Building Heating Hot Water System

This shows a steam to hot water convertor controls. The central monitoring panel displays sensors, actuators, charts, graphs, gauges, and status pilot lights. Also the system's PID controller can be tuned at the central monitoring panel.
Sequence Of Operation: This controls the hot water temperature leaving the steam convertor (H.W.S.) by modulating the steam valve. The setpoint of the hot water temperature is automaticlly reset from outdoor air drybulb temperature (O.A.T.)

Reset Schedule: The set point reset schedule, and its current set point, is shown on an interactive reset schedule graph. The reset line/curve can be modified at the central monitoring panel.

Current Value Chart: The measured HWS temperature strip chart is shown that continually plots the hot water temperature during the previous 60 minutes.

Analog Gauges: Gauges are provided on the central monitoring panel that display: Outside air dry bulb temperature(OAT), hot water temperature leaving the convertor(HWS), and the controller output (CO) value to the steam valve.

System Chart: Select the button to view the hot water system strip chart that continuosly records the OAT, HWS, and CO gauge values, plus the desired hot water supply temperature setpoint during the previous 100 minutes.

Controller Status: A 5-state status pilot light is included for the local controller, shown inside this controller's diagram.

PID Controller: The central monitoring panel can tune the PID loop. It displays and has access to adjust the following values associated with the controller:
1.) HWS Temperature Setpoint(SP) - When this radio button is checked it overrides the OAT reset and selects a manual mode.
2.) Proportional(P) Value - When this radio button is checked the value is available for change.
3.) Intergral(I) Value (repeats/minute) - When the checkbox is un-checked the integral is is ignored. When the radio button is checked the value is available for change.
4.) Derivative(D) Value - When the checkbox is un-checked the derivative value is ignored. When the radio button is checked the value is available for change.
5.) Steam Valve Position(CO): 0 to 100% - When this radio button is checked it overrides the controller output (CO) and selects a manual mode.

Choose the radio button for desired value to adjust. Select the increment, then use the or button to change value.

Actuator Status: A 5-state status pilot light monitors the actuator status: fully open (ON), fully Closed (NORMAL OFF), or modulating (INTERMITTENT), and disabled/repairing (DEFECTIVE). If the actuator's local positioning circuit detects a fault, the status will show ALARM.
Convertor Steam H.W.R H.W.S O.A.T Valve
Tune Controller:
SP: P: I: D: CO:
     
HWS Setpoint Reset vs OAT Hot Water Supply Temperature SP (°F) OAT (°F) HWS (°F) Minutes

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