blockEnableLead_headered
Sequence to enable or disable the lead pump of plants with headered primary chilled water pumps
Information
Block that enables and disables the leading primary chilled water pump, for plants with headered primary chilled water pumps and parallel chillers, according to ASHRAE Guideline 36-2021, section 5.20.6 Primary chilled water pumps, part 1, 2, and 3.
- Primary chilled water pumps shall be lead-lag. Note that the lead-lag control is implemented in a separate sequence.
-
Enable lead primary chilled water pump when any chiller CHW isolation valve
uChiIsoValis commanded open. Disable the lead primary chilled water pump when all chiller CHW isolation valves are commanded closed. - Or if the plant has the waterside economizer, enable lead primary CHW pump when any chiller CHW isolation valve is commanded open or waterside economizer is enabled. Disable the lead primary CHW pump when all chiller CHW isolation valves are commanded closed and WSE is disabled.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nChi | 2 | Total number of chiller CHW isolation valves |
| Boolean | have_WSE | True: the plant has waterside economizer |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput[nChi] | u1ChiWatIsoVal | Chilled water isolation valve commanded position | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanInput | uWse | Waterside economizer proven on status: true=ON | |
| Buildings.Controls.OBC.CDL.Interfaces.BooleanOutput | yLea | Lead pump status setpoint |
Revisions
-
August 1, 2019, by Jianjun Hu:
First implementation.