followed by
10.If a flame is detected, stage two will be activated and start its blower. Once the blower air has been proven, igniter two will begin trial for ignition cycle as above, (this is not the case for model 1000, which has only one igniter).
11.Stage three will activate upon flame detection on stage two. The gas valve will open five seconds following call for heat and gas flow will continue if flame signal is detected. (On 4- stage firing system, the blower associated with stage three will start and once the blower air has been proven, the ignition cycle will take place as above. If flame is not proven, a 15- second
12.All stages will remain running until the set point for a given stage is satisfied. The last stage will drop out first followed by inter- stages then stage one will drop out last. Note: Once a stage is satisfied, the blower associated with that stage will continue for
13.Once all the stages have been satisfied, the boiler pump will continue to run for the programmed
14.The control now enters the idle state as displayed by the "Standby" LED. The control will continue to monitor heat demand and state of other system devices. Upon a drop of water temperature below the set parameters, the control will return to step 5 and repeat the entire operating cycle. Note: Any fault detection, during standby or running modes, will halt the heating sequence and shift the system to the service mode where the detected fault will be displayed.
NOTE: In standby and running modes the system constantly monitors the signals and the internal operation for faults. Any detected fault will halt the heating sequence and shift the system to the service mode, where the detected fault will be displayed.
Temperature Setpoints (System Control Algorithm)
The boiler has a hysteresis type control, which means that it will begin heating the water when the temperature sensed by the control probe (inlet or tank) falls below the operating setpoint minus the differential setpoint for stage 1. It will stop heating the water when the temperature rises to the operating setpoint. If the system has multiple stages then the differential setpoint for each stage is also subtracted from the operating setpoint. The following examples will further explain this operation.
Setup: 2 stage system, operating setpoint - 140, stage 1 to 2 differential setpoints = 10.
Example 1. Temperature begins at 150 and drops to 90, see Figure 20A. At 140 the system remains in idle mode. As the temp drops to 130
Example 2. Temperature begins at 90 and rises to 150, see Figure 20B. At 100 both stages are on. (This is the case when a boiler is first started and the controlling temperature is below the operating setpoint minus all of the differential setpoints. At that time both stages are turned on, in sequence from 1 to 2. At 130 stage 2 turns off. At 140 both stages are off.
Stages 1 and 2 will turn on in sequence from 1 to 2.
FIGURE 20 A. | FIGURE 20 B. |
UIM OPERATING PROCEDURES
FIGURE 21. UIM, USER INTERFACE MODULE
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. The LCD provides information to the user by the use of 10
UIM Screens:
On all screens a double vertical bar appears on the right side of the display each time a key is touched to indicate that a key has been activated. On several screens an indicator ">" appears on the left side of the display to indicate the active line. The "Up/Down" keys are used to move the indicator to the desired line and the "Select" key is pressed to select the line. Also, on most of the screens, up/down arrows appear on the right side of the screen to indicate that there is additional lines either above or below the displayed four lines.
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