Hot Water with Thermal Shock Protection Modulating Lead/Lag

The Chief Dispatcher Model JC-CDHWTSP optimizes hot water system performance and helps extend boiler life.  Blend valves are used to allow off-line boiler warm-up and prevent thermal shock.

2 to 4 Modulating Boilers

• Hot water supply header temperature is maintained using accurate PID control
• “Unison” boiler modulation to ensure even heat delivery
• Lag boilers are brought up to the “Unison” firing rate using a predetermined Ramp Rate to meet the heating load with minimum overshoot
• When desired, the operator may set the “Unison” firing rate manually
• Each boiler has an individual boiler outlet temperature sensor
• If any boiler approaches its high temperature shutdown limit, it will cut back its firing rate individually to prevent a boiler trip

Boiler Pump Sequencing

• It keeps the lead boiler pump running to ensure accurate header temperature sensing
• Provides pump shutdown delay for boiler cool down

Thermal Shock Protection

• Individual boiler outlet 3 way recirculating valves are automatically positioned based on the boiler start sequence, boiler outlet and return water temperatures
• If the boiler return water temperature drops below a low temperature setpoint, the valve opens to allow hot boiler outlet water to blend with cold return water temperature
• During a cold startup, outlet water is recirculated by the 3-way valve until the boiler is warm, and then the valve is very slowly open to the header to bring the boiler on-line without thermal shock

Outdoor Reset

• Saves energy by lowering supply header temperature setpoint as the outside air temp increases
• Operating cost is reduced during warmer days
• Hot water supply setpoint may be set manually

Time of Day / Week Setback

• Saves energy by lowering supply header temperature setpoint during times when heating requirement is reduced, such as at night or on weekends and holidays

Domestic Hot Water Priority

• A temperature switch will override any setpoint input and force the header supply temperature setpoint to a Domestic Hot Water Setpoint
• A relay output is available to start a domestic hot water pump if required

Condensing Boiler Logic

• Maximizes the number of boilers running near low fire to maximize efficiency

4 Boiler Controller Front Panel

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Panel Details
Controller: Case Size: Enclosure Type:	PWC  (Click here for a complete hardware specifications) 19¼" H X 18" W X 8½" D Wall mounted, Weight: 55 lbs.
Inputs
Hot Water Temperature: Outlet Water: Return Water: Outdoor Air: BAS Reset Setpoint: BAS, Boiler Disable: Limits: Boiler Lockout: Domestic HW Priority:	0 to 300° F, Thermistor Thermistor (each boiler) Thermistor (each boiler) Thermistor (non “-BAS” version) 4-20 mAdc (“-BAS” version) 120 Vac, optically isolated 120 Vac, optically isolated (each boiler) 120 Vac, optically isolated (each boiler) 120 Vac, optically isolated
Outputs
Boiler Modulation: Balancing Valve: Boiler Start: Pump Start: Domestic HW Circulation Pump:	Isolated: 4-20 mAdc or 0-135 ohm (each boiler) Isolated: 4-20 mAdc (each boiler) Dry contact, 8FLA, ½ HP, 120 Vac (each boiler) Dry contact, 8FLA, ½ HP, 120 Vac (each boiler) Dry contact, 8FLA, ½ HP, 120 Vac

Optional Features	Catalog Number
Historical Trending	190604
Telephone Modem	190603
Building Automation System (BAS)	add "-BAS" suffix
Condensing Boiler Logic	add "-C" suffix
Order Sensors Separately (Quantity as Required)	Catalog Number
Hot Water Thermistor Temperature Sensor 0 to 300F, 4 1/2" depth	70610
Thermowell, SS, 4 1/2" x 1/2" NPT	70610W
Outside Air Thermistor Temperature Sensor with weatherproof cover	70612