Évaluations - 3, GPA: 4
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Facilité d'utilisation
See the Water Piping section for minimum and maximum water flow rates and pump selection. NOTE: Pump will come on when power is first applied to the boiler. 42 Blower Fan Pre-purge The CPW board has a built-in pre-purge delay which operates the blower fan for a user-adjustable time period prior to pilot trial for ignition. The pre-purge period ensures that the combustion chamber is clear of all excess combustible gases prior to commencing the pilot ignition cycle. The pre-purge delay is factory set for 45 seconds and it can be adjusted in the field from 45 seconds to 120 seconds. To optimize boiler response time on call-for-heat, set the pre-purge delay to the minimum allowed by local, state or national code. Blower Fan Post-purge The CPW board has a built-in post-purge delay to exhaust residual combustion products after the main gas valve closes. The post-purge timing is factory set at 3 minutes and is not field-adjustable. Freeze Protection Feature The CPW board is programmed to turn-off the blower in case there is a lock-out condition. If there is a call for heat signal, and the pilot valve signal is removed and not reactivated within a pre-set time for any reason, the CPW board will turn off the blower to prevent blowing cold air continuously and freezing the heat exchanger. The blower drives will open and the system will lock in the off state. To restart the system, primary power or the thermostat signal must be turned off and back on. The pre-set freeze protection feature time is approximately 5 minutes. U-2 Diagnostics Board The U-2 Diagnostics board is a solid-state electronic fault indicator that has been engineered to enhance safety, simplify troubleshooting and minimize equipment down time. The U-2 safety board is the central point for wiring, operations monitoring, and fault indication for the boiler safeties. By having each safety report directly to the U-2 board, each safety function can be individually monitored. The U-2 adds complete diagnostics features that aid in the rapid diagnosis of irregularities in boiler operation. A single U-2 Diagnostics Board can monitor a maximum of eight safeties at one time. If, due to code requirements, more than eight safety devices must be monitored, two or more boards will be used to provided extended diagnostics capabilities. Advanced Design Boilers equipped with the standard safety suite will utilize the configuration shown in Table T. The U-2 safety board has a series of red LED lights to indicate a fault occurring at a monitored safety. An additional light indicates that the diagnostics board is energized and is currently monitoring for safety faults. (In order to prevent spurious alarm conditions, the U-2 board monitors safeties only during the actual firing cycle.) Once a fault has been detected, the U-2 board will illuminate the corresponding LED lamp, will shut-down the boiler, and will light the flashing red LED “Service” lamp on the CPW board. If more than one fault is detected, the U-2 board will display the priority fault based on the safety hierarchy as labeled on the U-2 board. Once the first fault is cleared, the second fault lamp will illuminate until cleared. WARNING: Only qualified persons shall attempt to repair the boiler. Improper adjustment, service or maintenance may damage the equipment, create a hazard resulting in asphyxiation, explosion, fire, electric shock, personal injury or property damage, and will void the warranty. Light Color Indication System Enabled Yellow U-2 Diagnostics safety board is functional. Manual High Limit Red Water temperature is over the manual high limit setting. Auto High Limit Red Water temperature is over the auto high limit setting. Flow Switch Red Water flow rate is too low. Low Water Cut-off (option) Red Insufficient water volume for boiler operation. High/Low Gas Pressure Red Gas supply pressure is below or above the allowed minimum gas supply pressure to ensure safe operation. Burner High Limit Red Mixer or PVC vent pipe, if installed, is over heated. Blower/Ignition Lockout Red Blower failure, not enough combustion air or the equipment has an ignition lock-out condition. Blocked Vent Red The vent pressure switch has detected a blocked vent. Table T: U-2 Diagnostic Board LEDs 43 WIRING DIAGRAM 44 Ignition Control Module The intermittent ignition device conserves energy by automatically extinguishing the pilot when the desired temperature is reached. When additional heat is needed, the combustion air blower starts to purge all air from the combustion chamber for about 45 seconds. On proof of air flow, the air proving switch closes and the pilot reignites electrically, eliminating the fuel costs of maintaining a constant pilot. To ensure safe operation, the gas valve cannot open until the pilot relights and is verified. The 100% pilot safety is an electronic device which closes the main gas valve within 8/10 of a second whenever the pilot flame is interrupted. Pilot flame is automatically lit when th...