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1 Service
Figure 1-2_Ramp Delay Interval
H: Control modes
H1: SH controlling sensor (boiler only)
The SH controlling sensor parameter selects the sensor the control will use to regulate the boiler firing rate. This parameter is adjustable by the installer by accessing parameter H1. The sensor selections are as follows: The outlet sensor regulates the firing rate based on the outlet water temperature of the unit and the inlet sensor regulates the firing rate based on the inlet water temperature of the unit. If the outlet sensor is selected, and the optional system supply sensor is connected, the control will regulate the firing rate based on the system sensor temperature. If the inlet sensor is selected, and the optional system return sensor is connected, the control will regulate the firing rate based on the system return sensor. The default sensor is the Outlet Sensor.
H2: Enable input (active / inactive)
The boiler or water heater can receive a call for heat in two different ways. First, an external contact (like a tank thermostat) or sensor (like a tank sensor) can generate a call for heat. Second, the
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H3: BMS input (active / inactive)
When the building management input is enabled, the control modulates the unit or the cascade based on the voltage on the
H4: Cascade (active / inactive)
Boilers or water heaters may be part of a group of units sequenced together. When so connected, each heater must be programmed to operate as part of the Cascade. This is done by setting the Cascade to Active. This setting is adjustable by the installer by accessing parameter H4. The default value is Inactive.
H5: Sequencer (active / inactive) (boiler only)
The individual stages in the heater can be controlled separately with an external sequencer. This setting is adjustable by the installer by accessing parameter H5.
H6: ModBus (active / inactive)
When the optional ModBus board is installed, the heater can be monitored and controlled by a Building Control System (BCS). If the heater is to be controlled through ModBus, parameter H6 must be set to ACTIVE. The default value is Inactive.
H7: ModBus timeout
When the heater is being controlled or is receiving temperature readings through ModBus, the information sent to the heater must be refreshed periodically. If the heater does not receive new information after a timeout, it will revert to local temperature readings and control. This prevents the heater from running for too long should the ModBus connection be lost. To adjust the length of this timeout, access parameter H7. The range of this parameter is 0 to 120 seconds. The default value is 10 seconds.