PC Program Instructions
6Parameters (continued)
Tank differential temp
This parameter determines how far below the tank setpoint the tank sensor temperature must go to start a HW call for heat. This setting can be adjusted by accessing parameter 4AT. The temperature range is 0°F (0°C) to 100°F (38°C). The default value is 5°F (3.5°C).
Time to switch between HW and SH (SH/HW sw tim)
This feature sets the length of time the control will stay in HW mode when a SH call has been received. After this time period has expired the control will determine if a SH call needs to be serviced. If the System Supply Temperature is below the
Boost function time (Boost Tim)
This function will only work if the outdoor air sensor is connected. The Boost Function Time sets the amount of time that must elapse during an SH demand before the water temperature setpoint will be increased. This parameter can be changed by accessing parameter 4AV. The time range for this parameter is 1 minute to 60 minutes. The default value is 20 minutes.
Boost function temp increase (Boost incr)
This function will only work if the outdoor air sensor is connected. If a SH demand lasts longer than the programmed time setting in parameter 4AV, and there have been no HW demands, the control will increase the water temperature setpoint by the amount in this parameter. If the SH demand continues through another time period, the setpoint will be increased again. This will continue until either the SH demand ends, a maximum of 20 increases has occurred, or the maximum user setpoint has been reached. Once the SH demand has been satisfied the setpoint will revert back to its calculated setting. The boost temperature can be changed by accessing parameter 4AW. The temperature range of this parameter is 0°F to 45°F(25°C). The default value is 0°. This feature will be active if this parameter is set to anything other than 0°F.
Outlet setpoint temp for indirect HW (Indir HW Setp)
When a HW call for heat becomes active, the control will control the firing rate of the boiler in order to maintain the outlet water temperature at this setpoint. This parameter can be changed by accessing parameter 4AX. The temperature range of this parameter is 50°F (10°C) to 190°F (88°C). The default value is 180°F (82°C).
Cascade max SH step power based (Max outl temp)
When a system supply sensor is connected, each burner applies this setpoint to its outlet sensor during a space heating call for heat. The controls limit the modulation of each burner in order to maintain the system supply temperature at the setpoint. If an outlet temperature approaches this setting, the controls will also limit the modulation of that burner in order to not exceed the setting. The control uses parameters 4AD and 4AE to turn the burner off and back on based on this setting as well. This parameter can be changed by accessing parameter 4AY. The temperature range of this parameter is 32°F (0°C) to 212°F (100°C). The default value is 185°F (85°C).
Cascade DHW setpoint offset for all members
Not used.
On the tabs at the top of the window (FIG.
Figure 6-7 Parameter Set 4C
Config SH control
The Config SH Control parameter selects the method used to control the modulation of the boiler. This parameter must always be set to 2.
BMS
If BMS control of Cascade has been selected in parameter 4CG, the control must know how to use the
default value is 0.
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