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Discontinued - Replaced By: 423

Part of the 420 Series

Ordering Code: 420

UPC: 779655042009

Boiler Reset Module, One tN4, Boiler, DHW and Setpoint


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Control Selector

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  • System setback (with optional Timer)
  • warm weather shut down, Zone Synchronization
  • DHW priority (optional), setpoint operation
  • One touch overrides (with optional User Switch)
  • Outdoor temperature reset, indoor temperature feedback
  • Single on/off, or modulating boiler control, DHW control
  • Boiler protection, powered pump outputs
  • DHW Post Purge, System control for up to 24 zones
  • automatic boiler differential, exercising
Agency Approvals CSA C US, meets Class B: ICES & FCC Part 15
Ambient Conditions Indoor use only, 32 to 122 degrees F (0 to 50 degrees C), RH less than or equal to 80 percent to 88 degrees F (31 degrees C), down to 50 percent above 104 degrees F (40 degrees C), Altitude less than 6560 ft. (2000 m), Installation Category II, Pollution Degree
Boiler Relay 115 V (ac) 5 A, 1/6 hp
Combined Load 10 A max (for DHW and Primary Pump)
Control Type Microprocessor control, this is not a safety (limit) control
Demand 20 to 260 V (ac) / 0.1 VA at 24 V
DHW - Zone Valve 24 V (ac) 8 VA max
Dimensions 3-5/8" H x 5-3/8" W x 9/16" D (92 x 137 x 14 mm)
Enclosure Material No Enclosure
Enclosure NEMA Rating Does Not Apply To Product
Hydronic - HVAC Control Type Boiler Reset Module
Modulating Output 0-10 V (dc) minimum 2500 ohms
Power Supply Provided by interconnected tekmarNet Zone Manager
Pump Relay 115 V (ac) 5 A, 1/6 hp
Sensor NTC thermistor, 10 k ohms at 77 degrees F (25 degrees C plus / minus 0.2 degrees C) Beta=3892