Lochinvar 400 - 801 Control modes, SH Ramp Delay, Controlling Sensor, BMS Active / Inactive

Service Manual

1Service

SH Ramp Delay
	Please note that the brackets ([])
NOTICE
	denote screen status.

The SMART SYSTEM control can be programmed to limit the firing rate for a fixed period of time at the start of a space heating demand. There are six (6) possible limits, each with their own time delay. The first limit applies as soon as the burner starts. Once its time delay expires, the second limit is applied and its timer begins. The control steps through these limits until the 6th (sixth) limit expires. Note, however, that the rate can be held to less than 100% if so desired. The installer can adjust the firing limits and time delays by accessing parameter G4. Once this parameter is selected, the screen will show the step number, the time delay for that step and the limit value corresponding with that step. If the installer wishes to adjust one of the values in that step, he can press the NAVIGATION dial until the value he wishes to change is flashing. The installer can then rotate the NAVIGATION dial to adjust that value. If the installer presses the RIGHT SELECT [SAVE] key while the limit value is flashing, the step value will flash again. The installer can then select the next step and adjust the delay and limit values corresponding with that step.

When finished, the installer can press the RIGHT SELECT [SAVE] key to store the new settings, or the LEFT SELECT [EXIT] key to return to the G parameter list without saving the changes. The delay value can be set between 0 minutes and 120 minutes. The limit value can be set between 0% and 100%.

H: Control modes

Controlling Sensor

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 boiler and the inlet sensor regulates the firing rate based on the inlet water temperature of the boiler. 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 supply sensor temperature. The default sensor is the Outlet Sensor.

BMS Thermostat Input (Active / Inactive)

When controlling the boiler through the 0 - 10V BMS input or through ModBus, the boiler can be enabled one of two ways. With parameter H2 set to ACTIVE, the boiler will enabled by closing the Room Thermostat 1 input. With parameter H2 set to INACTIVE, the boiler will be enabled by the voltage level on the 0 - 10V input (in the case of 0 - 10V BMS control), or the 0 - 10V input value received through ModBus. The default value is INACTIVE.

BMS (Active / Inactive)

The set point or modulation of the boiler may be controlled through the 0 - 10V BMS input or through Modbus. When parameter H3 is set to INACTIVE, the 0 - 10V input will be ignored. When set to ACTIVE, the set point or modulation will be controlled by the voltage on the 0 - 10V input (in the case of 0 - 10V BMS control), or the 0 - 10V input value received through ModBus. The default value is INACTIVE.

Figure 1-2Ramp Delay Interval

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