after servicing. Strict adherence to the wiring diagrams is required to prevent constant pump operation when the system controller is satisfied.
10 (3.05) 680,000 199 1,400,000 410 2,100,000 615 3,950,000 1,157 6,300,000 1,845 11,000,000 3,222 23,000,000 6,736 20 (6.1) 465,000 136 950,000 278 1,460,000 428 2,750,000 805 4,350,000 1,274 7,700,000 2,255 15,800,000 4,627 Nominal Iron Pipe Size (Inches) 1 BTU/hr kW 1 1/4 BTU/hr kW 1 1/2 BTU/hr kW 2 BTU/hr kW 2 1/2 BTU/hr kW 3 BTU/hr kW 4 BTU/hr kW 10 (3.05) 1,060,800 311 2,184,000 640 3,276,000 959 6,162,000 1,805 9,828,000 2,878 17,160,000 5,026 35,880,000 10,508 20 (6.
FIGURE 18.
VB/VW-500, 750 & 1000 SCHEMATIC DIAGRAM FIGURE 17 - SCHEMATIC DIAGRAM 26
OPERATION IMPORTANT Only qualified personnel shall perform the initial firing of the boiler. At this time the user should not hesitate to ask the start-up technician any questions regarding the operation and maintenance of the unit. If you still have questions, please contact the factory or your local A.O. Smith representative. Lighting and Operating instructions are included with this manual.
The boiler should be located in an area that is inaccessible to the general public. Never allow small children to use a hot water tap or to draw their own bath water. Never leave a child or handicapped person unattended in a bathtub or shower. TABLE 9. Risk of Scalds.
MCB - Ten Position Dipswitch: Dipswitch configurations are READ ONLY ON POWER UP. These switches are only to be set at the factory or by authorized trained personnel! Once set the boiler will operate according to the chosen options. If a switch is changed, power must be cycled before the change will take effect. The status of all dipswitches can be observed on the system status screen on the UIM.
LIGHTING & OPERATION INSTRUCTIONS FOR MODELS VB/VW 500, 750 AND 1000: 30
ADJUSTMENT LOW FIRE SETTING NATURAL 6.5 - 7.5% PROPANE 7.5 - 8.5% Set boiler to the “Test Mode Low,” as described above, to achieve minimum firing rate of the boiler. Check combustion readings using a combustion analyzer. If combustion readings are not in accordance with the chart shown above adjust as follows: remove the cap on the gas regulator using a slotted screwdriver. This will expose the offset adjustment screw.
INPUTS TO MCB Gas Valve (MCB - 24VAC - required): Provides power to activate the gas valve. The gas valve cannot be activated when the ECO contacts are open. TEMPERATURE SENSORS: Temperature probes (MCB - outlet and either inlet or tank are required): The MCB accepts analog temperature inputs from up to three sensors (inlet, outlet, and tank). Low Water Cut Off (MCB - 24VAC - optional): Directly connected to the 24VAC line to provide power to operate an external LWCO device.
5. The heating sequence begins by applying power to the pump. 6. After a few seconds the blower is turned on for 30-second pre-purge period of combustion chamber. 7. The igniter is turned on. 8. After the igniter has reached a minimum of 2.8 amps, the gas valve is energized to allow gas flow to burner. The UIM receives commands from the user and displays operational information to the user via an LCD (liquid crystal display) up to eleven LED's, and five touch switches.
for a heat request (determined by the Thermostat or controlling probe inputs). All outputs are off in this state except that if the Post-Circulate time is set to continuous, the pump will be on. When the heat request is received, the system moves to the PreCirculate state. • Pre-Circulate: The yellow LED is turned off and the green "Running" LED is turned on. The green LED will remain on for all other states except the fault states.
• • if the blower prover does not activate after 15 seconds. This time allows the blower relay to activate, the blower to come up to speed, and the response from the blower prover to be filtered. 5. Press the SELECT KEY. User Settings Screen: Each setpoint or user setting has either a limited selection of values, or a limited range of values. The Up/Down keys are used to change values.
• • • The software revision level of the MCB. Current Error Screen: Displays the last error that the system has detected plus a time stamp of when the error occurred. (The time stamp is based on the elapsed hours value at the time the error occurred. It is displayed in hours and minutes. This error remain displayed as long as it is still valid. When cleared it is moved to the Error History Screen. The system will automatically jump to this screen when an error is detected.
TROUBLESHOOTING IGNITION SYSTEM Fault Messages and Lockout Status (* = stage number: 1, 2, 3, or 4) FAULT DISPLAYED DESCRIPTION RED LED LOCKOUT “Display Fail” Communications with UIM interrupted Continuous Auto Reset Check communication cable to UIM. Try moving to other Internal Communications connector on MCB. Also check the connectors where the cable is plugged in for best connecting wires. “Comm. Fail Stg.*” Communications with FCB interrupted Continuous Same as above.
TROUBLESHOOTING GAS VALVE Problem: Gas OK, no burner start up (both shutoff valves are open, fan turns) There is not enough gas to accommodate a start up. Turn throttle screw ½ turn counterclockwise and try to start again with more gas. Problem: Non-linear CO2 curve on adjusted boiler (deviation more than 3-6%) 1. Possible blockage at the air inlet that prevents uniform, constant air flow. 2. The gas inlet pressure is too low at full load.
or on the blower and motor. Buildups of dirt and lint on the blower and motor can create excessive loads on the motor resulting in higher that normal operating temperatures and possible shortened service life. BURNER MAINTENANCE Qualified servicers should follow this procedure when the boiler’s burner needs cleaning. 1. Turn off the electrical power to the boiler and close the main manual gas shutoff valve(s). Allow the boiler parts to cool before disassembly.
HEAT EXCHANGER PREVENTIVE MAINTENANCE lines with air or water and clear or replace the blocked portions of the line as necessary. Note that areas of the drain line which include a sag or low spot in the line will also form a condensate trap which can be removed by levelling the tube and does not indicate a blocked system. In most water supply systems solids exist. As the water is heated, these tend to drop out depositing as scale or lime.
NOTES 41
NOTES 42
LIMITED WARRANTY A. O. Smith Corporation, the warrantor, extends the following LIMITED WARRANTY to the owner of this boiler: 1. If within TEN years after initial installation of the boiler, a heat exchanger or gas burner shall prove upon examination by the warrantor to be defective in material or workmanship, the warrantor, at his option will exchange or repair such part or portion. This term is reduced to FIVE years if this boiler is used for water heating purposes other than hydronic space heating. a.
500 Tennessee Waltz Parkway, Ashland City, TN 37015 Phone: 800-433-2545 www.hotwater.com E-Mail: parts@hotwater.
